Contents
2015
Volume: 35 Issue 11
43 Article(s)
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Atmospheric Optics and Oceanic Optics
Retrieval of Aerosol Profile Based on the Ring Effect Observed by MAX-DOAS
Mou Fusheng, Xie Pinhua, Li Ang, Wang Yang, Wu Fengcheng, Chen Hao, Xu Jin, and Zhang Jie
Ring effect is defined as the phenomenon that the depth of solar Fraunhofer lines in scattered light shallows (is filled up) and is caused by rotational Raman scattering by atmospheric O2 and N2 molecules. Aerosol can change the atmospheric light path of photons and atmospheric scattering properties, and then influenceRing effect is defined as the phenomenon that the depth of solar Fraunhofer lines in scattered light shallows (is filled up) and is caused by rotational Raman scattering by atmospheric O2 and N2 molecules. Aerosol can change the atmospheric light path of photons and atmospheric scattering properties, and then influence the scattering number and Roman scattering possibility, so the aerosol information can be retrieved from the observation of Ring effect. A new method for determining aerosol profile by ground- based multi axis differential optical absorption spectra(MAX-DOAS) observation is studied. Aerosol extinction profile information can be obtained through the MAX-DOAS observation under clear days and combination with McArtim.The comparison between retrieval result and measurement result from sunphotometer has a good agreement. The results show the retrieval of aerosol profile from Ring effect observed by ground-based MAX-DOAS is feasible..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1101001 (2015)
Infrared Atmospheric Visibility ：Definition ,Algorithm and Analysis of Key Factors
Zhang Jingwei, Wu Pengfei, and Rao Ruizhong
Usually, atmospheric visibility is used to describing the atmosphere′s visual effects in the visible light, but it does not apply to infrared wavelengths. In view of the visualized characteristics of atmospheric visibility and the pressing needs of the infrared electric technology, based on the infrared system contrastUsually, atmospheric visibility is used to describing the atmosphere′s visual effects in the visible light, but it does not apply to infrared wavelengths. In view of the visualized characteristics of atmospheric visibility and the pressing needs of the infrared electric technology, based on the infrared system contrast threshold, referring to the definition of visible light atmospheric visibility, the concept of infrared atmospheric visibility is put forward. According to the definition presented here and the physical process of infrared atmospheric transmittance involved in, the key determinants factors of infrared atmospheric visibility are analyzed. Generally, these factors are atmospheric visibility of visible light, absolute humidity and aerosol types. the quantitative relationship between the infrared atmospheric visibility and these factors is estabished, and the infrared atmospheric visibility of atmospheric windows (1.06,3~5,8~12μm)is calculated, whose noise equivalent temperature difference (NETD) is 0.05 K..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1101002 (2015)
A New Water Chlorophyll-a Index and Analysis of Its Application Potential
Guo Yulong, Li Yunmei, Wang Qiao, Zhu Li, and Lü Heng
A chlorophyll-a spectrum index (CSI) is built based on the linear spectral unmixing method using the endmembers selected from in situ spectra. The character of CSI is analyzed based on a dataset including 307 samples collected from the Taihu Lake, Chaohu Lake, Dianchi Lake, and the Three Georges Reservoir. Furthermore,A chlorophyll-a spectrum index (CSI) is built based on the linear spectral unmixing method using the endmembers selected from in situ spectra. The character of CSI is analyzed based on a dataset including 307 samples collected from the Taihu Lake, Chaohu Lake, Dianchi Lake, and the Three Georges Reservoir. Furthermore, a chlorophyll-a concentration (Cchla) estimation model is built and compared with traditional models in terms of noise immunity and sensor adaptability. The results show that: 1) CSI is a good indicator for Cchla. Two spectrum sets that are divided by fCSI=0 clearly show different spectrum characteristics; 2) for the hyperspectral dataset, the CSI algorithm gets similar performance to that of the three band algorithm (TBA) (their validation mean absolute percent errors are 0.332 and 0.330, respectively, root mean squares errors are 9.892 and 9.929, respectively); 3) the CSI algorithm is not sensitive to both unbiased and biased noise. Its accuracy is nearly independent on the unbiased noise. Meanwhile, the traditional three band algorithm is sensitive to both of the two kinds of noise; 4) the CSI algorithm is less sensitive to the band settings of the remote sensor than the traditional algorithms. The advantage is more obvious for wide band multispectral sensors. Compared with traditional Cchla semi-empirical models, the CSI algorithm is more stable and potential..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1101003 (2015)
Simulation of Atmospheric Aerosol Particle Absorption Characters Based on Photo-Thermal Interferometry
Li Shuwang, Shao Shiyong, Mei Haiping, and Rao Ruizhong
The absorption of atmospheric aerosol particle is weak, but it affects earth′s radiation balance and atmospheric high energy laser transfer, so its precise measurement is paid more and more attention. By the analysis alteration of temperature distribution and refractive index which induced by pumping laser, the relatioThe absorption of atmospheric aerosol particle is weak, but it affects earth′s radiation balance and atmospheric high energy laser transfer, so its precise measurement is paid more and more attention. By the analysis alteration of temperature distribution and refractive index which induced by pumping laser, the relationship of photo-thermal phase, effective absorption coefficient and excited time is deduced. Then phase generated carrier (PGC) algorithms for measuring phase change information is declared. It is also calculated that several photothermal effect of three typical aerosols with different absorbing capabilities which irradiated by pumping laser at two wavelengths. Then, the superiority of PGC algorithms is displayed, including its demodulation precision and noise elimination with calculation and error analysis. The experimental research of PGC algorithms is done..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1101004 (2015)
Experimental Study on Beam Wander of Collimated Beam in Atmospheric Turbulence Under Sea Surface Environment
Wang Hongxing, Wu Xiaojun, and Song Bo
Beam wander is an important effect when a beam propagates in atmospheric turbulence. A set of measurements of beam wander of collimated beam using CCD techniques are conducted under the sea surface environment in Yantai region, and the characteristics are analyzed based on the measured data. Results show that the beam Beam wander is an important effect when a beam propagates in atmospheric turbulence. A set of measurements of beam wander of collimated beam using CCD techniques are conducted under the sea surface environment in Yantai region, and the characteristics are analyzed based on the measured data. Results show that the beam wander is larger in the horizontal direction than in the vertical direction, and the amplitude in horizontal direction is between 5.25 mm and 10.69 mm, and in vertical varies from 4.45 mm to 8.59 mm for a 1.21 km optical path. The mean ratio between the standard deviation in two directions is 1.33, and is lower than the value in other environments. The difference between the beam wander in two directions reduces with the increasing propagation distance, and the ratio is larger in nigthttime than in daytime. The beam wander keeps stable at different times. In addition, atmospheric refractive index structure parameter is also analyzed during the test period..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1101005 (2015)
Contribution of the Surface Layer to the Integral Turbulence in Northwest Plateau
Chen Xiaowei, Sun Gang, Liu Qing, Li Xuebin, and Weng Ningquan
Results from experiments measuring surface layer turbulence in Northwest China are presented. The measurements are taken over two years using surface layer atmospheric parameter system and differential image motion monitor.The surface layer atmospheric parameter system is composed of HTP-2 microthermal sensors and WXT5Results from experiments measuring surface layer turbulence in Northwest China are presented. The measurements are taken over two years using surface layer atmospheric parameter system and differential image motion monitor.The surface layer atmospheric parameter system is composed of HTP-2 microthermal sensors and WXT520 meteorological sensorsis placed at 2 m and 6 m on a mast. Microthermal sensors are used to measure structure constant of refractive index and meteorological sensors are used to measure meteorological parameters. It is observed that structure constant of refractive index in the surface layer falls with exponent altitude dependence with the power index of -0.8 in the day and -0.3 at night. The contribution of surface layer to the integral turbulence is estimated using coherence length ratio. Coherence length ratio changes in a diurnal cycle with large values in the day and small values during the night and the changing trend and monthly averaged values are different between months. Discussion of relationship between local seeing and meteorological variables shows that local seeing correlates with temperature difference positively in the day while negatively during night. Based on longtime experiments, the results are credible and valuable in the work of site-testing and optimizing the performance of adaptive optical systems..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1101006 (2015)
Atomic and Molecular Physics
Fast and High Probability Production of Single Cesium Atoms in a Magneto-Optical Trap Using Light-Induced Atomic Desorption
Liu Bei, Jin Gang, Wang Jieying, He Jun, and Wang Junmin
Fast and high probability production of single atoms in a cesium (Cs) magneto-optical trap (MOT) is demonstrated by using light-induced atomic desorption(LIAD). The atom’s loading time in a high-gradient vaporcell MOT is reduced by using the violet light emitting diode (LED), which can fire atomic desorption from the iFast and high probability production of single atoms in a cesium (Cs) magneto-optical trap (MOT) is demonstrated by using light-induced atomic desorption(LIAD). The atom’s loading time in a high-gradient vaporcell MOT is reduced by using the violet light emitting diode (LED), which can fire atomic desorption from the inner wall of vacuum glass cell to increase the density of background Cs atoms. The influence of the intensity of the violet LED light to the background atom number is also discussed. Finally, the measured occupation probability of one atom, two atoms, and three atoms are 98.2%, 95.0%, and 80.1% respectively in the MOT. Moreover, this technique could be especially useful for the deterministic loading of a single atom in a single microscopic optical tweezer or in two-dimensional array of microscopic optical tweezer..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1102001 (2015)
Fiber Optics and Optical Communications
Application of Fiber Bragg Gratings in the Measurements of Acoustic Properties of Ice
Markov Alexey, Guo Yao, Chang Tianying, Li Gang, Jia Chengyan, Liu Ye, HongLiang Cui, Gurbanova Natalia, and Talalay Pavel
Based on dynamic strain detection with fiber Bragg gratings，the basic principles of wavelength shift demodulation using matching fiber Bragg gratings are analyzed. The high sensitivity of matching grating demodulation and the advantage of fiber Bragg gratings, which are combined with ultrasonic testing, are innovativelBased on dynamic strain detection with fiber Bragg gratings，the basic principles of wavelength shift demodulation using matching fiber Bragg gratings are analyzed. The high sensitivity of matching grating demodulation and the advantage of fiber Bragg gratings, which are combined with ultrasonic testing, are innovatively used for studying dependence of the propagation of ultrasonic waves on temperature in the ice. By using the fiber Bragg grating, the relationship between the velocity velocities of the longitudinal wave and shear wave, and temperature of the ice samples are detected. Using Matlab for data processing, the relationship of acoustic parameters with temperature in the ice is obtained, which shows that both the longitudinal wave and the shear wave have an increasing trend with the decrease of temperature. The measured data are also compared with ones measured by ultrasonic system, which demonstrates the accuracy and reliability of the data obtained with the fiber Bragg gratings. Therefore, the present technique can be used to conveniently and proficiently study the acoustic properties of ice.海洋公益性行业科研专项经费项目(201405026-01).
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1106001 (2015)
Research of Location System Based on All-Fiber Micro-Vibration Sensor
Han Ping, and Zhu Yangbo
The micro-vibration signal existing as noise is one of the main facts that cause the interference and affect the machining accuracy. The premise of interference elimination is the precise measurement and location of microvibration source. A micro-vibration location system based on full-fiber micro-vibration sensor is pThe micro-vibration signal existing as noise is one of the main facts that cause the interference and affect the machining accuracy. The premise of interference elimination is the precise measurement and location of microvibration source. A micro-vibration location system based on full-fiber micro-vibration sensor is provided, aiming at the shortcoming of existing location system based on fiber. At least 4 micro-vibration sensors are needed in this system, and the position of micro-vibration source is calculated by measuring the time difference of arrival (TDOA) of vibration signal at one sensor relative to other 3 sensors. The performance of sensors and location system is verified by experiment, the relative location error is inferior to 0.56%, and it is stable and reliable..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1106002 (2015)
Research on Signal-to-Noise Ratio Effect in Spatial Scanning Optical Fiber Fabry-Perot Sensing Demodulation System
Jiang Junfeng, Zou Shengliang, Wang Shuang, Liu Tiegen, Liu Kun, and Shi Junfeng
The influence of signal-to-noise ratio (SNR) of spatial low-coherence interference on demodulated interference order jump and absolute phase, combining with monochromatic frequency absolute phase demodulation algorithm，is simulated and analyzed. The simulation result shows that it can avoid interference order jump whenThe influence of signal-to-noise ratio (SNR) of spatial low-coherence interference on demodulated interference order jump and absolute phase, combining with monochromatic frequency absolute phase demodulation algorithm，is simulated and analyzed. The simulation result shows that it can avoid interference order jump when SNR exceeds 18 dB. In this case, standard deviation of demodulated absolute phase decreases linearly with the increase of SNR, and the value of standard deviation with SNR of 25 dB drops to 0.023 rad. The experiment about the influence of SNR on pressure demodulation is investigated through changing optical source intensity, and the experiment result is consisted with the simulation analysis. Pressure demodulation experiment shows that demodulation error decreases with the increase of SNR. Pressure demodulation error is 0.044 kPa when SNR reaches up to 24.79 dB, reduced 2.84 times compared to that with SNR of 18.10 dB. Experiment results indicate that when the pressure is in the range from 5 to 150 kPa, only the value of SNR is greater than 22 dB, and the demodulation accuracy can meet 0.05% F.S.，where F.S. is full scale..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1106003 (2015)
Imaging Systems
Developing of Portable Modulation Transfer Function Tester
Yuan Li, Zhang Xiaohui, Liu Zhenjiang, Han Bing, and Nie Zhenwei
In order to measure modulation transfer function of visible light lenses conveniently and break the monopoly of foreign countries, a small and light and portable modulation transfer function tester is developed. The tester takes pinhole as target. The light from pinhole is collimated by collimator, and then passes throIn order to measure modulation transfer function of visible light lenses conveniently and break the monopoly of foreign countries, a small and light and portable modulation transfer function tester is developed. The tester takes pinhole as target. The light from pinhole is collimated by collimator, and then passes through the lens under test, and forms the pinhole′s image on the image plane of the lens under test. This image is magnified by microscope and received by charge coupled device(CCD) and given to computer. The computer processes the image and calculates the modulation transfer function. The image processing procedure is introduced. The algorithm of modulation transfer function is provided in detail. The influence of components of the test system is analyzed and corrected. The method of restraining error and noise is proposed. This tester′ s results are compared with the theoretical values. It indicates that the absolute accuracy is 0.018, which satisfies the demand of 0.03 and achieves the research purpose..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1111001 (2015)
Illumination Mode Conversion System Design Based on Micromirror Array in Lithography
Xing Shasha, Ran Yinghua, Jiang Haibo, and Xing Tingwen
Source and mask co-optimization is one of the most important resolution enhancement solutions in immersion lithography for nodes 45 nm and below. In order to reconstruct the optimum output pixelated source, a novel illumination mode conversion system design method based on a two-dimensional addressable micro-mirror arrSource and mask co-optimization is one of the most important resolution enhancement solutions in immersion lithography for nodes 45 nm and below. In order to reconstruct the optimum output pixelated source, a novel illumination mode conversion system design method based on a two-dimensional addressable micro-mirror array is proposed. The principle of reducing the number of micro-mirror required to reconstruct the source is analyzed, combing imaging and non-imaging optics, using cylindrical fly-eye lens to achieve the specific nonuniform intensity distribution on micro- mirror array. Based on this, optimization of each title angle of micro-mirror is programmed and the whole system is simulated. The results show the accuracy of the reconstructed source is less than 2.5 %, and pupil non-balance X,Y is below 0.5 %. The simulation results of reconstructed source with Prolith meets the design requirements. Compared with similar systems, the system ensures that the accuracy of reconstructed source with less than 4000 micro- mirror element, it′ s suitable for high integration of the next generation of immersion lithography system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1111002 (2015)
Co-Phasing Error Correction for Segmented Primary Mirror Based on Hybrid Optimization Algorithm
Sun Xue, and Dong Bing
For large aperture space telescope with segmented primary mirror, it is necessary to study in-orbit cophasing error correction method. The image sharpness function is taken as metric function. The relationships between co- phasing errors of segmented mirror and the metric function are analyzed by simulation under monocFor large aperture space telescope with segmented primary mirror, it is necessary to study in-orbit cophasing error correction method. The image sharpness function is taken as metric function. The relationships between co- phasing errors of segmented mirror and the metric function are analyzed by simulation under monochromatic illumination or white- light illumination. Simulation results show that under monochromatic illumination, the dynamic range of piston error correction is less than 0.5 λ. Under white-light illumination, global optimization algorithm should be adopted because of the local maximums of metric function. When piston error is greater than 0.5 λ, stochastic parallel gradient descent (SPGD) algorithm is prone to falling into local maximum and genetic algorithm is capable of finding out the global optimum but with relatively slow iteration speed. A hybrid optimization algorithm based on SPGD algorithm and genetic algorithm is proposed for co-phasing error correction of segmented mirror. When piston error is between - λto λ, the correction accuracy of the hybrid optimization algorithm can be better than 10 nm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1111003 (2015)
Instrumentation, Measurement and Metrology
Study on Visualization of Continuous Deformation Measurement of Thin-Walled Spheres Compressed by Rigid Ball
Dai Meiling, Liu Cong, Dai Yuntong, Wang Liyuan, Zhang Jinlin, Yang Fujun, and He Xiaoyuan
The continuous deformation and crushing behavior of thin-walled spheres compressed by rigid ball is researched experimentally by three dimensional digital image correlation (3D-DIC) technology. In experiment, ping pong balls are selected as thin-walled spheres because of its ideal elastic-plastic material properties anThe continuous deformation and crushing behavior of thin-walled spheres compressed by rigid ball is researched experimentally by three dimensional digital image correlation (3D-DIC) technology. In experiment, ping pong balls are selected as thin-walled spheres because of its ideal elastic-plastic material properties and very thin but uniform wall thickness. Ping pong balls are compressed by a transparent quartz glass ball, which is regarded as a rigid body. It is emphasized that refractive index liquid is introduced to eliminate the image distortion caused by the light refraction of glass ball. 3D-DIC is employed to directly measure the continuous compression deformation of the contact surface of the ping pong balls.The experimental results demonstrate the validity of the proposed method. The plastic ring caused in the compression is measured by 3D-DIC, and the experimental value agrees well with that of theoretical prediction..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1112001 (2015)
Self-Compensating Effect Analysis in Testing Asphere with Computer-Generated Hologram
Gao Songtao, Wu Dongcheng, Peng Shijun, Su Dongqi, and Miao Erlong
Besides null computer-generated hologram (CGH), the alignment CGH is usually designed for aligning the position of CGH through interferogram precisely when testing asphere with CGH. The compensating effect between null CGH and alignment CGH for the CGH which contains null CGH and alignment CGH simultaneously is presentBesides null computer-generated hologram (CGH), the alignment CGH is usually designed for aligning the position of CGH through interferogram precisely when testing asphere with CGH. The compensating effect between null CGH and alignment CGH for the CGH which contains null CGH and alignment CGH simultaneously is presented. Four types of CGHs are designed for a high order asphere, and the compensating effects between the null CGH and alignment CGH are analyzed respectively. The results show that the configuration which has selfcompensating effect suffers less than 1/40 power error, and 1/70 spherical and high order spherical error compared to other configurations. A CGH is fabricated based on the configuration which has self-compensating effect, and thereby, the aspheric fabricating and testing are accomplished iteratively. The final testing results show that the aspheric surface figure converges at 0.48 nm root mean square (RMS)..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1112002 (2015)
Study on Multi-Point Velocity Measurements of Laser Doppler Velocimetry Based on Dual-Core Photonic Crystal Fiber
Huang Xuefeng, Zhao Guanjun, Li Shengji, Guo Feng, Zheng Guanghua, and Xu Jiangrong
To realize multi-point velocity measurements in micro fluid flow, this paper presents a study on laser Doppler velocimetry based on the dual-core photonic crystal fiber. The coherent characteristics and property of measurement volume based on the dual-core photonic crystal fiber are theoretically analyzed. Calculation To realize multi-point velocity measurements in micro fluid flow, this paper presents a study on laser Doppler velocimetry based on the dual-core photonic crystal fiber. The coherent characteristics and property of measurement volume based on the dual-core photonic crystal fiber are theoretically analyzed. Calculation results show that there are five bright interference fringes in measurement volume as the spacing between two fiber cores is about 7.4 μm, which is in agreement with the experiments. Due to the noise in experiment, intensity ratio of each fringe in experiment is lower than that based on the calculation. Enlarging the spacing between two fiber cores results in the increase of interference fringes, thus leads to increase the accuracy of measuring velocity. According to the images during the process from two separated faculae to their interference, the working distance for this velocimetry can be identified as about 30 μm. The principle of multi- point measurements of laser Doppler velocimetry based on the dual-core photonic crystal fiber is analyzed. The test based on the velocimetry is then executed to measure the single point velocity, two-point velocities and three-point velocities. For single point measurement, the averaged velocity of the particle is 0.980 m/s with the relative uncertainty of 0.5%. For two-point measurements, the averaged velocities of the particles are 1.761 m/s and 1.769 m/s, respectively. For three-point measurements, the averaged velocities of the particles are 2.106 m/s, 2.084 m/s and 2.097 m/s, respectively. Experimental results demonstrates that the laser Doppler velocimetry based on the dual-core photonic crystal fiber can realize multi-point velocity measurements. The velocimetry has the advantages with micro sensing head and simple systematic configuration over classical one. Therefore, the velocimetry can be embedded in the micro system for multi-point velocity measurements of micro fluid flow..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1112003 (2015)
Polarization Axis Measurement in Direct Coupling of Y Waveguide Modulator to the Polarization-Maintaining Fiber Coil
Zhen Hongxu, Yang Dewei, Yao Tianlong, and Song Ningfang
A measuring method for the alignment of polarization axis in direct coupling of Y waveguide modulator to the polarization maintaining fiber（PMF）coil is presented. For precisely measuring the polarization axis, an online measurement system including an optical path and an image processing unit is designed and accomplishA measuring method for the alignment of polarization axis in direct coupling of Y waveguide modulator to the polarization maintaining fiber（PMF）coil is presented. For precisely measuring the polarization axis, an online measurement system including an optical path and an image processing unit is designed and accomplished. End-view image of the two paralleled component-Y waveguide and fiber component will be imaged to CCD target surface by inserting the detected path into the direct-coupled process. The process system is used to judge the parallel relationship between the two end edges in the captured image and acquire angle deviation of polarization axis. The waveguide -PMF alignment experimental result shows that the measured data fit the calculated line well. And the measurement error is less than 1°, which means that the polarization crosstalk of the coil pigtail is better than -35 dB caused by the angular error of polarization axis. It is confirmed that the accuracy of the end-view measurement method is feasible for alignment of polarization axis indirect coupling of Y waveguide modulator to the PMF coil..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1112004 (2015)
Pose Measurement System of Double Shield Universal Compact TBM
Yang Wenhui, Lin Jiarui, Gao Yang, and Zhu Jigui
The demand for precision pose measurement of double shield universal compact TBM, a new combinatorial pose measurement system is established. The system combined with monocular vision and laser target, by making use of laser target and total station, pose of back shield is measured real-time, on the basis of that, the The demand for precision pose measurement of double shield universal compact TBM, a new combinatorial pose measurement system is established. The system combined with monocular vision and laser target, by making use of laser target and total station, pose of back shield is measured real-time, on the basis of that, the spatial distribution mode of the optical characteristic points is proposed, by which the characteristic points is recognized, by using the feature points’known geometric constraints and the camera perspective projection model, the intelligent vision sensor can real-time process image, and calculate the position and orientation,the position and orientation between front shield and back shield is measured non- contact.The system builds coordinate transformation relationship between the optical characteristic points, intelligent vision sensor, laser target and total station.The experimental platform which can simulate the position and orientation change of double shield universal compact TBM is established,and the accuracy verification experiment is conducted by a total station, comprehensive pose of TBM is figured out.Experimental results indicate that the precision of the system is less than 5 mm in a field of 30 m×3 m.The measurement system has the advantages of higher precision, real time and rapid speed, as well as strong anti-jamming. It can satisfy precision automatic pose measurement requirements of double shield universal compact TBM in tunnel construction..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1112005 (2015)
Research on a Wavenumber Resolved Low Coherence Interferometry for Step Height Measurement
Zhao Keqiang, Xie Fang, Ma Sen, Wang Yunzhi, and Chen Liang
A high precision step height measurement system, which is based on wavenumber resolved low coherence interferometry, is presented. The information of the measurand is obtained with a fiber Michelson interferometer which is sourced by a broadband light source. The broadband spectrum interferometric beam is dispersed witA high precision step height measurement system, which is based on wavenumber resolved low coherence interferometry, is presented. The information of the measurand is obtained with a fiber Michelson interferometer which is sourced by a broadband light source. The broadband spectrum interferometric beam is dispersed with a bulk dispersing grating to be an optical plate in which the wavelengths are continuously distributed. The optical plate is detected with a linear array charge coupled device (CCD). By transforming the wavelength spectrum of the interferometric signal into wavenumber spectrum, absolute optical path difference of the interferometer can be measured precisely by measuring the wavenumber difference between two neighboring peaks of the wavenumber spectrum. By shorting the length of the interferometric arms in the optical fiber Michelson interferometer, the environmental disturbances are depressed and high measurement precision is obtained. The measurement resolution is as high as 6.03 nm. A step height with the calibrated value of 50 μm that is configurated with two gauge blocks is measured by the system. The standard deviation of 10 times measurement results is 6.8 nm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1112006 (2015)
Investigation of Measurement Uncertainty of Optical Freeform Surface Based on Computer-Generated Hologram
Huang Ya, Ma Jun, Zhu Rihong, Shen Hua, and Gao Zhishan
Optical freeform surface acts an important role in modern optical system. Computer generated hologram which can generate arbitrary wavefronts shows great advantages in the null test of optical freeform surfaces. According to an off-axis aspheric surface, the surface shape deviation can be gotten by testing the initial Optical freeform surface acts an important role in modern optical system. Computer generated hologram which can generate arbitrary wavefronts shows great advantages in the null test of optical freeform surfaces. According to an off-axis aspheric surface, the surface shape deviation can be gotten by testing the initial aspheric surface with Offner compensator. The off-axis aspheric surface lacks of symmetry can be regarded as freeform surface by rotation and translation in the optical path, and a CGH null compensator is designed on flat substrate to achieve null test of the freeform surface. With calculation and analysis of the main errors in the CGH null test, the measurement uncertainty of freeform surface test can reach λ/10[peak- valley(PV) value] level. CGH compensator can be used in the high precision test of freeform surface..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1112007 (2015)
An Optimal Method of Calculating Phase Shift Interference Step Based on Inter-Pixel Algorithm
Wang Xuanze, Yang Liangen, Zhai Zhongsheng, Wu Wenjun, and Xu Zhongbao
For phase-shifting interferometry, the inter-pixel algorithm with ellipse fit is a kind of effective method to get the phase shift steps. The key of improving the precision is to search two groups of pixels, whose phase difference is π/2, from the interferogram. Therefore，The two interferograms with phase difference π/For phase-shifting interferometry, the inter-pixel algorithm with ellipse fit is a kind of effective method to get the phase shift steps. The key of improving the precision is to search two groups of pixels, whose phase difference is π/2, from the interferogram. Therefore，The two interferograms with phase difference π/2 are chosen by calculating the zero and peak positions for local gray mean values of all interferograms. Using these two interferograms, a method is presented to find two groups of pixels of phase difference π/2 with maximum number for the whole image based on four gray comparison methods. The experiment shows that the proposed method has higher accuracy and universality than the traditional method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1112008 (2015)
Integrated Optics
Study of Eliminating Residual Polarization Sensitivity of Array Waveguide Grating with an Embedded Half-Wave Plate
Fu Xu, Mao Jinbin, Xu Ji, Lu Yunqing, and Wang Jin
To eliminate the residual polarization sensitivity of arrayed waveguide grating (AWG) embedded with a half- wave plate, a strategy using optically asymmetrical slab waveguides is proposed. An improved transfer function is given to analyze the polarization mode conversion process with a half-wave plate embedded in AWG. To eliminate the residual polarization sensitivity of arrayed waveguide grating (AWG) embedded with a half- wave plate, a strategy using optically asymmetrical slab waveguides is proposed. An improved transfer function is given to analyze the polarization mode conversion process with a half-wave plate embedded in AWG. For the exemplary case that the half-wave plate is not embedded in the middle of AWG due to fabrication errors, the thermo-optic effect is utilized to adjust the birefringence of the slab waveguides to realize optical asymmetry of them, and the residual polarization sensitivity is eliminated. For the polymer AWG, the simulation results show that when the temperature difference between the input and output slab waveguides is 24 ° C, the residual polarization sensitivity of 32.43 pm can be eliminated. Further the research reveals that the AWG center wavelength drifting can be avoided when the temperature difference of the input and output slab waveguides is equal but with an opposite sign. The proposed method has advantages, such as simple structure and adjustable temperature control, and can also be useful to eliminate the residual polarization sensitivity caused by other factors associated with embedded half-wave plate..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1113001 (2015)
Polarization-Beam Splitter based on Thin-Film Element Hybridly Integrated in Polymer Waveguide
Zhai Yumeng, Wang Jin, Lu Yunqing, Xu Ji, and Fu Xu
Based on the polarization effects and multiple- beam interference effects of optical thin films, a polarization beam splitter (PBS) consisting of multiple TiO2-SiO2 thin film layers is designed, then the hybridintegration scheme within an optical waveguide is proposed and the integration structure is optimized with finBased on the polarization effects and multiple- beam interference effects of optical thin films, a polarization beam splitter (PBS) consisting of multiple TiO2-SiO2 thin film layers is designed, then the hybridintegration scheme within an optical waveguide is proposed and the integration structure is optimized with finite- different time- domain (FDTD) numerical method. The hybrid integration is realized as follows. The multiple TiO2- SiO2 thin film layers are deposited on a substrate made of polymer material, while a slot is fabricated in the polymer waveguide. The thin film element is then inserted in this slot to assemble a compact and hybridly integrated PBS. This hybrid integrated PBS is also characterized experimentally. The results show that, in the C-band (1530 nm to 1565 nm), the device insertion loss is smaller than 2.5 dB, and the polarization splitting ratio is higher than 25 dB. Such a hybridly integrated PBS can be used in present polarization-control optical systems. It also exploits the advantages of the thin film polarization element, thus provides novel schemes and more degrees of freedom, to realize miniaturized and densely integrated PBS..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1113002 (2015)
New Coupler for Exciting Symmetric and Antisymmetric Plasmon Modes in Double-Wire Transmission Lines
Zhang Guohao, and Chen Yuegang
In the subwavelength optical integration, the excitation of surface plasmon polaritons (SPPs) propagation mode in waveguide is important. The structure is designed by using the surface electromagnetic wave holography (SWH) method, and the surface plasmon polariton waves are shaped. The well-designed structures can matcIn the subwavelength optical integration, the excitation of surface plasmon polaritons (SPPs) propagation mode in waveguide is important. The structure is designed by using the surface electromagnetic wave holography (SWH) method, and the surface plasmon polariton waves are shaped. The well-designed structures can match plane surface plasmon polaritons waves to the symmetric and antisymmetric modes in double-wire waveguides. The effective excitation of the two modes in waveguide is realized. The designed structures are validated by the finitedifference time- domain method. The results show that two modes can be excited effectively. The excitation efficiencies of symmetric and antisymmetric modes can reach 8.7% and 10.8%, respectively, after optimizing structure parameters..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1113003 (2015)
Temperature Insensitive Optical Biosensor Based on Polymer Waveguide Microring
Han Xiuyou, Han Xiaonan, Wang Zhiling, Shao Yuchen, Wu Zhenlin, Ren Jun, Wang Jinyan, Teng Jie, and Zhao Mingshan
The temperature sensitivity is the key factor to influence the performance of optical biosensor based on waveguide microring. According the resonant equation of the waveguide microring, the mechanism inducing the temperature sensitivity is analyzed. The sandwich polymer substrate of SU8-NOA61-SU8 is employed to replaceThe temperature sensitivity is the key factor to influence the performance of optical biosensor based on waveguide microring. According the resonant equation of the waveguide microring, the mechanism inducing the temperature sensitivity is analyzed. The sandwich polymer substrate of SU8-NOA61-SU8 is employed to replace the conventional silicon substrate. The thermo- optic effect of the waveguide is counteracted by the thermoexpansion effect of the sandwich polymer substrate, resulting in the temperature insensitivity of the all polymer waveguide microring biosensor. The optimized thicknesses of the sandwich substrate for the temperature insensitive microring sensor are obtained by the design with ANSYS software. The films of SU8 and NOA61 are prepared with the spin coating technique. The controllable thickness precisions of SU8 and NOA61 films are 0.07μm@20r/min and 0.34μm@20r/min, respectively. The temperature sensitivity and the detection limit of the polymer waveguide microring biosensor with the sandwich polymer substrate are as same as the performance of the one on the silicon substrate with a temperature controller..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1113004 (2015)
Lasers and Laser Optics
Hundred-watt Level Spectral Beam Combining Diode Laser Source Based on Mini-Bar Stack
Tan Hao, Meng Huicheng, Yu Junhong, Du Weichuan, Wang Zhao, Guo Linhui, Tian Fei, Lu Fei, Li Jianmin, Gao Songxin, and Wu Deyong
Spectral beam combining is an effective way to realize high brightness direct semiconductor laser output. A hundred watt level spectral beam combining scheme based on mini-bar stack is demonstrated. Due to the lower “smile”effect of mini-bar and equal beam quality in both axis of mini-bar stacks, this mini-bar stack baSpectral beam combining is an effective way to realize high brightness direct semiconductor laser output. A hundred watt level spectral beam combining scheme based on mini-bar stack is demonstrated. Due to the lower “smile”effect of mini-bar and equal beam quality in both axis of mini-bar stacks, this mini-bar stack based spectral beam combining scheme have more effective optical feedback compared to the standard cm-bar based spectral beam combining scheme. A cylindrical mirror as the output mirror to restrain the cross-talk between emitters is utilized instead of using a traditional spatial filter, which will also lower the system size. A spectral beam combining output of 159 W is achieved, with an electro-optical efficiency of 47.35% and spectral width of 11.97 nm. At the operating current of 60A, the beam quality of 3.145 mm · mrad (fast axis) and 3.554 mm · mrad (slow axis) is demonstrated by spectral beam combining..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1114002 (2015)
Materials
Luminescence Properties and Energy Transfer of Ca9NaZn(PO4)7∶CeZ3+, Mn2+ Phosphor
Ma Kun, Ye Jiayi, and Jiang Weizhong
A series of novel single-phase Ca9NaZn(PO4)7∶Ce3+, Mn2+are synthesized by a high temperature solidstate reaction method, and the luminescence properties and energy transfer process are investigated systematically. When excited by 303 nm, the Ce3+ and Mn2+ co-doped phosphor exhibited two emission peaks centered at 374 nA series of novel single-phase Ca9NaZn(PO4)7∶Ce3+, Mn2+are synthesized by a high temperature solidstate reaction method, and the luminescence properties and energy transfer process are investigated systematically. When excited by 303 nm, the Ce3+ and Mn2+ co-doped phosphor exhibited two emission peaks centered at 374 nm and 63 nm, which are ascribed to 5d → 4f and 4T1 (4G) → 6A1 (6S) transition of Ce3+ and Mn2+, respectively. The results show that the existence of efficient energy transfer between Ce3+ and Mn2+ can dramatically enhance the emission intensity of Mn2+, the critical distance is calculated to be 1.385, and this process has been proved to be a resonant type via a dipole-quadrupole interaction. Ultimately, the corresponding CIE coordinates intuitively show the tunable colors from the violet-blue to red area by controlling the relative composition of Ce3+ and Mn2+ content..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1116001 (2015)
Study on Y-shape Power Splitters Based on Broadband and All-Angle Supercollimation Effect of Photonic Crystals
Jia Yajun, Liang Wenyao, and Chen Wuhe
The broadband all-angle super collimation dispersion properties of two-dimensional (2D) elliptical photonic crystal structures with two-fold rotational symmetry and its applications in power splitters are studied. Its dispersion relation is calculated by the plane wave expand method. The calculated results show that thThe broadband all-angle super collimation dispersion properties of two-dimensional (2D) elliptical photonic crystal structures with two-fold rotational symmetry and its applications in power splitters are studied. Its dispersion relation is calculated by the plane wave expand method. The calculated results show that there exist straight-like equi-frequency lines spanning over the whole first Brillouin zone within a relative broad band for TE polarization. These straight-like equi-frequency lines are used to realize broadband all-angle super collimation transmission. Based on the above results, one kind of Y-shape power splitter is designed. Finite-difference Timedomain simulations reveal that this Y-shape splitter has good performance for 2D point source and Gaussian source. The above results have great potential in photonic devices integration and directional coupling..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1116002 (2015)
Analysis of Damage Threshold of MgO-Doped LiNbO3 Crystals
Su Zhuoli, n Meng, Yu Junli, and Zhang Bin
The theoretical model of the interaction between femtosecond lasers and crystal materials is established, in which the effects of electron excitation, carrier absorption and other ionizing process are coupled into the classical double-temperature model. The variations of the electron and lattice temperature with the puThe theoretical model of the interaction between femtosecond lasers and crystal materials is established, in which the effects of electron excitation, carrier absorption and other ionizing process are coupled into the classical double-temperature model. The variations of the electron and lattice temperature with the pulse duration and fluence of femtosecond lasers in MgO∶LiNbO3 crystals with different doping concentration are numerically simulated by the finite-difference method. Furthermore, the variation of damage threshold with the femtosecond pulse width and influence in different doping concentration MgO∶LiNbO3 crystals, as well as the influence of doping concentration on damage threshold are analyzed quantitatively. Results show that, in appropriate doping range, with relatively higher MgO-doped concentration, the carrier mobility of MgO∶LiNbO3 crystals increases, and the damage threshold of the crystals becomes higher. Consequently, the resist damage capability of LiNbO3 crystal may be raised by appropriate MgO doping in practical applications..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1116003 (2015)
Medical Optics and Biotechnology
Handheld Swept Source Optical Coherence Tomography for Imaging Human Skin in vivo
Shi Weisong, Gao Wanrong, and Chen Chaoliang
A handheld swept source optical coherence tomography (SSOCT) system is described for imaging human skin in vivo. The performance of the system is analyzed in detail, and compared to the spectral domain optical coherence tomography (SDOCT) system in our laboratory. The results show that the sensitivity of the handheld SA handheld swept source optical coherence tomography (SSOCT) system is described for imaging human skin in vivo. The performance of the system is analyzed in detail, and compared to the spectral domain optical coherence tomography (SDOCT) system in our laboratory. The results show that the sensitivity of the handheld SSOCT system and the traditional SDOCT system is 101 dB and 94 dB, respectively. A phantom experiment and two in vivo experiments on different human skin areas are carried out to demonstrate the better performance of the handheld SSOCT system in terms of signal to noise ratio (SNR) and the maximum imaging depth. The inner side of a human arm is imaged successfully with the handheld SSOCT system, which suggests that the handheld SSOCT system can image any position of human skin. All the results indicate that the handheld SSOCT system can not only be used to image skin anywhere conveniently, but also offer the structure images with high quality..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1117001 (2015)
High-Speed Compact Adaptive Optics Scanning Laser Ophthalmoscope
Jiang Huilü, Liao Na, Li Chaohong, Li Yiyu, Chen Hao, Huang Jinhai, and Wang Qinmei
Confocal scanning laser ophthalmoscopy based on adaptive optics (AO) aberration correction technology is the recent research focus, and provides powerful support in early diagnosis of ocular fundus diseases. A highspeed compact adaptive optics scanning laser ophthalmoscope (AOSLO) is built by employing deformable mirroConfocal scanning laser ophthalmoscopy based on adaptive optics (AO) aberration correction technology is the recent research focus, and provides powerful support in early diagnosis of ocular fundus diseases. A highspeed compact adaptive optics scanning laser ophthalmoscope (AOSLO) is built by employing deformable mirrors and Shack- Hartmann wavefront sensors, with 350 mm × 400 mm system size and 40 fps frame rate of image collection. The system resolution measurement and human retinal imaging experiments are carried out respectively, and the results indicate that the real resolution in human retina of this system is 2.50 μm, close to the diffraction limit resolution which is 2.32 μm, and the system can be used to image the retina at cell level. Meanwhile, the experimental results show that the adaptive optics system can correct aberration of human eyes, image quality is significantly improved after AO, and the retinal blood vessels near optic disc and retina cones in fovea region for human eyes are observed clearly..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1117002 (2015)
Parallelization of 3D Thinning Algorithm for Extracting Skeleton of Micro-CT Vasculature
Tan Hai, Wang Dadong, Xue Yanling, Wang Yudan, Yang Yiming, and Xiao Tiqiao
The extraction of skeleton is often a crucial step in quantitative assessment of three-dimensional (3D) vasculature computed tomography (CT) image. The process always consumes several hours to get the skeleton, which confines the efficiency of quantitative analysis. By means of OpenMP, a parallel designing method basedThe extraction of skeleton is often a crucial step in quantitative assessment of three-dimensional (3D) vasculature computed tomography (CT) image. The process always consumes several hours to get the skeleton, which confines the efficiency of quantitative analysis. By means of OpenMP, a parallel designing method based on sequential thinning is proposed to improve the computational time of the skeletonization. The implemented method is utilized for different sizes of real 3D vascular CT images in order to evaluate its performance and efficiency. The testing results show that the proposed method, which is implemented in 16-thread parallel, does not only extract precise skeleton, but also conspicuously reduces the processing time to an acceptable scale. The corresponding computational time is reduced from 176 min to 13 min. Therefore, the time efficiency of quantitative assessment is no longer an obstruction for the analysis of the large scale 3D vasculature CT images..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1117003 (2015)
Optical Design and Fabrication
Hybrid Compensation Testing of Convex Asphere with Computer Generated Holograms and Fold Sphere
Li Ming, Yan Lisong, Xue Donglin, Zhao Jingli, Zheng Ligong, and Zhang Xuejun
Large convex aspheric mirrors are widely used in optical system, especially for off-axis three mirror systems as secondary mirrors. Considering the mechanical and thermal properties, SiC is chosen as the material of the mirror, which is opaque. For off-axis optical system, the full aperture of the secondary mirror is uLarge convex aspheric mirrors are widely used in optical system, especially for off-axis three mirror systems as secondary mirrors. Considering the mechanical and thermal properties, SiC is chosen as the material of the mirror, which is opaque. For off-axis optical system, the full aperture of the secondary mirror is used for imaging. Because of the properties of large convex aphereric mirrors, such as large aperture, opacification and no obstruction in the optical system, testing of this kind of asphric mirrors can′t be accomplished with traditional method. To solve the testing problem, hybrid compensation testing method with computer-generated hologram (CGH) and fold sphere is proposed, and an alignment method based on the assistant areas of CGH is proposed too. With actual project, a φ120 mm mirror is tested using hybrid compensation testing method. The testing result is the same with the stitching testing result at 1/50 λ root mean square (RMS), which proves the feasibility and validity of the hybrid compensation testing method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1122001 (2015)
Design and Analysis of the Expansion Compound Eye Used in Micro-Miniature Static Fourier Transform Infrared Spectrometer
Chen Cheng, Liang Jingqiu, Liang Zhongzhu, ü Jinguang, Qin Yuxin, Tian Chao, and Wang Weibiao
In a stepped-mirror-based static Fourier transform infrared spectrometer, the expansion lenses based on classical lenses has several lenses, large aperture and overall length, and its volume and mass have major proportion comparing to the whole system. That limits the development of micro- miniature and lightweight speIn a stepped-mirror-based static Fourier transform infrared spectrometer, the expansion lenses based on classical lenses has several lenses, large aperture and overall length, and its volume and mass have major proportion comparing to the whole system. That limits the development of micro- miniature and lightweight spectrometer seriously. However, compound eye is helpful to solve the problem because it has these advantages including of compact structure, smaller volume and lighter weight. In this paper, the structure parameters of compound eye consist of three microlens arrays are analyzed by the method of matrix formalism and optimized by optics design software, and the stop array for weaken the stray light is designed. Finally, the interferogram and the recovered spectrum of the spectrometer are obtained by the ray tracing software, and the result shows that the designed expansion compound eye can meet the application requirement of the spectrometer..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1122002 (2015)
Optical Devices
Study on Refractive Index Sensing Property of Air Gate Photonic Crystal F-P Cavity Based on Evanescent Wave Resonance
Chen Ying, Shi Jia, Cao Huiying, Han Yangyang, Zhu Qiguang, and Bi Weihong
Based on the theory of evanescent wave and optical resonance, the existence form of evanescent wave in photonic crystal and the refractive index sensing mechanism of air gate photonic crystal F-P cavity are studied, and the relationship model between the resonant wavelength and the detected gas refractive index is estaBased on the theory of evanescent wave and optical resonance, the existence form of evanescent wave in photonic crystal and the refractive index sensing mechanism of air gate photonic crystal F-P cavity are studied, and the relationship model between the resonant wavelength and the detected gas refractive index is established. When the incident light travels through the photonic crystal at a certain angle, which is larger than the critical angle of total reflection, as a result of the action of evanescent wave, an F-P cavity is formed in the center of dielectric layer and produces resonance. The electromagnetic field is local enhanced, and contacts with detected gas sufficiently, which causes the refractive index sensing structure has a high sensitivity with the detected gas refractive index. The transfer matrix theory is used to numerical simulation, the results show that the Q value can attain 3447.0 and the sensitivity can attain 1260.0 nm/RIU. So the proposed photonic crystal F-P cavity refractive index sensing structure has good sensing properties, and provides certain theoretical references for the design and application of high precision gas refractive index sensors..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1123001 (2015)
Propagation Properties of Nano Dielectric Parallel Lines Coated with Graphene
Zhai Li, Xue Wenrui, Yang Rongcao, and Han Liping
A kind of surface plasmonic waveguide constructed with double elliptical nano dielectric parallel linescoated with graphene is proposed. The dependence of propagation properties on electromagnetic parameters and structure parameters is studied by using the finite element method.The results show that, when the distance A kind of surface plasmonic waveguide constructed with double elliptical nano dielectric parallel linescoated with graphene is proposed. The dependence of propagation properties on electromagnetic parameters and structure parameters is studied by using the finite element method.The results show that, when the distance between two ellipses is increased, the real part of the effective refractive index is decreased gradually, and the propagation distance is increased first and then is fallen down, and the mode area is increased gradually. The effective refractive index, the propagation length and the mode area can be adjusted finely by the elliptical semi minor axis. It can achieve better transmission effect by reducing the distance between parallel lines and increasing the length of the semi minor axis of the parallel lines through the optimization calculation. The higher the working frequency is, the smaller the real part of the effective refractive index is, the shorter the propagation distance is, and the larger the mode area is. The higher the temperature is, the larger the real part of the effective refractive index is, the shorter the propagation distance is, and the smaller the mode area is. This work provides a theoretical basis for the design, fabrication and application of the surface plasmon waveguide based on graphene material..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1123002 (2015)
Lens Array with Double Freeform Surface for LED Backlight in LCD Imaging Engine of Helmet-Mounted Display
Feng Qibin, Li Yani, Li Qigong, and Lü Guoqiang
Light emitting diode (LED) has become a mainstream backlight technology for liquid crystal display (LCD) imaging engine of helmet-mounted display.With large emitting angle, a lot of lights from LED can’t be used effectively, causing power waste. The backlight consists of LED array. The secondary optical design can helpLight emitting diode (LED) has become a mainstream backlight technology for liquid crystal display (LCD) imaging engine of helmet-mounted display.With large emitting angle, a lot of lights from LED can’t be used effectively, causing power waste. The backlight consists of LED array. The secondary optical design can help to improve the luminous efficiency. A double-freeform-surface lens is proposed, which forms a circle spot with a 8mm diameter. The lens is cut to form a rectangle spot. However, the hot spot appears, caused by the total reflection. The lens is then optimized, forming a rectangle spot with high uniformity. 4 lens are combined to become a lens array. In order to eliminate stray lights, the optimization on lens is performed again. The prototype of lens array is developed and the backlight unit with lens array is measured. The measurement results show that compared with the common backlight, the luminance of the backlight with 2 diffusers and lens array increases by 96.4%, the nonuniformity of 23.1% is slightly improved from 23.8%，the viewing angle of half-luminance decreases from 39° to 23°. The designed lens array satisfied the requirements of the LED backlight in LCD imaging engine of helmet-mounted display..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1123003 (2015)
Optimization for Raman Fiber Amplifiers Based on Least Squares Support Vector Regression Model
Chen Jing, Jiang Hao, Liu Tundong, and Qiao Sun
Solving the coupled Raman amplification is the main limitation to the efficiency of the existing optimization method for Raman fiber amplifier design. The least squares support vector regression model is applied to address this issue. Instead of directly calculating the Raman coupled equation, a multi-input multi-outpuSolving the coupled Raman amplification is the main limitation to the efficiency of the existing optimization method for Raman fiber amplifier design. The least squares support vector regression model is applied to address this issue. Instead of directly calculating the Raman coupled equation, a multi-input multi-output model for Raman fiber amplifier is established. A C-band Raman fiber amplifier with a gain ripple level of ± 0.5 dB is designed using only two pumps. Additionally, the on-off gain can be quickly and directly adjusted by the proposed model. Compared with the shooting algorithm and average power analysis technique, the results indicate that the proposed regression model greatly improves the solving efficiency..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1123004 (2015)
Reviews
Coupling Analysis Between Symmetrical Circular Areas in ZnO Random Laser
Li Zhiquan, Zhao Jingjing, Meng Xiaoyun, Piao Ruiqi, Li Wenchao, Niu Liyong, and Gu Erdan
The coupling characteristics of light- wave between two symmetrical circular areas in the twodimensional ZnO random scattering particles are studied. The distribution of the optical filed and the spectrogram of mode in two-dimensional random scattering particles system are numerically simulated and compared by using thThe coupling characteristics of light- wave between two symmetrical circular areas in the twodimensional ZnO random scattering particles are studied. The distribution of the optical filed and the spectrogram of mode in two-dimensional random scattering particles system are numerically simulated and compared by using the finite difference time domain (FDTD) method, when the distance D between the two symmetrical circular areas changes. The dependence of the emission intensity and the center wavelength on D is analyzed and it is obtained that the wavelength with 380.57 nm and the intensity of laser with 4.81 × 104 are the optimal parameters while D = 0.8 μm. In ideal conditions, the optical field distribution of scattering system is observed during the simulation process. The result shows that the electric field intensity between two circular areas is amplified after coupling. With the increasing of D which is the distance between the circular regions, the electric field intensity is enhanced, the spectral line width is decreased, and the number of modes is reduced..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1114001 (2015)
Spectroscopy
Study on Interferogram-Spectrum Modulation by the Rotation of Compensation Plate in Static Fourier Transform Spectrometer
Lü Jinguang, Liang Jingqiu, Liang Zhongzhu, Qin Yuxin, and Tian Chao
Due to the restriction of systemica lignment precision in static Fourier transform spectrometer, the compensation plate may produce a definite rotation angle relative to beam splitter.The rotation of the compensation plate makes the interferogram dislocation and the optical path difference change, and then induces the Due to the restriction of systemica lignment precision in static Fourier transform spectrometer, the compensation plate may produce a definite rotation angle relative to beam splitter.The rotation of the compensation plate makes the interferogram dislocation and the optical path difference change, and then induces the interferogram image distortion. By means of the calculation to the propagation path of beam in compensation plate, the relationship between interferogram dislocation and optical path difference change and rotation angle of compensation plate is gained, and according to which, the aliasing of interferogram images from various wavelengths aliasing and the spectrum distortion are simulated and analyzed. Toward the phase error introduced by rotation of compensation plate, arithmetic of resolving the linear equation by discrete spectrum sequence is brought forward, the result indicates that the error spectrum can be corrected effectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1130001 (2015)
Temperature Measurement of Flame at Converter Mouth Based on Multi-Spectral Thermometry
Shao Yanming, Zhao Shu′an, Chen Yanru, Yu Renlong, and Zhao Qi
The non- contact online temperature measurement of the flame at the converter mouth during the basic oxygen steelmaking process is investigated. Multi- spectral radiation thermometry based on the least squares method in which no emissivity model is needed is adopted for the flame temperature measurement. A flame radiatThe non- contact online temperature measurement of the flame at the converter mouth during the basic oxygen steelmaking process is investigated. Multi- spectral radiation thermometry based on the least squares method in which no emissivity model is needed is adopted for the flame temperature measurement. A flame radiation signal collection system at the converter mouth is constructed by taking the Ocean Optics miniature spectrometer USB4000 as the beam split element. The responsivity of the proposed system is obtained by adopting the radiation of the liquid steel in the converter whose temperature is close to that of the flame at the converter mouth for the system calibration. Temperature of the liquid steel during tapping is measured using spectral data of different wavelength bands with responsivity obtained by the improved calibration method and the halogen lamp method, respectively. The results show that the improved calibration method can achieve the best performance in the wavelength band of 600~740 nm. The online flame temperature measurement at the converter mouth is carried out with the proposed method, and the variation in the flame temperature during the steelmaking process is obtained. The results show that the proposed method can not only indicate the impact of the converter operation on the flame temperature at the converter mouth, but also offer a useful auxiliary way for the operators to control the temperature of the liquid steel in the converter..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1130002 (2015)
X-Ray Optics
Designment of a Femtosecond Streak Camera with a Novel Accelerating Structure
Gu Li, Zong Fangke, Li Xiang, hang Jingjin, Zhang Chi, and Yang Qinlao
To improve the performance of the femtosecond streak camera, a novel accelerating structure is designed and applied to streak camera with accelerating mesh and slit channel, parallel plate electrodes. Considering X-ray incident on CsI photocathode in actual inertial confinement fusion(ICF) experiment, large photoelectrTo improve the performance of the femtosecond streak camera, a novel accelerating structure is designed and applied to streak camera with accelerating mesh and slit channel, parallel plate electrodes. Considering X-ray incident on CsI photocathode in actual inertial confinement fusion(ICF) experiment, large photoelectron energy dispersion and the space charge effect, 2000 photoelectrons’energy and angular are sampled with Monte Carlo simulation, their trajectories are calculated with the fourth-order Runge Kutta method. Time and space resolution of streak camera with this novel accelerating structure are obtained by analyzing electron time and space distribution on the imaging surface, and the result shows that time resolution is up to 508.4fs and space resolution is up to 21l lp/mm. Compared to the traditional parallel plate electrode streak camera, the time and space resolution are significantly improved by 90% and 29% respectively. The novel accelerating structure of the streak camera is simple and practical..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1134001 (2015)
Measurement of Line Absorption Coefficient of Cylindrical Tungsten/Glass Complex Optical Component
Wang Xuepeng, Yang Jing, Wang Lili, Li Yude, Guo Fei, Zhao Weilin, Fu Site, and Lin Xiaoyan
A cylindrical tungsten/glass complex optical component is proposed for the transmission of high energy X-ray. The cylindrical tungsten/glass complex optical component uses tungsten film to reflect and focus high energy X-ray. Using a Matlab program, the line absorption coefficients of metal Cu and the tungsten/glass coA cylindrical tungsten/glass complex optical component is proposed for the transmission of high energy X-ray. The cylindrical tungsten/glass complex optical component uses tungsten film to reflect and focus high energy X-ray. Using a Matlab program, the line absorption coefficients of metal Cu and the tungsten/glass complex optical component are calculated. Theoretical calculation results of metal Cu agree with common databases and the saltation of the line absorption coefficient at the absorption edge proves the high- precision of this program. Calculation results of the optical componentare consistent with experimental results, which prove the optics can filter low-energy X-ray..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 11, 1134002 (2015)
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