Contents
2011
Volume: 31 Issue 2
49 Article(s)
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Atmospheric Optics and Oceanic Optics
A Denoising Method for Backscatter Signal of Laser Ceilometer Based on Hilbert-Huang Transform
He Junfeng, Liu Wenqing, Zhang Yujun, Chen Zhenyi, Ruan Jun, and Wang Liming
A denoising method combined with Hilbert-Huang transform (HHT) time-frequency analysis for backscatter signal of laser diode ceilometer based on HHT and Savitzky-Golay filtering is proposed. Considering characteristics of ceilometer backscatter signal proper structure of adaptive time-variant time-space filtering bank A denoising method combined with Hilbert-Huang transform (HHT) time-frequency analysis for backscatter signal of laser diode ceilometer based on HHT and Savitzky-Golay filtering is proposed. Considering characteristics of ceilometer backscatter signal proper structure of adaptive time-variant time-space filtering bank (TFB) assisted by Savitzky-Golay filtering is selected to suppress noise. Then, HHT time-frequency analysis is used to observe signal features and test denoising effect. It is proved by plenty of test data under various weather conditions that the method can help to suppress noise without deteriorating signal features and improve the ability of cloud base and height identification, and finally obtain precise retrieving of vertical visibility..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 201001 (2011)
Atmospheric Turbulence Random Phase Difference with the Demodulating Algorithm of Correlation
Xiao Shumei, Mei Haiping, Qian Xianmei, and Rao Ruizhong
An algorithm for real-time demodulation of random turbulence phase difference is proposed according to the principle and signal expression of fiber optic turbulence measurement system. Fixed, waveform and random turbulence phase difference are all simulated and demodulated to demonstrate the applicability of the algoriAn algorithm for real-time demodulation of random turbulence phase difference is proposed according to the principle and signal expression of fiber optic turbulence measurement system. Fixed, waveform and random turbulence phase difference are all simulated and demodulated to demonstrate the applicability of the algorithm. Result shows that absolute error between demodulated and simulated phase difference is less than 10-3, which satisfies the demand of turbulence measurement. The research provides an important theoretical method to detect the dynamic phase difference of optical turbulence..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 201002 (2011)
Atomic and Molecular Physics
Electrostatic Trapping of Cold Polar Molecules on a Chip
Ma Hui, Xu Xueyan, and Yin Jianping
A novel scheme is proposed to realize the electrostatic surface trapping of cold polar molecules on a chip by using a square charged wire. The spatial distribution of the electrostatic field around the square charged wire is calculated. Then the dependent relation between the position of trapping center and the geometrA novel scheme is proposed to realize the electrostatic surface trapping of cold polar molecules on a chip by using a square charged wire. The spatial distribution of the electrostatic field around the square charged wire is calculated. Then the dependent relation between the position of trapping center and the geometric parameters is analyzed. Afterwards, the dependences of the electric field distribution (including the corresponding Stark trapping potential for CO molecules) on the geometric parameters of the square wire is studied in the x and z direction. The study shows that the efficient trapping potential for CO molecules is greater than 130 mK, which is high enough to trap cold polar molecules with a temperature of 50 mK in the weak-field-seeking states. Obviously, the electrostatic surface trapping proposed here has some important applications in the fields of molecular optics and molecular chip, quantum optics, quantum computing and quantum information processing, etc..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 202001 (2011)
Diffraction and Gratings
Optimization of Double-Grating Flat-Field Holographic Concave Grating Spectrograph
Kong Peng, Bayanheshig, Li Wenhao, Tang Yuguo, and Cui Jinjiang
The optimization method for the double-grating flat-field spectrographs which employ two aberration-corrected holographic concave gratings is described. The spectral range of the spectrograph is divided into two parts which are covered by two gratings respectively. The two gratings have the same using geometry and are The optimization method for the double-grating flat-field spectrographs which employ two aberration-corrected holographic concave gratings is described. The spectral range of the spectrograph is divided into two parts which are covered by two gratings respectively. The two gratings have the same using geometry and are fabricated with different recording geometries for the correction of aberrations, such as defocus, coma, astigmatism and spherical aberrations. A double-grating flat-field spectrograph with a wavelength range of 200~800 nm and detector length of 25 mm is designed. The spectral resolution performance is compared with a single-grating flat-field spectrograph which is designed following the same specifications. The results indicate that the spectral resolution performance can be greatly improved when the double-grating spectrograph is used..
Acta Optica Sinica
- Publication Date: Aug. 13, 2021
- Vol. 31, Issue 2, 205001 (2011)
Fiber Optics and Optical Communications
Dual-Wavelength Pumped Supercontinuum Generation in Tapered Photonic Crystal Fibers
Xi Xiaoming, Chen Zilun, Sun Guilin, Chen Hongwei, Li Zhihong, Huang Zhihe, and Hou Jing
By using 1064 nm pulsed laser the front section (77 cm) of photonic crystal fiber (PCF) is pumped and 747 nm signal light is got by four-wave mixing. The end part of the PCF is tapered and has two zero-dispersion wavelengths (ZDW). The 747 nm signal light and 1064 nm pulsed laser which locate in the anomalous dispersioBy using 1064 nm pulsed laser the front section (77 cm) of photonic crystal fiber (PCF) is pumped and 747 nm signal light is got by four-wave mixing. The end part of the PCF is tapered and has two zero-dispersion wavelengths (ZDW). The 747 nm signal light and 1064 nm pulsed laser which locate in the anomalous dispersion regime between two zero-dispersion wavelengths are pumped into the tapered PCF. Supercontinuum with more than spectral width of 600~1700 nm (at 20 dB level) is generated in the tapered PCF which has 25 μm outer diameter and 27 cm length..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 206001 (2011)
Non-Return-to-Zero to Return-to-Zero Format Converter for Quaternary Amplitude Shift Keying Signal Based on Cascaded Modulators
Yu Wenke, Lou Caiyun, Zhao Xiaofan, Lu Dan, and Chen Jianhua
A novel non-return-to-zero (NRZ) to return-to-zero (RZ) format converter for quaternary amplitude shift keying (4-ASK) signal is proposed based on phase-intensity modulators and one dispersion compensating fiber (DCF) module. The operation principle of the proposed converter is described theoretically. 20-Gb/s NRZ-4-ASA novel non-return-to-zero (NRZ) to return-to-zero (RZ) format converter for quaternary amplitude shift keying (4-ASK) signal is proposed based on phase-intensity modulators and one dispersion compensating fiber (DCF) module. The operation principle of the proposed converter is described theoretically. 20-Gb/s NRZ-4-ASK signal to RZ-4-ASK signal conversion is also experimentally demonstrated. The results show that 20-Gb/s NRZ-4-ASK signal could be successfully converted to RZ-4-ASK signal without wavelength shift and the pulse width of the converted signal is narrow. The timing-jitter of the converted signal is lower than the original one. The format converter could also be applied to multi-wavelength amplitude shift keying conversion..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 206002 (2011)
Microstructured-Fiber Surface Plasmon Resonance Sensor
Guan Chunying, Yuan Libo, and Shi Jinhui
A microstructured-fiber containing six large air holes is proposed to achieve surface plasmon resonance (SPR) sensor. The finite element method is used to analyze characteristics of the SPR sensor. The effects of the thickness of metal films, pitch between air holes, diameter of air holes and refractive index of liquidA microstructured-fiber containing six large air holes is proposed to achieve surface plasmon resonance (SPR) sensor. The finite element method is used to analyze characteristics of the SPR sensor. The effects of the thickness of metal films, pitch between air holes, diameter of air holes and refractive index of liquid on the resonance wavelength are elucidated. The sensitivity of sensor is also given. The result shows that the resonance wavelength is sensitive to the thickness of metal film and refractive index of environment, while the resonance wavelength does not change basically when the pitch between air holes and diameter of air holes varies. The proposed SPR sensor exhibits high sensitivity up to 10-4..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 206003 (2011)
Fourier Optics and Signal Processing
Fiber-Optic Interferometer Projection of Real-Time Fourier Profilometry
Zhang Chao, Duan Fajie, Xing Minghao, and Hu Bo
Fringe using optical fiber which is from Young′s double hole interference theory and by formation of Mach-Zender interferometer are projected. At the same time, the deformed fringe images is taken by a high speed CMOS camera. By means of computer vision, automated high-speed fringe image processing with the help of opeFringe using optical fiber which is from Young′s double hole interference theory and by formation of Mach-Zender interferometer are projected. At the same time, the deformed fringe images is taken by a high speed CMOS camera. By means of computer vision, automated high-speed fringe image processing with the help of open source computer vision (OpenCV) is achieved. Rotating rectangular algorithm is proposed to the automated selection of Fourier filtering window. A variety of phase-unwrapping algorithm is discussed. The overall time complexity of the algorithm for the measurement is O(nlg n) and the measurement time is less than 200 ms. By visual calibration, RMS error is 0.2 mm..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 207001 (2011)
Fourier Computer-Generated Hologram Digital Watermarking with Nonlinear Amplitude Limiting
Chen Daqing, Zhou Hao, Tao Zhi, and Gu Jihua
A new approach of Fourier computer-generated hologram (CGH) digital watermarking with nonlinear amplitude limiting is proposed，which realizes better robustness. The amplitude and phase are extracted on the basis of traditional Fourier transform holography. Binary Fourier hologram is formed by nonlinear amplitude limitiA new approach of Fourier computer-generated hologram (CGH) digital watermarking with nonlinear amplitude limiting is proposed，which realizes better robustness. The amplitude and phase are extracted on the basis of traditional Fourier transform holography. Binary Fourier hologram is formed by nonlinear amplitude limiting algorithm when the phase information as input function and the amplitude information transferred into a bias function, because the binary hologram has stronger anti-interference property than the normal hologram, and the digital watermarking of much better robustness can be obtained. To improve the watermark′s resistance to compression, hologram is embedded in the frequency domain through discrete cosine transform. Theoretical analysis and numerical experiments show that the algorithm has more robustness to image lossy compression, cropping and filter, compared with the algorithm based on traditional Fourier CGH watermarking..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 207002 (2011)
Instrumentation, Measurement and Metrology
High-Temperature Digital Image Correlation Method Based on Optical Band-Pass Filtering Imaging
Pan Bing, and Wu Dafang
Digital image correlation (DIC) technique based on band-pass filtering imaging for full-field deformation measurement of high-temperature objects is proposed. The DIC technique employs a narrow band-pass optical filter to alleviate the influence of thermal radiation of high-temperature sample on the captured images. AsDigital image correlation (DIC) technique based on band-pass filtering imaging for full-field deformation measurement of high-temperature objects is proposed. The DIC technique employs a narrow band-pass optical filter to alleviate the influence of thermal radiation of high-temperature sample on the captured images. As a result of this approach, high-quality digital image of the test sample surface at 1000 ℃ can be acquired and can be directly processed by DIC to extract full-field deformation. The full-field thermal deformation and coefficient of thermal expansion of a chromiumnickel austenite stainless steel sample at the temperature range of 16.5 ℃~1000 ℃ are measured to verify the proposed technique. Experimental results clearly indicate that the proposed technique can achieve high-accuracy measurements with simple principle and implementation, and is expected to find more engineering applications..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 212001 (2011)
Study of the Error of the Reference Lens in Absolute Spherical Testing and the Thermal Deformation Model Establishment
Chen Xu, Yuan Wenquan, Feng Yutao, Wang Ping, and Liu Weiqi
Absolute measurement is an important method to improve the accuracy of the Fizeau interferometer. To achieve the high accuracy of the reference wave front in absolute spherical testing, the influence of environmental factors including temperature, gravity and clamping force was studied. The Gram-Schmidt fitting was useAbsolute measurement is an important method to improve the accuracy of the Fizeau interferometer. To achieve the high accuracy of the reference wave front in absolute spherical testing, the influence of environmental factors including temperature, gravity and clamping force was studied. The Gram-Schmidt fitting was used to fit the deformation of the reference surface in representation of the Zernike coefficients. The contribution of the thermal deformation by temperature change and the change in Zernike coefficients caused just by temperature change were compared. The model of the thermal deformation was created and the corresponding aberration mode of the reference surface was analyzed which make the separation of the deformation caused by temperature possible so that the test accuracy can be enhanced. The result indicates that the deformation of fused silica is smaller than that of K9 and zerodur on the whole while the deformation of zerodur is smaller than that of K9 and fused silica in just temperature change. When the temperature takes one degree change, the root mean square of the zerodur surface reaches 0.37 nm..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 212002 (2011)
Correction of Observation Angle in Solar Radiation Monitor
Zhang Jiaqi, Qi Jin, Fang Wei, Qiu Hong, and Lu Jingbin
During the sun′s sweep of the field of view of solar radiation monitor, varying function of incident angle and temperature response of radiometer receiver cavity is studied. Calibration of time-varying incident angle for solar radiation monitor is also discussed. The absolute radiometer of solar radiation monitor detecDuring the sun′s sweep of the field of view of solar radiation monitor, varying function of incident angle and temperature response of radiometer receiver cavity is studied. Calibration of time-varying incident angle for solar radiation monitor is also discussed. The absolute radiometer of solar radiation monitor detects small changes of the radiation through electrical calibration. We take radiation power of these small changes as a factor to revise solar radiation. FY-3 satellite has measured more than 2×104 sets of data in the past two years. The data is amended through the changes of observation angle and the obtained value of solar constant is 1368±4 W/m2, and the uncertainty is 0.3%. This result is in areement well with the value of 1367±7 W/m2 which is recommended by World Meteorological Organization and data measured on other satellites in the same period..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 212003 (2011)
Experimental Study of Segmented Mirrors Co-Phase Using Dispersed Fringe Sensor
Zhang Yong, Zhang Liang, Liu Genrong, Wang Yuefei, Zhang Yajun, Zeng Yizhong, and Li Yeping
For segmented primary mirror of extremely large telescope, in order to make the image quality of telescope system reach the diffraction limit, sub-mirrors positioning accuracy requires to meet the requirements of co-phase. So the piston errors between sub-mirrors need accurate measurements and corrections in real time.For segmented primary mirror of extremely large telescope, in order to make the image quality of telescope system reach the diffraction limit, sub-mirrors positioning accuracy requires to meet the requirements of co-phase. So the piston errors between sub-mirrors need accurate measurements and corrections in real time. On the basis of analyzing dispersed fringe sensing (DFS) and disperse Hartmann sensing (DHS) principles, a dispersed fringe sensor was built and some detection experiments on an indoor segmented mirror active optics experimental system were carried out. A certain relation is confirmed between the sensing result and relative piston error value of sub-mirrors. So piston errors can be detected indirectly. And experimental results were analyzed for error factors, which affect the measurement accuracy greatly. They are fringe visibility, spectral curve calibration, nonlinear least squares and so on. During the real test experiments, solutions are also proposed to improve the data processing. The results indicate that the present measurement accuracy is up to 20 nm in the range of ±15 μm..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 212004 (2011)
Fabrication of the Muti-Mode Rib-Waveguide and Its Coupling and Wasting Measurement System
Wen Changli, Ji Jiarong, Feng Xianghua, Song Yansheng, and Dou Wenhua
Nowadays, an important device called vertical cavity surface emitting laser is applied into optical interconnection more and more widely, it works at 850 nm and its output cross section is 50 μm×50 μm. In order to fit to this device, a muti-mode rib waveguide with a big cross section is needed. And the distance amNowadays, an important device called vertical cavity surface emitting laser is applied into optical interconnection more and more widely, it works at 850 nm and its output cross section is 50 μm×50 μm. In order to fit to this device, a muti-mode rib waveguide with a big cross section is needed. And the distance among chips needs longer the waveguide. A waveguide which is 21 cm long with a big section is fabricated through advancing the making technology and light can go through it successfully. A measurement system is also designed and the average wasting of the waveguide as 0.18 dB/cm is gotten which is verified through cutting-off method. Also, this system can be applied to adjusting the coupling of the waveguide input with invisible light..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 212005 (2011)
Integrated Optics
Research on Divergence-Angle Suppression Techniques in the Collimator System of Angle-Tuned Filter
Yu Kan, Bao Jiaqi, Huang Dexiu, Yin Juanjuan, and Chang Jin
The divergence angle of an incident beam will change the characteristics of a narrow-band angle-tuned thin-film filter whose passband will decrease and divergence loss will increase. This phenomena will be more and more obvious while the incident angle is increasing. Here its reason is analyzed. According to the LagranThe divergence angle of an incident beam will change the characteristics of a narrow-band angle-tuned thin-film filter whose passband will decrease and divergence loss will increase. This phenomena will be more and more obvious while the incident angle is increasing. Here its reason is analyzed. According to the Lagrange-Helmholtz principle, a beam expander is designed to compress the divergence angle of the incident beam. The double filtering technology is used to enhance the passband stability and the rectangle factor of the angle-tuned filter. One kind of shaping optic system is fabricated to the 100 GHz DWDM narrow-band angle-tuned filter. Experimental results show that the shaping system could effectively eliminate the influence of the divergence angle to the filter..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 213001 (2011)
Analysis and Optimization of Organic Polymer Asymmetric Bent Waveguide
Gao Yuan, Zhang Xiaoxia, and Liao Jinkun
In order to reduce the length of polymer branch waveguide in Mach-Zehnder(M-Z) electro-optic polymer modulator, asymmetric sine-bend ridge waveguide is researched. The transmission loss of asymmetric sine-bend ridge waveguide under different parameters is systematically studied by using the full-vector finite-differencIn order to reduce the length of polymer branch waveguide in Mach-Zehnder(M-Z) electro-optic polymer modulator, asymmetric sine-bend ridge waveguide is researched. The transmission loss of asymmetric sine-bend ridge waveguide under different parameters is systematically studied by using the full-vector finite-difference beam propagation method (FD-BPM). The structure is optimized as ridge width w=4 μm, branch height h=11 μm, slab width on core layer of outboard bend s=2 μm, and length of the bend waveguide L=300 μm. The research results have shown that if the symmetric sine-bend ridge waveguide is replaced by asymmetric sine-bend ridge waveguide, the length of branch waveguide can reduce 40% under the same transmission-loss conditions. The results will have a certain reference value to the design of optical waveguide in polymer M-Z modulator..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 213002 (2011)
Fabrication of Silica-on-Silicon Arrayed Waveguide Gratings
Lang Tingting, Lin Xufeng, and He Jianjun
The arrayed waveguide grating is one of the key devices in integrated wavelength division multiplexing optical networks. In order to realize high performance arrayed waveguide gratings, it is essential to optimize the fabrication process of silica-on-silicon planar optical waveguides. A new process for filling the gapsThe arrayed waveguide grating is one of the key devices in integrated wavelength division multiplexing optical networks. In order to realize high performance arrayed waveguide gratings, it is essential to optimize the fabrication process of silica-on-silicon planar optical waveguides. A new process for filling the gaps of plasma enhanced chemical rapor deposition(PECVD) silica waveguides using boron-germanium co-doped upper-cladding and high-temperature annealing is proposed. And the measured transmission loss of an arrayed waveguide grating is reduced by about 2 dB. By reason of avoiding the use of toxic phosphine, the proposed method has potential advantages compared with the commonly used borophosphosilicate glass (BPSG) processing. Every step of fabrication, such as photolithography, PECVD, inductively coupled plasma (ICP) and high-temperature thermal annealing, is modified and improved. The excess loss of fabricated arrayed waveguide grating is about 1.5 dB..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 213003 (2011)
Threshold Conditions of GaAs Photoconductive Semiconductor Switch Operated in Lock-on Mode
Cui Haijuan, Yang Hongchun, Ruan Chengli, and Wu Minghe
As for semi-insulating GaAs photoconductive semiconductor switch (PCSS) operated in lock-on mode, threshold conditions of biased electric field and optical excitation energy are measured by a pulsed circuit. Experimental results show that the field threshold has an analogy to inverse exponential dependence on the opticAs for semi-insulating GaAs photoconductive semiconductor switch (PCSS) operated in lock-on mode, threshold conditions of biased electric field and optical excitation energy are measured by a pulsed circuit. Experimental results show that the field threshold has an analogy to inverse exponential dependence on the optical energy threshold. PCSS can be triggered into lock-on mode with 9 kV/cm when the optical energy is on the order of 10 μJ; and with the optical energy above 0.78 mJ, PCSS will be operated in linear mode but not lock-on mode for different voltages. On basis of the results, high-gain dipole domain model is proposed to analyze electric field and optical energy thresholds of the PCSS. The results from the experiments and calculation are in good agreement within the measurement error..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 213004 (2011)
Lasers and Laser Optics
Experimental Research on External Cavity-Based Spectral Beam Combining of Three-Er3+/Yb3+ Codoped Fiber Lasers
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The external cavity-based spectral beam combining of Er3+/Yb3+ codoped fiber lasers is studied experimentally by using laser diodes as pump sources and large-mode-area Er3+/Yb3+ codoped double-clad fiber lasers as the gain media. The external cavity is composed of a blazed grating, a Fourier transform lens and an outpuThe external cavity-based spectral beam combining of Er3+/Yb3+ codoped fiber lasers is studied experimentally by using laser diodes as pump sources and large-mode-area Er3+/Yb3+ codoped double-clad fiber lasers as the gain media. The external cavity is composed of a blazed grating, a Fourier transform lens and an output coupling mirror. With the external cavity, single fiber laser can produce wavelength-tunable output. The tunable range is 38 nm and the linewidth is less than 0.08 nm. Spectral beam combining of three fiber lasers is performed. The combined output power is 940 mW with the combining efficiency of 74.3%. The output beam profile is stable with good beam quality and the beam quality factor M2x in the horizontal direction is 1.320, slightly higher than that of individual laser output which is 1.204. When using Fourier transform lens with longer focal length, the combining potential of the system can be increased and the beam quality can be improved..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 214001 (2011)
Analysis of the Output Characteristics of High-Power Fiber Lasers after Spectral Beam Combination
Yin Suqin, and Zhang Bin
The propagation model for the spectral combining system of fiber laser beams by the volume Bragg grating (VBG) in the photo-thermal refractive (PTR) glass is built. Considering the surface distortion of the VBG by high-power lasers, the VBG is dealt with by splitting into slice and the wave equation is calculated iteraThe propagation model for the spectral combining system of fiber laser beams by the volume Bragg grating (VBG) in the photo-thermal refractive (PTR) glass is built. Considering the surface distortion of the VBG by high-power lasers, the VBG is dealt with by splitting into slice and the wave equation is calculated iteratively by using the finite-different Grank-Nicholson and sparse matrix methods. The intensity distribution, the combination efficiency and the power in the bucket of two fiber laser beams after spectral beam combination by the VBG with different deformations are simulated numerically. The thermal deformation effect of the VBG on the intensity distributions, the combination efficiency and the power in the bucket of the combined beam is analyzed quantitatively. The results show that the surface distortion of the VBG due to high-power lasers not only degrades the beam quality of the combined beam, but also decreases the combination efficiency of the spectral beam combining system dramatically..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 214002 (2011)
L-Band Variable Wavelength Erbium-Doped Fiber Laser Based on Over-Coupler
Yang Yang, Qiao Xueguang, Liu Yinggang, Zhou Rui, Zhang Jinghua, and Zhang Jing
The principles and characteristics of a novel fiber loop mirror (FLM), which is composed of polarization controller (PC) and an over-coupler whose coupling ratio is sensitive to wavelength are investigated. The notch depths and positions of loops′ reflection spectrum can be changed by adjusting the PC in the loops. TheThe principles and characteristics of a novel fiber loop mirror (FLM), which is composed of polarization controller (PC) and an over-coupler whose coupling ratio is sensitive to wavelength are investigated. The notch depths and positions of loops′ reflection spectrum can be changed by adjusting the PC in the loops. The linear cavity of the L-band variable wavelength fiber laser consists of high-birefringence fiber loops and the over-coupler fiber loops. The reflectivity of various wavelengthes and the laser gain are controlled by changing the states of the polarization controllers in the cavity. In the experiment, the stable output wavelength can be changed from 1564 nm to 1592 nm, over 28 nm tuning range. Within this range, the 3 dB line-width is less than 0.2 nm and the side mode suppression ratio (SMSR) is more than 40 dB..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 214003 (2011)
Output Characteristic Research of Inorganic Liquid Laser System Pumped with Laser Diode Array
Li Mi, Wang Yali, Li Chunling, Wang Jiao, and Liu Liqing
Lasing experiment of inorganic liquid system pumped bilaterally with laser diode array under flowing state is carried out, and the smooth quasi continuous-wave laser output for long time is achieved. The average laser output power is higher than 10 W when the pumping frequency is 300 Hz, and the optical to optical effiLasing experiment of inorganic liquid system pumped bilaterally with laser diode array under flowing state is carried out, and the smooth quasi continuous-wave laser output for long time is achieved. The average laser output power is higher than 10 W when the pumping frequency is 300 Hz, and the optical to optical efficiency is about 6%. The influence of pumping current, pumping frequency, output coupling ration and the rotate speed of magnetic pump on the laser average output power is researched, and the elementary academic analysis is carried out. The experience for the further lasing experimental research of the inorganic liquid laser system under flowing state is accumulated. At the same time, the preservation technology problem of inorganic laser liquid for long time is solved and the optical performance degradation for the inorganic laser liquid is avoided effectively. The experimental results show that the inorganic liquid laser system pumped by laser diode array can avoid heat deposition effectively at flowing state and obtain the smooth quasi continuous-wave laser output in long time..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 214004 (2011)
All-Normal-Dispersion Dissipative Soliton Ytterbium-Doped Fiber Laser Without Additional Filter
Zhang Zuxing, and Dai Guoxing
The generation of mode-locked dissipative soliton pulse from an all-fiber ytterbium-dope laser based on nonlinear polarization rotation without dispersion compensation and additional filter has been demonstrated experimentally and numerically. The formation of the dissipative soliton pulse is a self-consistent result oThe generation of mode-locked dissipative soliton pulse from an all-fiber ytterbium-dope laser based on nonlinear polarization rotation without dispersion compensation and additional filter has been demonstrated experimentally and numerically. The formation of the dissipative soliton pulse is a self-consistent result of various effects in the laser including positive fiber dispersion, nonlinearity, cavity transmission, gain saturation, and filtering over one cavity round trip. Stable mode-locked pulses with pulse energy of 1.1 nJ have been achieved. The operation of the dissipative soliton lasers is numerically simulated, which agrees with the experimental results..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 2, 214005 (2011)
Mechanism Research of Pulsed-Laser Induced Damage to CCD Imaging Devices
Qiu Dongdong, Zhang Zhen, Wang Rui, Jiang Tian, and Cheng Xiang′ai
Aiming at the phenomenon that irreversible bright line and all-field blank screen happens in the CCD irradiated by pulsed laser, the resistance between driving electrodes and substrate is measured, damage micro-morphological image of different layers in the facular area is observed, exported waveforms are detected, andAiming at the phenomenon that irreversible bright line and all-field blank screen happens in the CCD irradiated by pulsed laser, the resistance between driving electrodes and substrate is measured, damage micro-morphological image of different layers in the facular area is observed, exported waveforms are detected, and the damage mechanisms for CCD are analyzed in detail. The results show that high power pulse laser induces the ablation at different layers of CCD, and increases the dark current and leakage current, which leads the failure of the device..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 214006 (2011)
Four-Wave-Mixing Enhanced Multi-Wavelength Brillouin Erbium-Doped Fiber Laser
Jiao Lei, Song Yuejiang, and Zhang Xuping
A four-wave-mixing enhanced multi-wavelength Brillouin erbium-doped fiber laser, in which dispersion-shifted fiber is used as Brillouin gain medium is demonstrated. The gain spectrum of the laser is efficiently broadened by the parametric gain of four-wave-mixing between Stokes lines, then more high-order Stokes and anA four-wave-mixing enhanced multi-wavelength Brillouin erbium-doped fiber laser, in which dispersion-shifted fiber is used as Brillouin gain medium is demonstrated. The gain spectrum of the laser is efficiently broadened by the parametric gain of four-wave-mixing between Stokes lines, then more high-order Stokes and anti-Stokes lines are produced. The influences of the erbium-doped fiber amplifier power and the Brillouin pump power on the four-waves-mixing enhancement effect are also investigated. A stable multi-wavelength output with 39 waves is obtained with a 980 nm pump of 105 mW and a 1559 nm Brillouin pump of 8 dBm..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 214007 (2011)
Switching between Complete Synchronization and Generalized Synchronization in an Open-Loop Unidirectional Optical Chaos Synchronization System
Li Nengyao, Wu Jiagui, Wu Zhengmao, Ding Ling, Shen Jinting, and Xia Guangqiong
In an open-loop unidirectionally coupled chaotic system composed of an external cavity distributed feedback (DFB) semiconductor laser and an isolated DFB semiconductor laser, frequency detuning between two lasers can be controlled accurately by adjusting the bias current of transmitting laser carefully, and then the chIn an open-loop unidirectionally coupled chaotic system composed of an external cavity distributed feedback (DFB) semiconductor laser and an isolated DFB semiconductor laser, frequency detuning between two lasers can be controlled accurately by adjusting the bias current of transmitting laser carefully, and then the chaos synchronization state under different frequency detuning values can be investigated. The experimental results show that the system behaves with complete chaos synchronization (CCS) for frequency detuning within a small range (-0.19~0.95 GHz), where the highest correlation value of CCS is 0.84 and the highest correlation value of generalized chaos synchronization (GCS) is 0.78; once the frequency detuning is beyond this range, chaos synchronization will be switched from CCS to GCS. Therefore, synchronization switching between complete synchronization and generalized synchronization can be achieved by adjusting the bias current of transmitting laser. The theoretical simulations exhibit the similar variation tendency as that of the experimental results..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 214008 (2011)
Materials
Characters of Luminescence from Tm3+-Er3+-Yb3+ Tri-Doped Oxyfluoride Glass Ceramics
Han Wanlei, Jia Yutao, and Song Yinglin
Tm3+-Er3+-Yb3+-codoped transparent oxyfluoride glass ceramics containing NaYF4 nanocrystals are fabricated. The formation of NaYF4 nanocrystals in the glass ceramics is confirmed by X-ray diffraction. Absorption spectra and upconversion fluorescence emission spectra under 980 nm excitation are measured. Intense blue (4Tm3+-Er3+-Yb3+-codoped transparent oxyfluoride glass ceramics containing NaYF4 nanocrystals are fabricated. The formation of NaYF4 nanocrystals in the glass ceramics is confirmed by X-ray diffraction. Absorption spectra and upconversion fluorescence emission spectra under 980 nm excitation are measured. Intense blue (476 nm), green (520 and 550 nm) and red (651 and 668 nm) emissions are simultaneously observed. Upconversion blue emission is corresponding to the 1G4→3H6 transition of Tm3+; Upconversion green emissions are corresponding to the 2H11/2→4I15/2 and 4S3/2→4I15/2 transitions of Er3+, respectively; Red emissions are corresponding to the 1G4→3H4 of Tm3+ and 4I9/2→4I15/2 of Er3+. Under the invariable concentrations of Tm3+ and Yb3+, the diversification of tricolor light integral intensity is investigated by changing concentrations of Er3+. To obtain upconversion fluorescence mechanisms, upconversion fluorescence intensity versus LD pump power are analyzed in view of energy levels of rare-earthions..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 216001 (2011)
Research on Diffraction Enhancement of Dynamic Holographic Grating in C60-Doped Nematic Liquid Crystals
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Photorefractive diffraction gratings were studied in cells of homeotropicall-y aligned 4-cyano-4-pentyl-biphenyl (5CB) liquid crystals doped with buckminsterfullerene (C60) based on two-beam coupling (TBC) experiment. In the 20 μm thick NLC sample (grating spacing was Λ≈24 μm), the first-order diffraction efficiency ofPhotorefractive diffraction gratings were studied in cells of homeotropicall-y aligned 4-cyano-4-pentyl-biphenyl (5CB) liquid crystals doped with buckminsterfullerene (C60) based on two-beam coupling (TBC) experiment. In the 20 μm thick NLC sample (grating spacing was Λ≈24 μm), the first-order diffraction efficiency of the orientational PR grating was as high as 40%, and the distribution of the diffractive intensities was asymmetric. According to the volume-mediated photorefraction and surface-mediated photorefraction, a qualitative analysis that the electric field enhancemeat results from the surface charge modulation and Carr-Helfrich effect is proposed. The high first-order diffraction efficiency obtained from the thin grating in NLC is probably attributed to the non-sinusoidal modulated space-charge field. The simulation results are in good agreement with the experimental results and also confirmed the physical mechanism..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 216002 (2011)
Study on Optical Properties of Kerosene-Based Fe3O4 Magnetic Liquid Film
Lu Zhangxian, Wang Jun, and Xia Sihua
The purpose is to study the linear birefringence and dichroism properties of the kerosene-based Fe3O4 magnetic fluid under the magnetic field, which have been theoretically analyzed and simulated numerically based on the dipole oscillation model. The experimental platform is designed to test the optical properties of kThe purpose is to study the linear birefringence and dichroism properties of the kerosene-based Fe3O4 magnetic fluid under the magnetic field, which have been theoretically analyzed and simulated numerically based on the dipole oscillation model. The experimental platform is designed to test the optical properties of kerosene-based Fe3O4 magnetic liquid in different volume densities under the magnetic field. The theory and numerical simulation show that the birefringence and dichroism of different polarized light have different variation trend under the magnetic field: the birefringence and dichroism of parallel polarized light decrease, but the ones of perpendicular polarized light increase; those are in proportion to the volume density; the transmittance in the interface between glass and ferrofluids is almost unchangeable. The experimental result is in agreement with the numerical simulation that provides the theoretical and experimental basis for designing the light switch and the application in measurement of the magnetic field and current sensors..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 216003 (2011)
Influence of Polarization State on Laser-Induced Domain Nucleation in Doped Lithium Niobate
Hou Peipei, Zhi Yanan, Sun Jianfeng, and Liu Liren
The influence of polarization state on laser-induced domain nucleation in Mg-doped and Hf-doped LiNbO3 is investigated. The phase distributions during laser-induced domain nucleation are reconstructed by digital holographic interferometry. The comparisons of nucleation field with different polarization states includingThe influence of polarization state on laser-induced domain nucleation in Mg-doped and Hf-doped LiNbO3 is investigated. The phase distributions during laser-induced domain nucleation are reconstructed by digital holographic interferometry. The comparisons of nucleation field with different polarization states including linear polarization, circular polarization and elliptical polarization are performed. The generated space-charge field along z direction is thought to be important mechanism. Not only the essential information for the future optimization of laser-induced domain engineering is provided, but also the new experimental evidences for the future mechanism investigation of laser-induced domain nucleation are supplied..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 216004 (2011)
PbSe Quantum Dot-Doped Sodium-Aluminum-Borosilicate Glass Fabricated by a Melting Method
Cheng Cheng, Jiang Huilü, and Ma Dewei
As a novel optical communication material, quantum dot (QD)-doped glass became one of the focal researches in recent years. PbSe QD-doped sodium-aluminum-borosilicate glass is fabricated successfully by the melting method. The crystallization, size and distribution of the PbSe QD in the glass are investigated by X-ray As a novel optical communication material, quantum dot (QD)-doped glass became one of the focal researches in recent years. PbSe QD-doped sodium-aluminum-borosilicate glass is fabricated successfully by the melting method. The crystallization, size and distribution of the PbSe QD in the glass are investigated by X-ray diffractometer and transmission electron microscopy. The absorption and photoluminescence (PL) spectra of the PbSe QD doped-glass are also observed by UV-visible-NIR spectrophotometer and fluorescence spectrometer, respectively. The obtained results suggest that, when heat treatment temperature T is lower than 500 ℃, there is no observed PL emission in glass under irradiation of 1064 nm laser. When treatenent temperature T>550 ℃, the glass appears strong PL emissions with full width at half maximum (FWHM) in the range of 275~808 nm, and the PL peak wavelengths in 1676~2757 nm region strongly depended on the QD size. The size of PbSe QD is positively correlated with the heat treatment temperature, a Stokes shift of between the absorption and PL peaks is 20~110 nm..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 216005 (2011)
Enhancement of Luminescent Properties in Li+ Codoping Er3+:Y2O3 Nanocrystals Synthesized by Combustion Method
Lü Jiantao, Wang Kejia, Liu Jinsong, Zhang Qingquan, Zhu Qihua, Zeng Xiaoming, and Yao Jianquan
Er3+:Y2O3 nanocrystals codoping with Li+ are prepared by glycine combustion method. The samples are characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) and photoluminescent measurements. Effect of the Li+ molar fraction on the structure and the fluorescence intensity of the naEr3+:Y2O3 nanocrystals codoping with Li+ are prepared by glycine combustion method. The samples are characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) and photoluminescent measurements. Effect of the Li+ molar fraction on the structure and the fluorescence intensity of the nanocrystals are investigated. The XRD result indicates good crystallinity. The luminescent test results show that with the increase of the Li+ codoping fraction, the fluorescence intensity of the nanocrystals around 1.5 μm enhances remarkably. The luminous efficiency of Er3+ is increased by codoping Li+, which can modify the lattice symmetry of the nanocrystals..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 216006 (2011)
Effect of Substitution of Dy3+ on Structure and Luminescence Properties of Y3Al5O12:Ce3+
Mu Zhongfei, Hu Yihua, Wang Yinhai, Wu Haoyi, Fu Chujun, and Kang Fengwen
A series of samples with the composition Y2.95－xDyxAl5O12:Ce3+0.05(x＝0，0.59，1.18，1.77，2.36，2.95) are prepared by high-temperature solid-phase method. The structure of samples is studied by X-ray powder diffraction method. The results show that crystal lattice of the host expands when Y3+ is substituted by Dy3+, and theA series of samples with the composition Y2.95－xDyxAl5O12:Ce3+0.05(x＝0，0.59，1.18，1.77，2.36，2.95) are prepared by high-temperature solid-phase method. The structure of samples is studied by X-ray powder diffraction method. The results show that crystal lattice of the host expands when Y3+ is substituted by Dy3+, and the expansion is proportional to the amount of Dy3+ which substitutes Y3+. The photoluminescence analysis shows that the substitution results in red shift of emitting peak position and the red shift is also proportional to the value of x. All the samples show yellow long afterglow after they are excited by ultraviolet light. The afterglow time decreases with the value of x. The thermoluminescence analysis shows that there are two kinds of traps with different depths in the host crystal lattice. The substitution of Dy3+ does not change the sorts of traps but it is able to lower the energy level of the traps which is advantageous to the release of electrons in the traps at room temperature..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 216007 (2011)
Nonlinear Optics
Research on Time-Delay Characteristics of Solitons in Fiber Bragg Grating
Wang Kuiru, Cheng Jielin, Chen Gong, Rao Lan, and Sang Xinzhu
Based on slow light theory and nonlinear coupled-mode equations of fiber Bragg grating, the characteristics of the velocity when Bragg grating (BG) solitons transmitting through fiber Bragg grating (FBG) are simulated. The time delay of the BG solitons is measured by an experimental system, which based on the high-speeBased on slow light theory and nonlinear coupled-mode equations of fiber Bragg grating, the characteristics of the velocity when Bragg grating (BG) solitons transmitting through fiber Bragg grating (FBG) are simulated. The time delay of the BG solitons is measured by an experimental system, which based on the high-speed oscilloscope. The time delay of the high-intensity narrow pulses propagating in the BG is acquired. The results show that, with BG on ordinary signal-mode fiber of 5 cm long, the time-delay is 426 ps and its speed is 1.17×108 m/s, and that in other case, when the fiber has high nonlinearity, the time delay is 1.639 ns, and the speed of the BG soliton is 0.31×108 m/s. Thus, the deceleration of the BG soliton is possible, and the velocity with that the soliton tansmitts through the high nonlinear FBG is lower than that through the ordinary signal-mode FBG..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 219001 (2011)
Study on Modulation Instability of Broad Polychromatic Beams in Photovoltaic Crystal
Peng Xiaolan, Zhou Yamin, and Wang Hongcheng
The modulation instability of two broad beams with different frequencies is investigated in a photovoltaic photorefractive crystal with a uniform background illumination. It is shown that modulation instability of broad polychromatic beams can be adjusted and controlled by the Glass coefficient ratios (r1, r2) of the sThe modulation instability of two broad beams with different frequencies is investigated in a photovoltaic photorefractive crystal with a uniform background illumination. It is shown that modulation instability of broad polychromatic beams can be adjusted and controlled by the Glass coefficient ratios (r1, r2) of the signal and background beams. It is also found that the strength of modulation instability depends on the ratio of beam intensities f and g. For the case of r1>1,r2>1, the maximum modulation instability gain increases first and then decreases with the increase of g when f<0.5, while it decreases monotonically when f>0.5. For large g, the modulation instability is suppressed and tends to be 0. For the case r1>1,r2<1, the signal beam whose r2 is less than 1 can suppress the modulation instability of the other signal beam whose r1>1 when f<4. If f>4, the modulation gain is always very small. For the case r1<1,r2<1, the polychromatic broad beams do not undergo modulation instability..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 219002 (2011)
Preparation Technique of Negative-Electron-Affinity GaN Photocathode
Guo Xiangyang, Wang Xiaohui, Chang Benkang, Zhang Yijun, and Qiao Jianliang
By making use of the self-developed ultrahigh vacuum activation system and surface analysis system, the validity of GaN (0001) chemical cleaning formula is confirmed by X-ray photoelectron spectroscopy (XPS) analysis. The heating cleaning technique to clean atom surface is proved to be correct by activated result. The By making use of the self-developed ultrahigh vacuum activation system and surface analysis system, the validity of GaN (0001) chemical cleaning formula is confirmed by X-ray photoelectron spectroscopy (XPS) analysis. The heating cleaning technique to clean atom surface is proved to be correct by activated result. The activation technique combining Cs single activation with follow-up Cs /O alternative activation is established by integrating light current changing curve in the activation process. GaN photocathode whose surface achieves negative electron affinity (NEA) is prepared successfully. After the activation, the spectral response is measured by the illumination of optical fiber. The whole preparation technique is proved to be correct true according to quantum efficiency curve obtained by calculation. The technique process of preparing NEA GaN photocathode is established through a series of experments..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 219003 (2011)
Optical Design and Fabrication
Alignment of off-Axis Conic Aspheric Mirrors in Stigmatic Null Test
Chen Qinfang, Li Yingcai, Ma Zhen, Li Xuyang, and Liang Shitong
During interferometric testing, an accurate evaluation of the surface information is one of the key factors in realizing deterministic manufacturing of off-axis aspheric mirrors. The method used in the analysis of wavefront aberration due to centring error in optical system is valid for test piece misalignment in an inDuring interferometric testing, an accurate evaluation of the surface information is one of the key factors in realizing deterministic manufacturing of off-axis aspheric mirrors. The method used in the analysis of wavefront aberration due to centring error in optical system is valid for test piece misalignment in an interferometric setting as well. The mathematic model of error separation is developed. In experiment, the test result of an off-axis aspheric mirror after alignment is 0.037λ (RMS, λ=0.6328 μm), the test efficiency is improved effectively..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 222001 (2011)
Experimental Research of Spectral Design of Solar Simulator
Chen Wenzhi, Jiang Lulin, Jiang Li, Wang Hong, and Zhou Qi
The spectral test of solar simulator is carried out. The test result shows that the energy of the spectra from 800 to 900 nm and from 900 to 1100 nm which are radiated by the xenon lamp from solar simulator without laying optical filter occupies too much percentage of the whole spectra and is greater than that of the iThe spectral test of solar simulator is carried out. The test result shows that the energy of the spectra from 800 to 900 nm and from 900 to 1100 nm which are radiated by the xenon lamp from solar simulator without laying optical filter occupies too much percentage of the whole spectra and is greater than that of the international standard code matching limit. Then it results in that the relatively spectral distribution of energy cannot fulfil the demand of A or B grade, which seriously affects the solar cell test result. So solar simulator needs to lay special designed optical filter to remedy the spectra, and the optical filter can filter or weaken energy of infrared band and fulfil the spectral demand of A or B grade. By optimal design of optical filter, we can make the spectrum to reach optimal uniformity..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 222002 (2011)
Design of High Numerical Aperture Projection Objective for Industrial Extreme Ultraviolet Lithography
Liu Fei, and Li Yanqiu
Extreme ultraviolet lithography (EUVL) is the next generation lithography for the semiconductor manufacturer to achieve 22 nm node and below. Design of the projection objective is a core technology for the high-resolution lithography. An optical projection system with six high-order aspheric mirrors is presented to meeExtreme ultraviolet lithography (EUVL) is the next generation lithography for the semiconductor manufacturer to achieve 22 nm node and below. Design of the projection objective is a core technology for the high-resolution lithography. An optical projection system with six high-order aspheric mirrors is presented to meet the industrial needs of the extreme ultraviolet lithography at 22 nm node. In the catoptrics embodiment of the present design, an image numerical aperture of 0.3 and a field width of 1.5 mm are obtained resulting in a working resolution of 25 nm across the exposure field, while the depth of focus is greater than 75 nm and modulation transfer function (MTF) larger than 45% without any resolution enhancement technologies. The mean wave front error of 0.0228λ (RMS) is reached. And the distortions of all field points are below 1.6 nm, CD (critical dimension) error is smaller than 1.6% while it is partial coherently illuminated (partial coherent factor 0.5～0.8). The total length of the system is 1075 nm. Image working distance is above 30 mm. Combined with resolution enhancement technologies, such as off-axis illumination or phase-shift mask, a greater depth of focus for 22 nm resolution can be achieved within the photoresist to meet extreme ultraviolet lithography lens industry need with 22 nm nodes..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 222003 (2011)
Third-Order Aberration Correction of Two-Mirror Optical Systems with Zero-Optical Power Corrector
Hao Peiming, Li Kexin, and Yuan Liyin
Zero-power corrector can be applied in two-mirror system to enhance aberration correction ability or avoid using aspheric optics. There are seven variables in this kind of system, which is helpful for aberration correction and has no chromatism. Based on the third-order aberration theory, normalized method and paraxialZero-power corrector can be applied in two-mirror system to enhance aberration correction ability or avoid using aspheric optics. There are seven variables in this kind of system, which is helpful for aberration correction and has no chromatism. Based on the third-order aberration theory, normalized method and paraxial function, the aberration characteristic of systems with a zero-optical power corrector which located in front of the mirrors is analyzed, and kinds of third-order aberration correction formula are given. The analysis is confirmed by a design sample with optical design software. It will greatly benefit optical designer for the design of this kind of system..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 222004 (2011)
Optical Devices
A Study on Effective Path Length Ratio for Waveguide Absorption Cell
Zhou Jiaqi, and Shi Yiwei
Optical waveguide has a promising application as absorption cell in concentration measurement of gases and liquids. The sensitivity of the measuring system is directly proportional to the effective path length (EPL) of the absorption cell. A mathematical model is proposed for the EPL of various kinds of waveguides. TheOptical waveguide has a promising application as absorption cell in concentration measurement of gases and liquids. The sensitivity of the measuring system is directly proportional to the effective path length (EPL) of the absorption cell. A mathematical model is proposed for the EPL of various kinds of waveguides. Theoretical analysis is made for the dependence of EPL on the waveguide parameters such as inner-coated film thickness and film refractive index, bore-diameter and bending radius, and intensity distribution of incident light. Several important results are obtained from the simulations, which provide optimizing parameters for the sensing system and algorithms for error compensation. Calculation results have shown good agreement with published measured data..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 223001 (2011)
A New Method of Improving Frequency Selective Surface Passband Transmittance
Zhu Huaxin, Gao Jinsong, Feng Xiaoguo, Zhao Jingli, Liang Fengchao, Wang Yansong, and Chen Xin
Based on a Y loop element, a new method which sets circular slot on the periodic element to improve frequency selective surface (FSS) structure of narrow bandwidth and high transmittance is presented. The FSS structure is calculated by Galerkin′s method in spectral domain. The optimum radius is 0.4 mm, and the numbers Based on a Y loop element, a new method which sets circular slot on the periodic element to improve frequency selective surface (FSS) structure of narrow bandwidth and high transmittance is presented. The FSS structure is calculated by Galerkin′s method in spectral domain. The optimum radius is 0.4 mm, and the numbers of the circular slot is 12. The resonance frequency is 15 GHz, and its transmittance is increased 0.12 dB. The plane sample is fabricated by depositing coatings and lithography. The agreement between the calculated and measured values is good. Compared with the Y loop without circular slot, the results show that the transmittance of this structure which is about -0.69 dB at the resonance frequency increased 0.16 dB under the normal incidence. The transmittance at TE 30° and 45° incidence are -0.64 dB and -0.78 dB, respectively. Compared with the Y loop without circular slot, the transmittance are increased about 0.345 dB and 0.31 dB, respectively. And the bandwidth difference between the two structures is negligible, and they are about 1.26 GHz and 0.97 GHz under TE 30° and 45° incidence, respectively. So this method is an effective way to improve the transmittance of large periodic FSS structure at resonance frequency..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 223002 (2011)
Remote Sensing and Sensors
Analysis of Target Location Accuracy in Space-Based Optical-Sensor Network
Sheng Weidong, Long Yunli, and Zhou Yiyu
An novel analysis method of target location accuracy of multiple factors is proposed for the space-based optical sensor network. A measurement model is established using the transformation from target stereo position to focal plane. Then, possible error sources about target location are analyzed. By introducing the linAn novel analysis method of target location accuracy of multiple factors is proposed for the space-based optical sensor network. A measurement model is established using the transformation from target stereo position to focal plane. Then, possible error sources about target location are analyzed. By introducing the line-of-sight vector in the earth-centered inertial coordination as a temporary variable, error transmission matrices among the target stereo poistion, the line-of-sight and the target measurement position in the focal plane are derived. Furthermore, a theoretical analysis model of target location accuracy is established based on least squared criterion. The efficiency of this analysis model is verified by Monte Carlo simulation. Some results could provide references for engineering applications, e.g. multiple-sensor management..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 228001 (2011)
An Algorithm of Cluster Tracking for Midcourse Ballistic Object Group by Infrared Multi-Sensor Based on Probability Hypothesis Density Filtering
Lin Liangkui, Xu Hui, Long Yunli, An Wei, and Xie Kai
The essentiality of cluster tracking for midcourse ballistic target group by low earth orbit(LEO) optical constellation is analyzed. And an improved method of cluster tracking is presented. The probability hypothesis density filter is used to track multi-target on the focal plane, filter out clutter, and estimate targeThe essentiality of cluster tracking for midcourse ballistic target group by low earth orbit(LEO) optical constellation is analyzed. And an improved method of cluster tracking is presented. The probability hypothesis density filter is used to track multi-target on the focal plane, filter out clutter, and estimate target number and state. Then for improving the stability of focal plane target tracking, an image registration method is adopted to adjust interframes target state estimation. Finally, the focal plane 2D centroid measurement of target group is computed based on the focal plane tracking results, and unscented Kalman filter(UKF) is adopted to track the 3D centroid of target group through multi-sensor fusion in sequence. Simulation results show that, the proposed method works well under different clutter rates, and gains a better precision than the traditional one. Meanwhile, it successfully realizes the tracking of each target on the space-based infrared focal plane..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 228002 (2011)
Scattering
Optical Constants Deduction and Scattering Bidirectional Reflectance Distribution Function Computation of Alloy Aluminum Surface in Near Infrared Waveband
Yang Yufeng, Wu Zhensen, and Cao Yunhua
Polishing alloy aluminum sample′s specular reflection spectrum in waveband 0.5~1.5 μm is measured by spectrophotometer, then it can be extrapolated to the all band by using constant and power function extrapolation. According to Kramers-Kronig(K-K) method, complex refractive index and dielectric constant of this samplePolishing alloy aluminum sample′s specular reflection spectrum in waveband 0.5~1.5 μm is measured by spectrophotometer, then it can be extrapolated to the all band by using constant and power function extrapolation. According to Kramers-Kronig(K-K) method, complex refractive index and dielectric constant of this sample in waveband 0.5~2.5 μm are deduced, this result well coincides with ellipsometer′s data in waveband 0.5~1.5 μm. The rough alloy aluminum sample′s scattering bidirectional reflectance distribution function(BRDF) at 1.06 μm is calculated using Kirchhoff method and deduced dielectric constant, which well coincides with BRDF measurer′s data. Roughness parameters and dielectric constants extrapolated in waveband 1.5~2.5 μm is used to calculate scattering BRDF of the rough alloy aluminum sample in this waveband..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 229001 (2011)
Spectroscopy
Rapid Detection of the Degradation of the Typical Pollutants from ABS Wastewater Using Fourier Transform Infrared Spectroscopy
Lai Bo, Qin Hongke, Zhou Yuexi, Pang Cuicui, Xu Jixian, Lian Yu, Zhang Sheng, and Zhou Jihong
In order to decompose and transform the toxic refractory typical pollutants from ABS resin wastewater, this wastewater was pretreated by the micro-electrolysis. The decomposition and transformation of the typical pollutants from ABS wastewater was detected by Fourier transform infrared (FTIR). The results show that thoIn order to decompose and transform the toxic refractory typical pollutants from ABS resin wastewater, this wastewater was pretreated by the micro-electrolysis. The decomposition and transformation of the typical pollutants from ABS wastewater was detected by Fourier transform infrared (FTIR). The results show that those typical pollutants, such as acrylonirile, styrene, alpha, alpha-dimethyl-benzenemethanol, acetophenone, 3,3′-oxybis-propanenitrile and 3,3′-iminobis-propanenitrile, could be decomposed and transformed by the micro-electrolysis under the condition of the influent pH value of 4.0. The degradation products of those typical pollutants were small molecule organic compounds such as unsaturated fatty acids, alcohols or acylamides. And the BOD/COD ratio of ABS resin wastewater was increased from 0.32 to 0.71 after the treatment of micro-electrolysis, in other words, the biodegradability of ABS resin wastewater was increased significantly..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 230001 (2011)
Simultaneous and Rapid Quantitative Analysis of Four Components in Cordyceps Militaris Mycelium Powder Using Near Infrared Spectroscopy
Guo Weiliang, Wang Dan, Song Jia, Lu Jiahui, Du Linna, and Teng Lirong
Near infrared (NIR) spectroscopy calibration models have been developed for simultaneous and rapid determining the adenosine, protein, polysaccharide and cordyceps acid contents in cordyceps militaris mycelium powder. Cordyceps militaris mycelium powder samples are collected by culturing different cordyceps militaris mNear infrared (NIR) spectroscopy calibration models have been developed for simultaneous and rapid determining the adenosine, protein, polysaccharide and cordyceps acid contents in cordyceps militaris mycelium powder. Cordyceps militaris mycelium powder samples are collected by culturing different cordyceps militaris mutant strains under various cultured conditions and the NIR spectra are acquired. Radial basis function neural network (RBFNN) is used for modeling the relation between the NIR spectra and the adenosine, protein, polysaccharide and cordyceps acid contents. The RBFNN models have been optimized. Firstly, movable window method is employed to select characteristic wavelength variables. And then, spectra preprocessing methods, the number of hidden nodes and the spread constant are selected. The optimum RBFNN models for determining the adenosine, protein polysaccharide and cordyceps acid contents are obtained. The correlation coefficients (Rc) between reference values of calibration set and the predictive values are 0.9436, 0.9884, 0.9018 and 0.8848, respectively, which indicate that the fit of these models is satisfying. The root mean square error of prediction set (RMSEP) RMSEP are 0.6225 mg/g, 0.0179 g/g, 0.0115 g/g, and 0.0102 g/g, respectively, which indicate that the predictive capabilities of the models are fine..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 230002 (2011)
Thin Films
Anti-Ultraviolet Radiation of Antireflection Coatings for Display Plastics
Wu Jiang, Shen Weidong, Yuan Wenjia, Zhang Yueguang, and Gu Peifu
Anti-ultraviolet radiation of antireflection coatings on display plastics is presented. For polycarbonate (PC) substrate which is one of the commonly used plastics, the calculated average reflectance at normal incidence in ultraviolet region of 300~380 nm is greater than 99.5% and the residual reflectance in visible reAnti-ultraviolet radiation of antireflection coatings on display plastics is presented. For polycarbonate (PC) substrate which is one of the commonly used plastics, the calculated average reflectance at normal incidence in ultraviolet region of 300~380 nm is greater than 99.5% and the residual reflectance in visible region of 420~750 nm is 0.22%. The reflectance at 45° incidence in ultraviolet region of 300~360 nm is greater than 98.5% and that in visible region of 400~700 nm is 0.71%. The adhesion and stress of coatings on plastics are discussed. It is proved by experimental results that all of the properties, e.g., the anti-ultraviolet radiation, the antireflection, the wide incident angle and the durability of the coatings on plastics can be used for practical display applicaitons..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 231001 (2011)
Thermal Analysis of Polymer Electroluminescent LED Surface Light Source
Zhang Jianping, Zou Jianhua, and Wen Shangsheng
For structural characteristics of polymer light-emitting diode (PLED) surface light source, thermal model of dual-channel is built. By using finite element analysis software, the thermal properties of PLED surface light source is simulated in the light intensity of 1000 cd/m2, and temperature distribution is obtained uFor structural characteristics of polymer light-emitting diode (PLED) surface light source, thermal model of dual-channel is built. By using finite element analysis software, the thermal properties of PLED surface light source is simulated in the light intensity of 1000 cd/m2, and temperature distribution is obtained under natural convection and forced convection. The simulation results show that the highest temperature is in PFO-BT emitting layer of the PLED surface light source with temperature of 43.934 ℃ and 26.234 ℃ respectively. By simulating the whole process from the beginning to the light intensity of 5000 cd/m2, the linear relation between the highest temperature TH and input power P is gained. By changing the electrode shape and size of aperture opening ratio of PLED surface light source respectively, the influence of these factors on thermal characteristics of PLED surface light source is obtained. The simulation results reveal that the electrode shape is one of the most important factors to the highest temperature TH of PLED surface light source, and using circular electrode can promote the dissipation of heat of PLED surface light source effectively. As the aperture opening ratio increases, the highest temperature TH of PLED surface light source increases steadily, but they do not present a simple linear relationship. These results provide a basis for the optimization of PLED surface light source..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 2, 231002 (2011)
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