Contents
2015
Volume: 35 Issue 8
53 Article(s)
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Atmospheric Optics and Oceanic Optics
Cloud Contaminated Satellite Data Processing Method in CO2 Retrieving
Jiang Xinhua, Wang Xianhua, Ye Hanhan, Bu Tingting, Sang Hao, and Yi Weining
Cloud contamination of greenhouse gas satellite data is investigated by using O2-A band, the scattering effects on CO2 retrieval from optical path-length is analyzed and a new method for solving cloud contamination problem is proposed. The results show that 83.58%, 9.70%, and 6.72% L2 data are contained in clear, cloudCloud contamination of greenhouse gas satellite data is investigated by using O2-A band, the scattering effects on CO2 retrieval from optical path-length is analyzed and a new method for solving cloud contamination problem is proposed. The results show that 83.58%, 9.70%, and 6.72% L2 data are contained in clear, cloud, and undetermined scenes. The CO2 retrieval of these clear scene and cirrus scene appears highly agreement with L2 product, but the other CO2 retrieval is generally lower than L2 product. Cloud screening in O2-A band has its own advantage but also existing insufficiency like the misidentifying of thin cirrus. Fortunately, the scattering correction method through optical path-length is an effective supplement to O2-A band cloud screening as it can improve CO2 retrieval bias due to cirrus scattering, combining them to account for cloud contamination is a promising method. Simultaneously, undetermined-I scene should be pay more attention since these undetermined scene contained abundance scene covered by cirrus..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 801001 (2015)
Phase Error Compensation in Airborne Synthetic Aperture Lidar Data Processing
Lu Tianan, and Li Hongping
In order to study the influence of atmospheric turbulence on the image of synthetic aperture lidar (SAL),based on Monte-Carlo random factor,numerical simulation of phase screens following the Kolmogorov spectrum is introduced.The SAL images with different turbulence and different wavelengths are calculated.AdditionallyIn order to study the influence of atmospheric turbulence on the image of synthetic aperture lidar (SAL),based on Monte-Carlo random factor,numerical simulation of phase screens following the Kolmogorov spectrum is introduced.The SAL images with different turbulence and different wavelengths are calculated.Additionally,with different wavelengths and slant ranges,the relations of turbulence intensity and the ratio of synthetic aperture length to atmospheric coherent length are analyzed.The results show that the atmospheric turbulence can severely affect the azimuth resolution of the SAL image.With the increase of turbulence intensity,SAL imaging defocus is becoming more and more serious,and eventually the target can not be distinguished.With the same turbulence intensity,when the beam wavelength is longer,the SAL image quality is better.For the distortion of SAL image caused by turbulence effect,improved rank one phase error estimation (IROPE) method is used to compensate the phase errors.When the atmospheric coherent length is greater than the real aperture length,IROPE method can effectively improve the focusing effect of images and increase the imaging resolution..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 801002 (2015)
Effects of Beacons and Wave-Front Detecting Modes on Control Performance of Adaptive Optics Systems
Luo Qi, and Li Xinyang
Adaptive optics systems need beacons to detect wave- front information.Different modes of bea-cons and wave- front detecting have a great influence on the performance criterion such as the system band-width and stability.Researching the performance of the system is full of critical meaning to properly design and evaluaAdaptive optics systems need beacons to detect wave- front information.Different modes of bea-cons and wave- front detecting have a great influence on the performance criterion such as the system band-width and stability.Researching the performance of the system is full of critical meaning to properly design and evaluate a system.Based on the system work flow,the light wave characteristics of beacons,the methods of exposure,read-out of wave-front sensors,and the transfer function models of adaptive systems are built using mechanism analysis methods.The calculation equations of system bandwidth and phase margin are de-rived.The effects of sample frequency and controller parameter on system performance are studied.Results show that different modes of beacons and wave-front detecting can cause different system time delays,which alter the system bandwidth and stability..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 801003 (2015)
Adaptive Optics Control Technique Based on Orthogonal Mode Perturbance Gradient Descent Algorithm
Chen Bo, Yang Jing, Li Xinyang, Yang Xu, and Li Xiaoyang
For wavefront sensorless adaptive optics systems,a control technique based on the orthogonal mode perturbance gradient descent (OP_GD) algorithm is proposed.The feasibility and convergence speed of this method are analyzed comparing with the serial gradient descent algorithm and stochastic parallel gradient descent (SPFor wavefront sensorless adaptive optics systems,a control technique based on the orthogonal mode perturbance gradient descent (OP_GD) algorithm is proposed.The feasibility and convergence speed of this method are analyzed comparing with the serial gradient descent algorithm and stochastic parallel gradient descent (SPGD)algorithm.After that,an adaptive optics setup with liquid crystal spatial light modulator (LC_SLM) is set up,and the convergence characteristic is analyzed experimentally.The results show that this algorithm has a good global convergence characteristic and almost the same convergence speed as SPGD algorithm.However,compared with SPGD algorithm,the orthogonal mode perturbance gradient descent algorithm is easier to perform with hardware because the pseudo-random sequence generator is unnecessary..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 801004 (2015)
Propagation of Beam Array with Random Phase through Atmospheric Turbulence in a Slant Path
Lu Fang, Zhao Dan, and Han Xiang′e
Based on the extended Huygens-Fresnel principle, the properties of a beam array with random phase distributions propagation through a turbulence atmosphere in a slant path are analytically investigated. Influences of turbulence intensity, duty ratio, transmission height and the phase difference between the beams on theBased on the extended Huygens-Fresnel principle, the properties of a beam array with random phase distributions propagation through a turbulence atmosphere in a slant path are analytically investigated. Influences of turbulence intensity, duty ratio, transmission height and the phase difference between the beams on the average intensity of the beam array are researched. The results show that turbulence can cause the decrease of the peak and the spreading of beam; at the same time, the smaller the duty ratio, the smaller peak intensity , the combination effect is even worse; with the random phase difference between the beams increasing, the main peak intensity decreases fast and the far-field coherent combining irradiance distribution gradually evolves into the pattern of the single Gauss beam distribution model. The results for a slant path are compared with those for a horizontal path, and as a result, the influence of the atmospheric turbulence to the beam spreading along the slant path is much smaller than that along the horizontal path. The mathematical model and calculation result can offer a reference for choosing and evaluating different combining schemes..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 801005 (2015)
Diffraction and Gratings
Design of Optical Elements for Beam Shaping and Uniform Illumination in Laser Digital Projection Display System
Zhang Wei, Liang Chuanyang, Li Jin, and Rui Dawei
Laser light source is widely used in digital projection display system in recent years,and the laser display is representing one of the future development trend of display technology.In laser digital projection display system,diffractive optical element (DOE) can realize uniform illumination on light modulator utilizinLaser light source is widely used in digital projection display system in recent years,and the laser display is representing one of the future development trend of display technology.In laser digital projection display system,diffractive optical element (DOE) can realize uniform illumination on light modulator utilizing its good beam shaping ability and small size.The advantages of adopting DOE are not only higher efficiency of light source,better uniformity of illumination but also making the display system more compact.DOE that has 16 phase level is designed by using the Fourier transform step-iterative algorithm and the function of beam shaping and uniform illumination is realized.The simulation results show that the energy efficiency of light source is better than 85% ,the uniformity of illumination is higher than 90%,and the Root-Mean-Square of difference of intensity profile compared with the ideal one is less than 7%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 805001 (2015)
Fiber Optics and Optical Communications
High Sensitivity Tapered Fiber SERS Probe and Its Application on Pesticide Residues Detection
Lei Xing, Liu Ye, Huang Zhulin, Yao Bo, and Mao Qinghe
The influences of induced laser power and reaction time on the properties of tapered fiber surface enhanced Raman scattering (SERS) probes by the laser induced chemical deposition method (LICDM) are studied in experiments. Under an optimized experimental conditions as 90 mW induced laser power and 50 min reaction time,The influences of induced laser power and reaction time on the properties of tapered fiber surface enhanced Raman scattering (SERS) probes by the laser induced chemical deposition method (LICDM) are studied in experiments. Under an optimized experimental conditions as 90 mW induced laser power and 50 min reaction time, the prepared taper fiber SERS probes possess the highest sensitivity, when detecting a low concentration as 1.0 × 10- 7 mol/L of methyl parathion (MP) solution with a portable Raman spectrometer. Moreover, the prepared probes with LICDM show good repeatability for SERS detections, which may have potentials on rapid and field detection of pesticide residues..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 806001 (2015)
A Joint Detection and Iterative Decoding Algorithm of Optical Concatenated Space-Time Code
Wang Huiqin, Wang fen, Cao Minghua, and Ke Xizheng
After introducing optical multiple input and multiple output (MIMO) channel model,by feed backing high reliability of low density parity check (LDPC) decoding results to BLAST decoder,a joint detection and iterative decoding algorithm suitable for LDPC-BLAST optical concatenated space-time coding system is proposed in After introducing optical multiple input and multiple output (MIMO) channel model,by feed backing high reliability of low density parity check (LDPC) decoding results to BLAST decoder,a joint detection and iterative decoding algorithm suitable for LDPC-BLAST optical concatenated space-time coding system is proposed in this paper.Using Monte Carlo Method,the bit error rate (BER) of the proposed decoding algorithm is analyzed and compared with that of the originally simple concatenated decoding algorithm.It is showed that the BER of the proposed joint detection and iterative decoding algorithm is better than that of the existing simple decoding algorithm.Besides,the influence of iterative times on the proposed decoding algorithm performance is analyzed with numerical analysis method.The results show that the number of iteration should not be too large when the system BER and decoding algorithm complexity is eclectically considered..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 806002 (2015)
Research on the Ultra-Weak Reflective Fiber Bragg Grating Sensing Technology Based on Optical Frequency Domain Reflection Technology
Li Zhengying, Sun Wenfeng, and Wang Honghai
The rapid development of fiber grating sensing technology in recent years puts forward higher request on the multiplexing capacity and spatial resolution. The demodulation of quasi-distributed fiber Bragg grating (FBG)sensing with high capacity and high spatial resolution is achieved by adopting ultra-weak FBGs and optThe rapid development of fiber grating sensing technology in recent years puts forward higher request on the multiplexing capacity and spatial resolution. The demodulation of quasi-distributed fiber Bragg grating (FBG)sensing with high capacity and high spatial resolution is achieved by adopting ultra-weak FBGs and optical frequency domain reflection technology (OFDR). In order to achieve the grating demodulation, the optimization of beat frequency signal separation and nonlinear correction to realize the extraction of fiber grating position information with high spatial resolution as well as the separation of the grating beat signal in the time domain are used respectively. Then the grating reflection spectral information by using the Hill Hilbert transform is restored. The system multiplex 200 FBGs along a single optical fiber have the same center wavelength of 1552.8 nm, reflectivity of 0.1% , space interval of 20 mm. The experimental results shows that, in the temperature range of -10 ℃～80 ℃, the measured center wavelength of FBG has good linearity of 99.6%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 806003 (2015)
Fabrication and Properties of Flexible Chalcognide Fiber Image Bundles
Zhai Chengcheng, Zhang Bin, Qi Sisheng, Guo Wei, Yang Zhiyong, Yang Anping, Zhang Mingjie, Yang Yan, Yu Yi, Wang Rongping, Tao Guangming, Tang Dingyuan, and Barry Luther-Davies
A high performance thermoplastic polymer, polyetherimide (PEI), which is thermally compatible with some chalcogenide glasses, is introduced as a cladding material to fabricate fiber image bundles. As2S3/PEI image bundles consisting of 900 fibers are fabricated through a stack and draw approach. The loss of the fibers, A high performance thermoplastic polymer, polyetherimide (PEI), which is thermally compatible with some chalcogenide glasses, is introduced as a cladding material to fabricate fiber image bundles. As2S3/PEI image bundles consisting of 900 fibers are fabricated through a stack and draw approach. The loss of the fibers, the dark fiber ratio, the resolution and crosstalk of the image bundles are characterized. The As2S3/PEI shows a good transmitting property in the 2 μm to 6 μm spectral region. The background loss is about 0.5 dB/m, and the peak loss at 4.0 μm due to S-H impurity absorption is about 3.5 dB/m. The fiber bundle containing 900 fibers with a diameter of 80 μm has a dark fiber ratio of 1%, exhibits a resolution of 7 line/mm and shows crosstalk of 1%. Clear infrared image of a soldering iron tip is obtained through this fiber bundle. The flexibility of the fiber bundles is achieved by dissolving the PEI into a solvent dimethylacetamide (DMAC). Flexible high-resolution chalcogenide fiber image bundles may be fabricated through the stack and draw approach using a thermoplastic polymer which can be dissolved into special solvents as an interlayer material similar to the‘acid-dissolved glass’..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 806005 (2015)
Dynamic Real-Time Calibration Method for Fiber Bragg Grating Wavelength Demodulation System Based on Tunable Fabry-Perot Filter
Wang Peng, Zhao Hong, Liu Jie, Chen Junqi, and Han Xu
In order to reduce measuremental errors of fiber Bragg grating (FBG) wavelengths resulted from the driving element of tunable Fabry- Perot (F- P) filter, which has the characteristics of temperature drift and nonlinearity, an improved dynamic real-time calibration approach is proposed after analyzing and comparing two In order to reduce measuremental errors of fiber Bragg grating (FBG) wavelengths resulted from the driving element of tunable Fabry- Perot (F- P) filter, which has the characteristics of temperature drift and nonlinearity, an improved dynamic real-time calibration approach is proposed after analyzing and comparing two kinds of real-time correction systems respectively with series and parallel structures. Then the real-time correction system with improved concatenation structure is investigated. The reference grating module with good thermal stability is designed to guarantee that wavelengths of four reference FBGs in the module keep constant for a long time. An accurate resistance temperature detector (RTD) is integrated into the model and clung to the reference FBGs. Before measurement, the correlation between the wavelengths of four reference FBGs and temperatures measured by RTD is calibrated. By reference points provided by referenced FBGs, the function between transmission wavelength and driving voltage of tunable F-P filter is adjusted in real time during every scanning period. The experimental results demonstrate that the maximum error is ±3 pm using the improved dynamic realtime calibration method to demodulate wavelengths of FBGs. Compared with the method to determine center wavelengths by direct acquiring driving voltages, the accuracy is enhanced 6 times. Compared with the reported method using series structure, the accuracy raises 3 times..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 806006 (2015)
Fourier Optics and Signal Processing
Nonlinear Optical Image Encryption
Hou Junfeng, Huang Sujuan, and Situ Guohai
Taking the advantages of the traditional double random phase encoding and nonlinear optics techniques, a novel nonlinear optical image encryption technique based on self-phase modulation of photorefractive crystal is proposed, the robustness and security are analyzed. The plaintext image is encrypted into a stationary Taking the advantages of the traditional double random phase encoding and nonlinear optics techniques, a novel nonlinear optical image encryption technique based on self-phase modulation of photorefractive crystal is proposed, the robustness and security are analyzed. The plaintext image is encrypted into a stationary complex random white noise via two statistically independent random phase masks and two sequential nonlinear propagations. The decryption is the inverse process of the encryption, which can be implemented either optically or digitally using nonlinear digital holography. Numerical simulation results demonstrate that the proposed nonlinear optical image encryption technique is robust against additive and multiplicative noise, resists effectively against the chosen plaintext attack or known plaintext attack based on phase retrieval in comparison with the traditional linear encryption techniques..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 807001 (2015)
Geometric Optics
100-GHz and 200-GHz All-Optical Clock Recovery Based on F-P Cavity and SOA
Wu Yue, Huo Li, and Lou Caiyun
The principle, how the Fabry-Pérot (F-P) cavity followed by amplitude equalizing system based on semiconductor optical amplifier (SOA) and cascade offset filter achieves all-optical clock recovery from the signal whose bit rate is a multiple of the free spectral range (FSR) of the F-P cavity, is explained. How theThe principle, how the Fabry-Pérot (F-P) cavity followed by amplitude equalizing system based on semiconductor optical amplifier (SOA) and cascade offset filter achieves all-optical clock recovery from the signal whose bit rate is a multiple of the free spectral range (FSR) of the F-P cavity, is explained. How the parameter of the filter in the amplitude equalizing system affects the amplitude fluctuation of the recovered clock is researched and the best parameter in theory is obtained. In the experiment, to solve the problem that is great fluctuation after F-P cavity because of the phase difference between the optical signals in different channels of the optical time division multiplexed (OTDM) system, a wavelength conversion system is utilized. Finally, by using the F-P cavity with 102 GHz FSR and amplitude equalizing system, 102 GHz optical clock recovery from 102 Gb/s return to zero code on-off Keying (RZ-OOK）signal and 204 GHz optical clock recovery from 204 Gb/s RZ-OOK signal are experimentally demonstrated. The 102 GHz recovered clock has an amplitude fluctuation of 8.5% and a timing jitter less than 236 fs, and the 204 GHz recovered clock has an amplitude fluctuation of 9.4% and a timing jitter less than 251 fs..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 806004 (2015)
Imaging Systems
Reconstruction of Scannerless 3D LIDAR Range Image Based on the Adaptive Block Grayscale-Range Markov Random Filed Model with Optimizing Weights
Hao Gangtao, Du Xiaoping, Song Jianjun, and Song Yishuo
Aim to improve the low resolution and noisy range image from scannerless three-dimensional (3D)LIDAR,a reconstruction approach of sparse range image based on adaptive block grayscale-range Markov random filed (MRF) with optimizing weights is proposed through integrating a monocular camera with high resolution.A grayscaAim to improve the low resolution and noisy range image from scannerless three-dimensional (3D)LIDAR,a reconstruction approach of sparse range image based on adaptive block grayscale-range Markov random filed (MRF) with optimizing weights is proposed through integrating a monocular camera with high resolution.A grayscale-range MRF multilevel correlogram is established.On this basis a fast interpolation is obtained without the texture copying by using block processing and the resconstruciton speed is improved.The edge penalty factor based on simple linear iterative clustering (SLIC) superpixels segmentation is applied to preserve the image structure details.In order to get a robust performance,both the spatial depth kernel function and grayscale similarity kernel function with adaptive adjustment of standard deviation of kernel funciton for different neighborhood systems are used as guided map.The conjugate gradient algorithm is performed for each neighborhood system to fast optimize the global energy function.The experiments with standard image datasets and real images show that proposed method have better performance than bilinear interpolation,bilateral filter and standard MRF,so that it is effective for realizing the image reconstruction of scannerless 3D LIDAR..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 811001 (2015)
Hyperspectral Imaging Based on Symmetric Wedgy Interferometric Cavity
Bai Caixun, Li Jianxin, Meng Xin, Shen Yan, and Zhu Rihong
Interferometric hyperspectral imaging is a popular technology with wide application in many fields.Miniaturization of instrument is conducive to promotion of the imaging technology.In order to explore a new technical scheme,a new method of interferometric hyperspectral imaging based on symmetric wedgy cavity is researcInterferometric hyperspectral imaging is a popular technology with wide application in many fields.Miniaturization of instrument is conducive to promotion of the imaging technology.In order to explore a new technical scheme,a new method of interferometric hyperspectral imaging based on symmetric wedgy cavity is researched.A symmetric wedgy cavity is inserted into the imaging system to obtain the modulating relationship between optical path difference and field angle.By analyzing the working principle of the system,a model of the imaging system is designed while the major parameters such as wedge angle of interferometric cavity,reflectance,object lens,and the push- broom mode are discussed.Moreover,the proposed method is verified by the simulation with Zemax.A prototype is developed and good experimental results of lasers and actual scene objects are obtained.The research shows that besides high throughput and high spectral resolution,the advantage of miniaturization is also simultaneously achieved in this method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 811002 (2015)
Hyperspectral Compressed Sensing Based on Prior Images Constrained
Tan Shiyu, Liu Zhentao, Li Enrong, and Han Shensheng
When the sampling ratio and signal- to- noise ratio (SNR) is low, the noise of multispectral image increases, quality of the reconstructed images inevitably degrades. In order to improve the quality of multispectral image, a new prior image constrains hyperspectral compressed sensing (PICHCS) method is proposed. The spWhen the sampling ratio and signal- to- noise ratio (SNR) is low, the noise of multispectral image increases, quality of the reconstructed images inevitably degrades. In order to improve the quality of multispectral image, a new prior image constrains hyperspectral compressed sensing (PICHCS) method is proposed. The spatial and spectral correlations in hyperspectral imaging is exploited in PICHCS to reconstruct the primitive images. Prior images obtained by averaging the adjacent spectral primitive images are used as constraints for the compressed sensing image reconstruction. By subtracting each target image with the corresponding prior image, the obtained difference images are expected to sparse and reconstructing the difference images, some of the high SNR characteristics of the prior image are retained in the reconstructions. The feasibility of the method is verified by numerical simulations and experiments. Comparative studies are made for reconstructions obtained with the total variation and low rank joint algorithm and those with PICHCS under different sampling ratios and SNRs. The results indicate that PICHCS improve reconstruction quality of hyperspectral images from a low sampling ratio or SNR dataset, which can reduce the requirement of sampling ratios and the system SNR..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 811003 (2015)
Instrumentation, Measurement and Metrology
Optical Design and Stray Light Suppression of A New Portable Echelle Spectrometer
Yang Jin, Yin Lu, Yao Xuefeng, Bayanheshig, Tang Yuguo, and Zhu Jiwei
Echelle spectrometer is becoming a hot research and focus of modern spectrograph with the outstanding features of high resolution, small size, full spectrum transient direct- reading. In order to further refine its volume, improve the signal to noise ratio and the detection limit, a new structure of echelle spectrometeEchelle spectrometer is becoming a hot research and focus of modern spectrograph with the outstanding features of high resolution, small size, full spectrum transient direct- reading. In order to further refine its volume, improve the signal to noise ratio and the detection limit, a new structure of echelle spectrometer is designed. By folding main optical path, the new design has smaller size and lower stray light without reducing spectral resolution and image quality. It′ s optical size is less than 165 mm × 70 mm × 65 mm, and spectral resolution is 0.06 nm@200 nm. The baffle and diaphragm is designed to further reduce stray light. Through ray tracing simulation, the stray light of the new echelle spectrometer is less than 2×10-5 , the signal to noise ratio is improved significantly..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 812001 (2015)
Study on the Aberration Correction Method of Solar Grating Spectrometer Based on Adaptive Optics
Zheng Lianhui, Gu Naiting, Rao Changhui, and Qiu Qi
Grating spectrometer is one of important tool to study the thermodynamics properties of the solar atmosphere with different height distributions, but its imaging performance will be limited by the wavefront aberration generated by atmospheric turbulence and optical system adjusting errors and so on, so daptive optics (Grating spectrometer is one of important tool to study the thermodynamics properties of the solar atmosphere with different height distributions, but its imaging performance will be limited by the wavefront aberration generated by atmospheric turbulence and optical system adjusting errors and so on, so daptive optics (AO) is needed to compensate the influence of the wavefront aberration. However, the traditional adaptive optics can not be directly applied in the grating spectrometer, since the tiny slit will filter the wavefront aberration to a certain extent. The influence of filter slit on the adaptive optics correction is studied. A differential correction method based on the sensitivity of the filter slit is proposed and the numerical simulation is conducted. The results show that after the adaptive optics correction, the spectral resolution is notably improved, and also the energy utilization η is considerably improved, better than 90% with a slit width of 3 times diameter of Airy spot..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 812002 (2015)
Opto-Mechanical Structure Design and Thermal Optical Analysis on Zoom Lenses of Optical-Electronic Platform
Liu Ming, Zhang Guoyu, Geng Shubin, Xiao Zuojiang, and Han Xu
In the light of zoom lenses of optical-electronic counteraction platform, an opto-mechanical structure is designed and thermal optical property is analyzed. Based on 30～120 mm zooming design requirement, the cam mechanism is adopted to design. In order to ensure that the optical system can obtain high resolution imagesIn the light of zoom lenses of optical-electronic counteraction platform, an opto-mechanical structure is designed and thermal optical property is analyzed. Based on 30～120 mm zooming design requirement, the cam mechanism is adopted to design. In order to ensure that the optical system can obtain high resolution images under high-low temperature, thermal deformation of the whole machine under highlow temperature and rigid body displacement under axial temperature field are analyzed by means of finite element method. Subsequently, mirror surface after thermal deformation is fitted by Zernike annular polynomials and introduces into Zemax to obtain variation curve of modulation transfer funciton (MTF), peakto-valley (PV), root mean square (RMS) evaluation function with temperature change to proof of optomechanical design rationality. Finally, the analysis results and temperature adaptability of zoom lenses are verified through high-low temperature reliability experiments..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 812003 (2015)
Computer-Aided Alignment Technology of Multi-Spectral Camera
Zhang Chao, Wei Xuemin, Zhao Xiting, Jiao Wenchun, and Liao Zhibo
Refract optical system using in remote sensing usually has many elements,complicated structure and diffraction limited image quality,which makes the alignment puzzled.Combined with the adjustment mathematical model,the CODE V optical design software and the field interference Zernike coefficient are integrated into theRefract optical system using in remote sensing usually has many elements,complicated structure and diffraction limited image quality,which makes the alignment puzzled.Combined with the adjustment mathematical model,the CODE V optical design software and the field interference Zernike coefficient are integrated into the alignment variables for calculating the misalignment.According to the off-axis three mirror ideal optical system model,the alignment sensitivity matrix is acquired and the correct order of multi misalignment variables is determined,which can overcome the alignment correlation effectively.It is effective and convenient to raise the optical system wavefront error root mean square (RMS) from 0.563 λ (=632.8 nm) to 0.064 λ .After the orbit test,the multi-spectral camera imaging quality is excellent..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 812005 (2015)
Three-Dimensional Reconstruction of Dental Impression Based on Multi-Camera Three-Dimensional Digital Image Correlation Method
Dong Shuai, Dai Yuntong, Dong Eliang, Kang Xin, and He Xiaoyuan
Based on three- dimensional digital image correlation (3D- DIC) method, the three- dimensional shape of dental impression is measured by mosaic techology. Due to the surface feature of the dental impression is complex, a four camera system is utilized for the measurement. The system is made up of two groups of 3D- DIC Based on three- dimensional digital image correlation (3D- DIC) method, the three- dimensional shape of dental impression is measured by mosaic techology. Due to the surface feature of the dental impression is complex, a four camera system is utilized for the measurement. The system is made up of two groups of 3D- DIC subsystems. The local profile is measured by each subsystem and the global morphology is acquired by mosaicking each local profile. Compared with the result of traditional two cameras 3D- DIC method, the proposed method gains a better 3D profile of the complex dental impression, which provides a new way to measure the 3D profile of dental impression, and it also provides reference to the 3D profile measurement of complex surface..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 812006 (2015)
Integrated Optics
Silicon Photonic Crystal Nanobeam Cavities Fabricated by Deep-Etching Method
Yu Ping, Qiu Huiye, Wu Feiqing, Wang Zhuoyuan, Yu Mingyan, and Yu Enjun
A silicon photonic crystal nanobeam caivity based on deep- etching method is presented. Using finite difference time domain (FDTD) method, the influence of deep- etching on the Q factor of nanobeam cavities is designed and analyzed. The calculated results show that the deep- etching scheme can keep the high-Q value cloA silicon photonic crystal nanobeam caivity based on deep- etching method is presented. Using finite difference time domain (FDTD) method, the influence of deep- etching on the Q factor of nanobeam cavities is designed and analyzed. The calculated results show that the deep- etching scheme can keep the high-Q value close to the air-bridge peer, as well as robust mechanical strength. The devices are fabricated on silicon on insulator (SOI) platform using electron beam lithography (EBL) and inductively coupled plasma (ICP). Scanning electron microscope (SEM) and atomic force microscope (AFM) are employed to characterize the morphology of the fabricated nanobeam cavities. The measured transmission spectra indicate that the Q factor of deeply- etched nanobeam cavities surpass 5 × 103 with acceptable insertion loss of less than - 2 dB. These deeply-etched nanobeam cavities can find their applications in on-chip optical sensors or optical filters..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 813001 (2015)
Lasers and Laser Optics
Mechanism Study on the Effect of Planar Ring Resonator Parameters on Ellipticity of Modes in Resonator
Yu Wendong, Wang Jingxian, Chen Linfeng, and Zhang Minghui
Ellipticity of modes in resonator and magnetic fields are two necessary conditions for magnetic sensitivity of ring laser gyroscope. Reducing ellipticity of modes is one of approaches to reduce magnetic sensitivity of ring laser gyroscope. Based on theory of resonator by Jones matrix,the positional principle of establiEllipticity of modes in resonator and magnetic fields are two necessary conditions for magnetic sensitivity of ring laser gyroscope. Reducing ellipticity of modes is one of approaches to reduce magnetic sensitivity of ring laser gyroscope. Based on theory of resonator by Jones matrix,the positional principle of establishing selfconsistent equation is given, the method of choosing modes which exists is given, a theory of calculation on ellipticity of modes is formed. The mechanism of the effect of reflectors′ parameters and angle of folding plane of ring laser on ellipticity of modes in resonator are analyzed by analytical method of numerical value. Two new approaches to reduce ellipticity of modes are advanced, they are achieved by collocating the reflection-inducedretardances of mirrors. The results of research have important significance for study of engineering on reducing magnetic sensitivity of ring laser gyroscope..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 814001 (2015)
Machine Vision
Small Scale Crowd Behavior Recognition Based on Causality Network Analysis
Zhang Xuguang, Liu Chunxia, and Zuo Jiaqian
Crowd behavior recognition is an important research topic in computer vision field. Amid at the properties that the behavior of small scale crowd have the features both microcosmic and macroscopic, a small scale crowd recognition method based on causality network analysis is proposed. The trajectories of each pedestriaCrowd behavior recognition is an important research topic in computer vision field. Amid at the properties that the behavior of small scale crowd have the features both microcosmic and macroscopic, a small scale crowd recognition method based on causality network analysis is proposed. The trajectories of each pedestrians are calculated by covariance tracking to gain the nodes of crowd network. The Granger causality test is used to estimate the relationship between two pedestrians. Based on these causations, two types of complex network are generated which are pair-complex network and group-complex network. Some features of network such as the average path length, betweenness and clustering coefficient are extracted to recognize the six classifications crowd behavior (gather, chat, split, linger, meet and together). Experimental results show that the proposed method can express and recognize crowd behavior effectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 815001 (2015)
Influence of Sample Defocus and Large Thickness on Measurement Error in Machine Vision Application
Lai Xianjia, Xu Wendong, Zhao Chengqiang, and Xiao Yang
Machine vision technology is widely used in industrial measurement. To realize high precision measurement of machine vision is of great significance to precision machining and manufacturing. The problem that measuring object will cause measurement error in machine vision application is studied when it deviates from theMachine vision technology is widely used in industrial measurement. To realize high precision measurement of machine vision is of great significance to precision machining and manufacturing. The problem that measuring object will cause measurement error in machine vision application is studied when it deviates from the focal plane or has a certain thickness. The influence of parallelism error caused by lens telecentricity on measurement error of defocus sample is discussed on emphasis. The experimental results show that among all measurement errors caused by sample deviation from the optimal imaging plane, the proportion of parallelism error accounts for about 90% . Measuring accuracy can be improved greatly by compensating parallelism error. Additionally, in order to analyze the problem that the edge is fuzzy when sample has a large thickness, several edge detection algorithms are used. The results show that within a certain range, the thicker the object is, the larger the edge detection error is. On the basis of this result, a compensation method based on image gray-level curve is put forward. As a result, measurement error has decreased from more than 20 μm to less than 10 μm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 815002 (2015)
Materials
Stable Structure and Spectral Properties of Yn(n=2~10) Clusters
Chen Feilong, Zhai Zhongyuan, Chen Guifang, and Sheng Yong
The possible geometric structures of Yn(n=2~10) clusters are executed with structural optimization and frequency analysis by using the density-functional theory (DFT) B3LYP at the LANL2DZ level. According to the lowest energy principle, the most stable structures without imaginary frequency for Yn(n=2~10) clusters are The possible geometric structures of Yn(n=2~10) clusters are executed with structural optimization and frequency analysis by using the density-functional theory (DFT) B3LYP at the LANL2DZ level. According to the lowest energy principle, the most stable structures without imaginary frequency for Yn(n=2~10) clusters are confirmed. The vibration frequency ωe=188.9 cm-1 of Y2, which is closer to 184.4 cm-1 of experimental data than the earlier calculated results. Based on this, the stability, polarizabilities of Yn(n=2~10) clusters are investigated, and the spectral properties of clusters are introduced. The results indicate that the structure of Y7 is a turning point among the structures of Yn(n＝2~10) clusters. The electronic stability becomes weak with increasing the number of atoms. The vibrational spectra show that the Cs and C2v group have lots of vibration modes, the Y7 and Y9 exhibit better infrared and Raman activity in the respective band and an obvious resonance phenomenon is found..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 816001 (2015)
Preparation of ZnO@SiO2 Core-Shell Quantum Dot and the Fluorescent Properties Research
Huang Wenyi, Wei Huidan, Shi Zhipeng, Bai Dawei, Ma Lanyu, and Li Lijun
A simple, rapid and mild condition method for preparing ZnO@SiO2 core-shell structures quantum dots is reported. Particle sizes，ultraviolet-visible (UV-vis) absorption and emission spectra are characterized using transmission electron microscopy (TEM), ultraviolet spectrometry, fluorescence spectroscopy (FL), nanometerA simple, rapid and mild condition method for preparing ZnO@SiO2 core-shell structures quantum dots is reported. Particle sizes，ultraviolet-visible (UV-vis) absorption and emission spectra are characterized using transmission electron microscopy (TEM), ultraviolet spectrometry, fluorescence spectroscopy (FL), nanometer particle size analyzer and ZETA potentials techniques. The results show that ZnO@SiO2 core- shell structures quantum dots with particles sizes from 3 to 5 nm, it could emit yellow green fluorescence under the excitation of UV- vis light. Its maximum absorption wavelength is 330 nm, whereas the maximum fluorescence emission wavelength is located at 510 nm. The pH, temperature, different metal cations and anion′ s influence on the fluorescence intensity of quantum dots are studied. The results show that when pH≤7, the fluorescence of quantum dots is quenched completely, however, when pH>7, the fluorescence of quantum dots is enhanced with the pH increases, fluorescence intensity reach maximum when pH is 9.0, and then gradually reduce with the increase of pH. Gradually with the increase of temperature fluorescence intensity is reduced, when the temperature is above 50 ℃ fluorescence quenching completely. A valence metal ions has no effect on quantum dot fluorescent intensity, divalent metal ions on the fluorescent weaken degree of order is Fe2+>Mn2+>Cu2+>Pb2+>Co2+>Ba2+>Mg2+ , trivalent metal ions on the fluorescent weaken degree of order is Fe3+＞Cr3+＞Bi3+＞Al3+. Metal ions, such as Fe3+、Fe2+、Bi3+、Cr3+、Mn2+, can make the fluorescence quenching; PO4 3-、HPO4 2-、H2PO4 - ion can make the fluorescence of quantum dots slightly increased; HCO3 -、CO3 2-、CH3COO-、SO3 2- anion can make the fluorescent weaken even quenching; Cl-、SO4 2-、NO3 - ion has no effect on fluorescence almost..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 816002 (2015)
Infrared Supercontinuum Generation in Chalcogencide-Telluritecompound Microstructured Optical Fiber
Wang Cui, Dai Shixun, Yang Peilong, Zhang Peiqing, Wang Xunsi, Liu Zijun, Chen Feifei, Shen Xiang, and Nie Qiuhua
The design of a compound microstructured optical fiber whose core is fabricated with the chalcogenide glass of As2Se3 and cladding made of tellurite glass is presented. The cladding is distributed with two rings of air holes. The dispersion and loss properties of the fiber is studied using a finite element method (FEM)The design of a compound microstructured optical fiber whose core is fabricated with the chalcogenide glass of As2Se3 and cladding made of tellurite glass is presented. The cladding is distributed with two rings of air holes. The dispersion and loss properties of the fiber is studied using a finite element method (FEM). With an adaptive split-step Fourier method-based solver for the generalized nonlinear schrodinger equation (GNLSE), the transmission of a 2.5 μm pump pulse with a width of 200 fs in a 15 cm fiber is numerically simulated. The properties of the infrared supercontinuum spectrum is also studied under different peak powers, pulse widths, and pump wavelengths..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 816003 (2015)
Spectroscopic Investigation of Pr3+ Doped Fluoride Glasses
Zhang Yu, Huang Feifei, Liu Liwan, Zhou Qingling, Xing Zhaojun, Yang ke, and Chen Danping
Pr3 + doped 50ZrF4- 50(BaF2- YF3- AlF3)- x PrF3 fluoride glasses are prepared through hightemperature melt- quenching method, and the properties of photoluminescence and scintillation under different excitation conditions are studied. Experimental results show that when excited by 443 nm blue light, the optimal luminouPr3 + doped 50ZrF4- 50(BaF2- YF3- AlF3)- x PrF3 fluoride glasses are prepared through hightemperature melt- quenching method, and the properties of photoluminescence and scintillation under different excitation conditions are studied. Experimental results show that when excited by 443 nm blue light, the optimal luminous mole concentration of f→f transition (3P0→3H4, 3P0→ 3H6 , 3P0→3F2) is 0.6 % ; when excited by X- rays, the optimal luminous concentration is 1.0 % , and with the increase of Pr3 + concentration, the fluorescence lifetime decreases from 46 ms to 21 ms, concentration quenching effect is quite obvious. The intensities photoluminescence of 4f → 5d transition which locat in the ultraviolet band increase with the Pr3 + concentration. This phenomenon is interpreted as that 4f → 5d transition energy gap is quite large,while the phonon energy of fluoride glass is low, the cross- relaxation requires several phonons, so the concentration quenching effect is too difficult to occur. Under the X- ray excitation, the ultraviolet light doesn′t be detected, while strong 486 nm light emission is generated..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 816004 (2015)
Research on Photoluminescence of Nd3+ Doped NaYF4:Yb,Er/Tm Upconversion Nanoparticles
Ye Shuai, Song Jun, Chen Linchun, Wang Dong, Peng Xiao, and Qu Junle
Strong absorption of 980 nm wavelength light by biological tissues results in the limited application of Yb/Er or Yb/Tm doped NaYF4 upconversion nanoparticles.800 nm excited NaYF4∶Yb,Er/Tm nanoparticles doped with Nd3 + ions are reported.By comparing the photoluminescence spectra of different structured nanoparticles iStrong absorption of 980 nm wavelength light by biological tissues results in the limited application of Yb/Er or Yb/Tm doped NaYF4 upconversion nanoparticles.800 nm excited NaYF4∶Yb,Er/Tm nanoparticles doped with Nd3 + ions are reported.By comparing the photoluminescence spectra of different structured nanoparticles incorporated with Nd3 + ions,it is found that the emission intensity by 800 nm laser of core/shell structured NaYF4∶Yb3 + 20%,Er3 + 2%@NaYF4∶Nd3 + 20% nanoparticles is the highest,which is close to the emission intensity of NaYF4∶Yb3 + 20% ,Er3 + 2% nanoparticles excited by 980 nm laser.The emission intensity is enhanced by more than 600 times compared with that of NaYF4∶Yb3 + 20%,Er3 + 2%,Nd3 + 20% nanoparticles.It is proved that the quench effect due to Nd incorporation is mainly related to the interaction between Nd3 + ions and the sensitizer Yb3+ ions,but not that between Nd3+ ions and the activator Er3+/Tm3+ ions..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 816005 (2015)
Medical Optics and Biotechnology
Study on Variation in Cortex Oxygen with Task Features Using Functional Near-Infrared Spectroscopy
Pan Jinjin, Jiao Xuejun, Jiao Dian, Wang Chunhui, Xu Fenggang, Jiang Jing, Zhang Zhen, and Cao Yong
Functional near-infrared spectroscopic (fNIRS) imaging is an emerging optical brain imaging technique.Numerous studies have been carried out for assessment of mental workload in simple tasks by fNIRS ,but these methods can not be directly applied when the experimental task is complex and integrated.A task decompositionFunctional near-infrared spectroscopic (fNIRS) imaging is an emerging optical brain imaging technique.Numerous studies have been carried out for assessment of mental workload in simple tasks by fNIRS ,but these methods can not be directly applied when the experimental task is complex and integrated.A task decomposition idea is tried to study the variation in cortex blood oxygen with every task feature of complex task using fNIRS,and to find ideas and basis for mental workload assessment in complex tasks.The results show that the activation degree of oxygenated hemoglobin (HbO) in prefrontal cortex (PFC) area makes response to the change of complexity,time pressure,and with or without control strongly;the area of visual cortex (VC) has strong activation degree as the feature of time pressure changes,but weak activation for complexity and with or without control;motor cortex (MC)has strong activation degree with the feature of control existing or not,but its relationship with the change of complexity and time pressure is weak..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 817001 (2015)
Nonlinear Optics
Related Factors of Interactions between Nonlocal Spatial Solitons
Zhu Yeqing, and Hu Wei
There are many factors influencing the interactions between nonlocal spatial solitons.It is showed that the interactions of two spatial solitons in nematic liquid crystals are dependent on phase and bias voltage by numerical simulation and experimental tests.Based on the nonlocal nonlinear Schro?dinger equation (NNLSE)There are many factors influencing the interactions between nonlocal spatial solitons.It is showed that the interactions of two spatial solitons in nematic liquid crystals are dependent on phase and bias voltage by numerical simulation and experimental tests.Based on the nonlocal nonlinear Schro?dinger equation (NNLSE),numerical calculation is carried out by Fourier transform method.And then the influence of phase difference on interactions between nonlocal spatial solitons is analyzed in detail.By experimentally investigating the interaction properties of two solitons in nematic liquid crystals in different incident conditions,the relationship between the position of crosspoint and the bias voltage are got..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 819001 (2015)
Two-Stage Noncollinear Optical Parametric Amplification Approaching Single Cycle
Wang Yanhai
A new two- stage noncollinear phase- matching optical parametric amplification (OPA) scheme,which can make full use of the phase- matching capability and the spectral gain range of specific nonlinear crystal to amplify neighboring spectral components of the seed by using individual phase- matching geometry in two- stagA new two- stage noncollinear phase- matching optical parametric amplification (OPA) scheme,which can make full use of the phase- matching capability and the spectral gain range of specific nonlinear crystal to amplify neighboring spectral components of the seed by using individual phase- matching geometry in two- stage OPAs,is proposed to achieve a gain bandwidth close to one octave bandwidth.Numerical simulations are performed,in the case of a 4.5 mm- thick β - BaB2O4 (BBO) crystal and a laser pump source with wavelength of 532 nm and intensity of 5 GW/cm2.The results show that this scheme allows for an amplification of 480 nm spectral width spanning from 710 nm to 1190 nm corresponding to 0.75 octave bandwidth with a Fourier limited pulse duration of 5 fs,which equals to 1.6 times of the period of light oscillation.The phase distortions from parametric gain process and its impact on the temporal profile of the recompressed signal pulse are calculated.Results presented are capable of providing a theoretical basis for the design of optical parametric amplification system allowing for the generation of single-cycle pule..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 819002 (2015)
Optical Design and Fabrication
System Integration and Control of the Hydrostatic Supports for Manufacturing Ultra-Large Optics
Hu Haifei, Luo Xiao, Qi Erhui, Hu Haixiang, and Zheng Ligong
In the process of manufacturing ultra-large mirrors,there is very limited space beneath the mirror′s back,the machine platform has limited carrying capacity,so the polishing support system (PSS) should be structured simply.Also as the mirror is suffering from fabricating load and polishing powder which is very“dirty”spIn the process of manufacturing ultra-large mirrors,there is very limited space beneath the mirror′s back,the machine platform has limited carrying capacity,so the polishing support system (PSS) should be structured simply.Also as the mirror is suffering from fabricating load and polishing powder which is very“dirty”spreads everywhere,PPS should not be sensitive to polishing load and its working environment.Moreover,when one wants to speed up the polishing through online testing,PPS should be adjustable and stable enough.An equalforce hydrostatic support system is designed,afterward the equal-force performance and static stiffness of PSS′s single support structure are tested,then the print-through effect is predicted,finally the corresponding control method is proposed and PPS is integrated with (GUI) operation.Applied to the polishing of a 2 m SiC mirror,PPS restricts the magnitude of print-through effect to 13.1 nm≈l/48,which is considered stiff enough.And PPS achieves an angle adjusting region of 0.34″~0.48° and a ±5 mm motion along Z axis for the mirror.The angle adjustment makes the corresponding XY-plane motion of the curvature center range from 50 mm to 10 mm,which is close to the size of charge couple device (CCD)′s basic unit,showing it suitable for mirror adjustment during vertical testing.The proposed hydrostatic support system has a good adaptability to 2~4 m class mirrors,which are in great demand..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 822001 (2015)
Optical Design of Spaced-Based Broadband Limb Ozone Profile Sounder
Xue Qingsheng
Space-based broadband limb ozone profile remote sensing is a new type space optical remote sensor. Based on the requirements of broadband, large dynamic range, a new method of sounding the broadband limb imaging spectrum simultaneously is proposed. The method uses a filter to change the intensity of entrance signal. UsSpace-based broadband limb ozone profile remote sensing is a new type space optical remote sensor. Based on the requirements of broadband, large dynamic range, a new method of sounding the broadband limb imaging spectrum simultaneously is proposed. The method uses a filter to change the intensity of entrance signal. Using an off-axis parabolic telescope and off-axis aspheric spectral imaging system, broadband limb ozone profile sounder is designed, which uses a prism as a dispersive element. The working waveband is from 290 nm to 1000 nm, the field of view of is 1.4°×0.032°, the focal length is 80 mm, and the relative aperture is 1/6. Optimization design and performance evaluation are performed by ZEMAX-EE software. The maximum of root mean square for spot radius is 6.2 mm, and less than half size of pixel. The spectral resolution is 0.9 nm at 290 nm, the spectral resolution is 22 nm at 1000 nm, and both of them satisfy the requirement of specification. The modulation transfer function for different wavelengths of limb ozone profile sounder is more than 0.82 at characteristic frequency 7.4 lp/mm. The design results satisfy the requirements of imaging quality, the volume is small, the mass is low, and it is suitable for the application of space-based remote sensing..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 822002 (2015)
Aberration Automatic Design of Continuous Zoom Optical System
Ma Yingjun, Zhang Bao, and Hong Yongfeng
In the process of continuous zoom optical system design, the aberration automatic design demands prior experience , complicated algorithm and massive calculation. In order to overcome these difficulties, the method of using subtractive linear equations to carry out the aberration automatic design is proposed. With thisIn the process of continuous zoom optical system design, the aberration automatic design demands prior experience , complicated algorithm and massive calculation. In order to overcome these difficulties, the method of using subtractive linear equations to carry out the aberration automatic design is proposed. With this method, a continuous zoom optical system of visible spectrum is designed. Using Gaussian optics to calculate the paraxial structural parameters of the system; the application of subtractive linear equations in the aberration automatic design make the value of primary aberration coefficients SI , SII and SIII approximately equal at different focal lengths positions; based on the results of the aberration automatic design, the initial structural parameters of system are calculated; the aberrations are corrected by Zemax optical design software. The design result indicates that the focal length could vary from 20 mm to 300 mm continuously for this system and the modulation transfer function is always bigger than 0.4 at the spatial frequency of 50 lp/mm and every focal length position. In conclusion, the method of subtractive linear equations in the aberration automatic design can simplify the calculation, reduce the degree of relying on the prior experience and achieve high quality of image..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 822003 (2015)
Remove Trefoil Aberration of Project ObjectiveUsing Lens Surface Re-Polishing Technology
Zhao Yang, Wang Ping, S.hi Zhenguang, Gu Yongqiang, Liu Chunlai, and Men Shudong
It is impossible to remove the high order aberrations of minimum aberration project objective only with adjustable structures,which is a bottleneck to restrain further optimization.Ion beam figuring (IBF)instrument is widely used in optical lens manufacturing.IBF can well control low and middle frequency figuring errorIt is impossible to remove the high order aberrations of minimum aberration project objective only with adjustable structures,which is a bottleneck to restrain further optimization.Ion beam figuring (IBF)instrument is widely used in optical lens manufacturing.IBF can well control low and middle frequency figuring errors to obtain high accuracy figuring polish.The wavefrint error of projection lens small scale model is analyzed using fringe Zernike polynomials,which contains a large amount trefoil aberration.One surfaces of the objective is chosen to remove designated figures using IBF to compensate trefoil aberration of the whole system.Simulation and experiment results show that trefoil aberration is well controlled,and the wavefront error is reduced from 29.6 nm (RMS) to 12.7 nm (RMS).The quality of objective is greatly improved,which proves the corrextness and applicability of this trefoil aberration compensating method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 822004 (2015)
Optical Design of Spaceborne Directional Polarization Camera
Yang Weifeng, Hong Jin, and Qiao Yanli
Spaceborne directional polarization camera is a super-wide-angle polarization and low-distortion imaging sensor.First,the working principle of the spaceborne directional polarization camera has been introduced.In order to guarantee the requirements of polarization measurement accuracy and the wide field of view imagingSpaceborne directional polarization camera is a super-wide-angle polarization and low-distortion imaging sensor.First,the working principle of the spaceborne directional polarization camera has been introduced.In order to guarantee the requirements of polarization measurement accuracy and the wide field of view imaging quality,the design difficulties of the optical system have been analyzed and finally a retro- type image side telecentric optical structure has been adopted.Due to the aberration characteristics of the optical path structure,aspheric lens has been used to correct distortion and astigmatism which improves the uniformity of the image plane illuminance.Depending on this method,ray tracing and optimization for spaceborne directional polarization camera has been used by the optical design software.The spectral range is 420~930 nm.The whole field of view angle is 118.74°.The focal length is 4.833 mm.The relative aperture is 1:4.The result shows that the modulation transfer function (MTF) of the optical system in the whole field of view is greater than 0.5@22.22 lp/mm,the maximum distortion is 0.9669% and the degree of surface unevenness of image is higher than 97%.After mounting,aligning and fabricating,the image quality of optical system completely satisfies the requirements..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 822005 (2015)
Simulation Model of Mask with Defect and Its Application to Defect Compensation in Extreme-Ultraviolet Lithography
Liu Xiaolei, Wang Xiangzhao, and Li Sikun
A fast model is proposed for simulation of mask with defect based on single surface approximation in extreme-ultraviolet (EUV) lithography. In this model, the impact of defect on the reflection of the multilayer is calculated by phase perturbation and amplitude attenuation. Diffraction of the absorber is calculated by A fast model is proposed for simulation of mask with defect based on single surface approximation in extreme-ultraviolet (EUV) lithography. In this model, the impact of defect on the reflection of the multilayer is calculated by phase perturbation and amplitude attenuation. Diffraction of the absorber is calculated by using the modified thin mask model. Taking 22 nm contact holes with pitch of 60 nm as example, compared with the waveguide method, the computation speed of the proposed model is increased more than 10 times and the critical dimension (CD) error is less than 0.6 nm. The optimal modification size for the compensation of defect is calculated by the proposed model and the result is same to that calculated by the waveguide method. Moreover, the concept of defect compensability is proposed for different defect sizes, and the defect compensability of 2D mask is discussed by using the proposed model..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 822006 (2015)
0.4~1.7 μm Wideband Fast F-Number Optical System Design
Qu Rui, Deng Jian, Peng Xiaole, and Cao Xiaohe
Table comparison of dispersive character is made between some frequently used optical glasses in visible (Vis), near-iinfrared (NIR) and short-wave infrared (SWIR). Through comparison, different dispersive characters of these optical glasses in different waveband arepointed out. Then, a kind of using and interchanging Table comparison of dispersive character is made between some frequently used optical glasses in visible (Vis), near-iinfrared (NIR) and short-wave infrared (SWIR). Through comparison, different dispersive characters of these optical glasses in different waveband arepointed out. Then, a kind of using and interchanging method of these materials especially in optical design process is discussed. Based on this method and apochromatic model, a wideband (Vis-SWIR) fast F-number optical system under the requirements of F/1.4, focal length of 70 mm, whole field of view of 6.3°×8.1°, waveband of 0.4~1.7 μm is designed with optical passive athermalization technology. Except the sphere dome, the optical system, which uses 4 kinds of optical glass, consists of 9 lenses, total length of 110 mm, has good image quality and tolerance character at -45 ℃~60 ℃..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 822007 (2015)
Optical Devices
Tunable Cylindrical Liquid Lens Array for 2D/3D Switchable Display
Zhao Wuxiang, Wang Qionghua, and Li Lei
A tunable cylindrical liquid lens array for two dimensional (2D)/three dimensional (3D) switchable display is proposed. It mainly contains two transparent liquids of different refractive index: liquid 1 and liquid 2. Liquid 1 and liquid 2 are divided by a transparent elastic membrane. The elastic membrane is supported A tunable cylindrical liquid lens array for two dimensional (2D)/three dimensional (3D) switchable display is proposed. It mainly contains two transparent liquids of different refractive index: liquid 1 and liquid 2. Liquid 1 and liquid 2 are divided by a transparent elastic membrane. The elastic membrane is supported by a micro-clapboard array. Driving these two liquids to flow and the support of micro-clapboard array can change the shape of the elastic membrane, then, the membrane has two shapes as flat shape and tunable cylindrical shape. The focal length of tunable cylindrical liquid lens array extensively adaptive from infinity to a certain positive value is realized. A tunable cylindrical liquid lens array prototype for 2D/3D switchable display is developed. The experimental result proves the prototype′ s tunable focus length ability. The prototype with a matched flat display panel realizes autostereoscopic 3D display, moreover, the elastic membrane can change to flat for regular 2D display. Therefore, 2D/3D switchable display is realized..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 823001 (2015)
Optics at Surfaces
Spontaneous Emission Properties of Emitters in Dielectric-Loaded Surface Plasmon Polariton Waveguide
Yao Bo, Liu Ye, Long Hu, and Mao Qinghe
The spontaneous emission properties of emitters in dielectric-loaded surface plasmon polariton (DLSPP)waveguide are investigated.The expressions for both the spontaneous emission rate and the probability of spontaneous emission coupled into SPP mode of an emitter in SPP waveguide are derived with a dipole approximationThe spontaneous emission properties of emitters in dielectric-loaded surface plasmon polariton (DLSPP)waveguide are investigated.The expressions for both the spontaneous emission rate and the probability of spontaneous emission coupled into SPP mode of an emitter in SPP waveguide are derived with a dipole approximation.Then,the spontaneous emission rate and the probability of spontaneous emission coupled into SPP mode of the rhodamine 6G (R6G) particle in the single-mode DLSPP waveguide are calculated numerically.The results show that the spontaneous emission rate of the particle increases when the particle is near the metal interface while decreases and inclines to the value in the vacuum when the particle is away from the metal interface.Meanwhile,the probability of spontaneous emission coupled into SPP mode is also position-related,and may reach about 70% when the particle is located in the center part of the cross-sectional area of the waveguide.With those simulation results,it may be predicted that both the maximum achievable average population inversion and the efficiency of spontaneous emission coupled into SPP mode of the particles over the cross-sectional area of the waveguide may be improved by optimizing the particle-doped distribution..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 824001 (2015)
Optics in Computing
Optimal Design Method of Integrated Fiber Optic Probe for Dynamic Light Scattering
Liu Wei, Xiao Yu, Wang Yajing, Ma Lixiu, and Shen Jin
Fiber optic probe is made up of two single mode fibers,one for launch and the other for detection,mounted on one gradient index (GRIN) micro lens.It can replace the optical path of the conventional dynamic light scattering set- up and accord with spatial coherence condition.However,there is a lack of the optimal designFiber optic probe is made up of two single mode fibers,one for launch and the other for detection,mounted on one gradient index (GRIN) micro lens.It can replace the optical path of the conventional dynamic light scattering set- up and accord with spatial coherence condition.However,there is a lack of the optimal design method of structural parameters of optical fiber probe.Based on spatial coherence condition of the dynamic light scattering system,we analyze the structural parameters of the optical fiber probe,describe the method of optimal design and determine the best value range of the distance and angle between two lens of optical fiber probe.Experimental data shows that the optical fiber probe,whose angle between two lens is 19° and space is 1.5 mm,can meet the requirement of the spatial coherence.In such a case,the signal-to-noise ratio of the received signal is highest and intercept of the correlation function is 0.83.The relative error of the average particle diameter,which is obtained by the optimal fitting Cumulants method,is less than 2%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 829002 (2015)
OPTOELECTRONICS
CRLB Feature of Optoelectronic Device and a Comparison of the Locating Errors for Centroiding Algorithms
Zhang Jun, Hao Yuncai, Long Ye, and Liu Da
In the positioning procedure for point- like sources generated in optoelectronic devices,Cramer-Rao Lower Bound (CRLB) is used to estimate the locating accuracy of the devices contaminated with noise.As the lower bound of any unbiased estimator,CRLB is known as a criterion to assess whether an estimator meets the charaIn the positioning procedure for point- like sources generated in optoelectronic devices,Cramer-Rao Lower Bound (CRLB) is used to estimate the locating accuracy of the devices contaminated with noise.As the lower bound of any unbiased estimator,CRLB is known as a criterion to assess whether an estimator meets the characteristics of minimum variance unbiased (MVU).The CRLB characteristies on the performance of the imaging device under both Poisson and Gaussian noise are given and accordingly the positioning error of three current centroiding algorithms,center of gravity (COG),iteratively weighted center of gravity (IWCOG) and Gaussian least squares fitting(GLSF),is investigated respectively.Theoretical analysis and simulation results show that IWCOG and GLSF share the same position error and reach CRLB of optoelectronic imaging device,thus meet MVU features.That is to say,COG makes the biggest positioning error,followed by IWCOG and GLSF.And the computing time of IWCOG is just several times longer than COG algorithm,while GLSF algorithm is certainly the time-consuming procedure to make it inapplicable on-board on star tracker.IWCOG is proven to be as a method with low error,real- time and robust algorithm,making it possible for highprecision condition such as star tracker,Shack-Hartmann sensor..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 825001 (2015)
Physical Optics
Polarization Modelling of Coude Optics and Vacuum Window for the New Vacuum Solar Telescope
Liu Weiwei, Yuan Shu, and Jin Zhenyu
An important scientific task of new vacuum solar telescope (NVST) is to obtain the middle and lower magnetic field of solar by accurate polarization measurement.In order to achieve high precision and high efficiency systematic polarization calibration,it is needed to build a polarization model for the telescope.This arAn important scientific task of new vacuum solar telescope (NVST) is to obtain the middle and lower magnetic field of solar by accurate polarization measurement.In order to achieve high precision and high efficiency systematic polarization calibration,it is needed to build a polarization model for the telescope.This article analyzes the telescope instrumental polarization changes of coude optical path over days and seasons,and birefringence effects of its vacuum window.The result shows:the main crosstalk of Coude optical path is between linear polarization and circuit polarization,whose maximum number is 0.7.In the meantime,when the sun approaches midheaven around the summer solstice,the curve of crosstalk becomes shocked since dramatic derotation.And the total polarization property of vacuum window is equivalent to a retarder which changes along with the altitude of telescope.It becomes obvious when the telescope points are horizontal and the crosstalk increases to 1.2 × 10-2 ..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 826001 (2015)
Generating and Modulating Orbital Angular Momentum Beams by Metasurface
He Shimei, and Shu Weixing
A new approach is proposed to enable a beam to carry orbital angular momentum (OAM) and manipulate the OAM of vortex beams by using metasurface. In the evolution of the polarization state, the light field can acquire a Pancharatnam-Berry(PB) geometric phase. Then it is possible to obtatin a desired phase by manipulatinA new approach is proposed to enable a beam to carry orbital angular momentum (OAM) and manipulate the OAM of vortex beams by using metasurface. In the evolution of the polarization state, the light field can acquire a Pancharatnam-Berry(PB) geometric phase. Then it is possible to obtatin a desired phase by manipulating the polarization of light. The metasurface constructed in this paper has a distribution of spatially varying optical axes, and can manipulate the polarization of light accurately. Particularly, if the optical axis orientation of metasurface changes continuously along the azimuth direction, an azimuth-dependent PB phase, i.e. a vortex phase, will be imparted to the beam. Such a phase can be used to enable a beam to carry OAM and tune the OAM of a vortex beam. Further experiments verify the theoretical results. The results provide a new way to generate OAM beams and modulate their OAM, which is expected to have potential applications in quantum communication and optical micromanipulation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 826002 (2015)
Quantum Optics
Nanomechanical-Resonator-Assisted Induced Optical Switching in Quantum Dot System
Zhong Wenxue, Wang Yiping, and Cheng Guangling
Optical switching behavior is presented for the weak probe field applied to the solid-state quantum dot system,which is driven by a strong control field and is coupled with a single nanomechanical resonator.The research results show that it is possible to change the coupling strength of quantum dots with nanomechanicalOptical switching behavior is presented for the weak probe field applied to the solid-state quantum dot system,which is driven by a strong control field and is coupled with a single nanomechanical resonator.The research results show that it is possible to change the coupling strength of quantum dots with nanomechanical resonator to control optical switching when the driving field is detuned from the quantum dot.It is found that the behavior of optical switching can be obtained via modulating the Rabi frequency of the control field at the presence of the nanomechanical resonator,The responsible physical mechanism is the existence of auxiliary energy levels with the help of the nanomechanical resonator and the occurrence of electromagnetically induced transparency via the control field.The adopted solid-state quantum system plays an extremely important role in the macroscopic quantum state and the optical switching in such a system has the potential applications in optical communications,photonics and nonlinear optics..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 827001 (2015)
Remote Sensing and Sensors
Design and Research of Diffuser Panel Used for on-Board Calibration
Shi Jiading, Zhang Liming, Cao Xingjia, Xu Weiwei, Han Huida, and Wang Jixiang
Reflective solar bands are calibrated on orbit by a solar diffuser(SD) panel. The SD panel plays an important role in a set of on-board calibrator. Its reliability of the structure design will directly affect the accuracy of the on-board calibrator. In order to get the response situation of the calibration diffuse reflReflective solar bands are calibrated on orbit by a solar diffuser(SD) panel. The SD panel plays an important role in a set of on-board calibrator. Its reliability of the structure design will directly affect the accuracy of the on-board calibrator. In order to get the response situation of the calibration diffuse reflection plate structure under space mechanical condition, vibration test on SD panel is processed. In the test, the data on the frequency of the SD panel structure and the dynamic response are got by stochastic load test method. Meanwhile, the optical properties of the SD panel: hemispherical reflectance direction(DHR) and the bi-directional reflectance distribution function (BRDF) are measured. The results show that the frequency of the structure can meet the design requirements (more than 120 Hz), high reflectance(more than 99%), spectral flatness and good Lambertian scattering properties in reflectance, which are basic requirements for space applications..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 828001 (2015)
Scattering
Study on Difference Field Scattering Properties between Slightly Rough Optical Surface and above Redundant Particles
Gong Lei, Wu Zhensen, Dai Shaoyu, and Li Zhengjun
Based on the wavelet method of moment (MOM),difference field scattering properties between slightly rough optical surface and redundant particles above are researched.The integral equations about slightly rough optical surface and redundant particles are presented from basic electric field integral equations.Impedance Based on the wavelet method of moment (MOM),difference field scattering properties between slightly rough optical surface and redundant particles above are researched.The integral equations about slightly rough optical surface and redundant particles are presented from basic electric field integral equations.Impedance matrix,composite scattering field and difference scattering field are obtained.Bistatic radar cross section calculation formula of the composite scattering model is given.Bistatic radar cross section and difference bistatic radar cross section are analyzed between different material one/double redundant particles and slightly rough optical surface with different incident angle and numerical experiments are shown.The scattering contribution and difference field scattering angular distribution of the redundant particles or rough optical surface are provided..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 829001 (2015)
Study of Laser Scattering Characteristics of Rough Sea Surface with Foams
Qi Xiao, and Han Xiang′e
The blue-green laser penetrates the sea surface in submarine communication and detection, and its propagation through atmospheric-sea characteristics is influenced by wind speed and other acting force. Based on the volume-surface composite model of rough sea surface with foam layer driven by wind,the rough surface scatThe blue-green laser penetrates the sea surface in submarine communication and detection, and its propagation through atmospheric-sea characteristics is influenced by wind speed and other acting force. Based on the volume-surface composite model of rough sea surface with foam layer driven by wind,the rough surface scattering theory, Mie theory and vector radiative transfer (VRT) theory, the laser scattering characteristics of rough sea surface are analyzed. Using Kirchhoff approximation for the JONSWAP spectrum, the dependence of the backscattering coefficient of the sea surface on the incident angle,the wind speed, the wind area, as well as the temperature and salinity are discussed. The results suggest that foam layer has a considerable effect on the scattering characteristics especially at large incident angle, with the increasing wind speed, wind area and the dielectric constant..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 829003 (2015)
Spectroscopy
Accurate Age Estimation of Bloodstains Based on Visible Reflectance and Genetic Algorithm Interval Partial Least Squares
Dong Yongfang, Meng Yaoyong, Zhang Pingli, Wen Wei, and Li Na
Accurate age estimation of bloodstains can provide enormous forensic value. Visible reflectance spectroscopy technique combined with partial least squares (PLS) is applied to accurately estimate the age of bloodstains for forensic purposes. Genetic algorithm (GA) combined with PLS is used to select the most efficient sAccurate age estimation of bloodstains can provide enormous forensic value. Visible reflectance spectroscopy technique combined with partial least squares (PLS) is applied to accurately estimate the age of bloodstains for forensic purposes. Genetic algorithm (GA) combined with PLS is used to select the most efficient spectral intervals. The genetic algorithm interval partial least squares (GA- iPLS) models built in the optimal intervals, present better predictive capability than full-spectrum PLS model. GA-iPLS can validly select desirable intervals and improve predictive ability. Considering the effect of the specificity of bloodstains on models, the GAiPLS models built in age period from 2.00 h to 48.00 h and in age period from 48.00 h and 1080.00 h are achieved with correlation coefficient (Rp) of 0.9949/0.9924, root-mean-square error of prediction (RMSEP) of 1.59 h/43.56 h , residual predictive deviation (RPD) of 10.32/8.4243 respectively, which can be used to accurately predict the age of bloodstains from 2.00 h to 1080.00 h instead of GA-iPLS model in 2.00~1080.00 h. The results demonstrate that visible reflectance spectroscopy combined with GA-iPLS will be a reliable tool to accurately estimate the age of bloodstains for forensic practical applications..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 830001 (2015)
Towards Universal Evaluation Method for Color Quality of Light Sources
Zhang Fuzheng, Xu Haisong, Wu Xiaomin, and Cai Jianqi
Commission internationale de I′Eclairage (CIE) color rendering index has many deficiencies when applied to evaluating color quality of new-type light sources such as light emitting diode (LED). The universal evaluation method of light source color quality is discussed, which can play a vital role in contributing to theCommission internationale de I′Eclairage (CIE) color rendering index has many deficiencies when applied to evaluating color quality of new-type light sources such as light emitting diode (LED). The universal evaluation method of light source color quality is discussed, which can play a vital role in contributing to the application of new-type light sources. 16 typical indexes are adopted to evaluate different types of illuminants and light sources in the experiment. The results indicate that most indexes are correlated with each other, and color fidelity based and gamut based methods are proposed to totally evaluate the color quality of light sources. An attempt is made and further verified to construct a comprehensive index of color quality for evaluating light sources..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 833001 (2015)
Thin Films
Transparent Shielding Film Based on the Metallic Photonic Crystal
Zhao Yali, Li Kexun, Li Xufeng, Zhang Qingcui, Ma Fuhua, Zhang Dewei, and Wei Xuehong
Shielding effectiveness and optical transmittance are conflict in the preparation process of electro magnetic (EM) shielding and transparent film by indium tin oxide (ITO) film and metal mesh. Thus the compatibility of shielding effectiveness and light transmittance can be improved by the solution of the conflict amongShielding effectiveness and optical transmittance are conflict in the preparation process of electro magnetic (EM) shielding and transparent film by indium tin oxide (ITO) film and metal mesh. Thus the compatibility of shielding effectiveness and light transmittance can be improved by the solution of the conflict among metal shielding, conductive and transparent. Transparent shielding film based on the metallic photonic crystal is proposed and experimentally demonstrated. The ITO/Ag periodic structured metallic photonic crystal transparent film is prepared by magnetron sputtering. The influences of the shielding effectiveness(SE), optical transmittance and the sheet resistance on the samples are studied. With the increasing of unit cycle metal film thickness, optical light transmittance in 600~800 nm wavelength is reduced by more than 10%. At the same time, the optical transmission spectra becomes narrower. But the light transmittance in 400~600 nm wavelength does not decrease with the increasing of metal film thickness, and even increased. With the increase of metal film thickness, shielding effectiveness is improved in microwave, sheet resistance reduces. Through the experiment, a different conclusion is drawn that the photonic crystal film shielding effectiveness does not totally depend on photonic crystal metal film thickness. The results show that the shielding effectiveness is as high as 70 dB, optical transmittance is greater than 50%, sheet resistance is lower to 2.1 Ω..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 8, 831001 (2015)
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