Contents
2011
Volume: 31 Issue 4
48 Article(s)
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Atmospheric Optics and Oceanic Optics
Refraction Effects on Electro-Optical Target Characteristic in Near Sea Surface
Li Yunbo, Fang Zheng, Zhang Yonggang, and Wang Huili
When detecting and tracking the low-sky targets (lower than 50 m) such as boats, sea-skimming missile and airplane, visible and infrared electronic optical (EO) systems could be highly affected by atmospheric refraction. The distance from the apparent horizon to an observer can be lengthened or shortened, especially miWhen detecting and tracking the low-sky targets (lower than 50 m) such as boats, sea-skimming missile and airplane, visible and infrared electronic optical (EO) systems could be highly affected by atmospheric refraction. The distance from the apparent horizon to an observer can be lengthened or shortened, especially mirage will increase the false alarm odds and the disturbance of detecting and tracking of targets. This paper established optical propagation evaluation model based on air-sea flux algorithm and ray tracing program. Using EO detection trial data in the Northern Yellow Sea, from November to December, 2009, evaluated characteristic refractive heights, the maximum inter-visvion ranges (MIVR) as well as some relevant EO propagation parameters, simulated the marine multi-objective image, and has verified the model performance. The model accuracy of MIVR is better, the target image on different distance is simulated accurately..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 401001 (2011)
Research on Atmospheric Refraction Correction Algorithm and Model for Satellite Laser Range-Finding
Yuan Hongwu, Mei Haiping, Huang Yinbo, and Rao Ruizhong
Considering the influences of atmospheric refraction on the satellite laser ranging, an algorithm for calculating the optical path differences based on ray tracing is studied. Firstly, the annual mean atmospheric refractivity modulus height profiles of 46 typical regions in China are fitted by using meteorological sounConsidering the influences of atmospheric refraction on the satellite laser ranging, an algorithm for calculating the optical path differences based on ray tracing is studied. Firstly, the annual mean atmospheric refractivity modulus height profiles of 46 typical regions in China are fitted by using meteorological sounding datum and high level model datum synthetically. Secondly, the results calculated by the Marini-Murray model and ray tracing which is based on the monthly average model and the annual mean model are compared and analyzed. Then, the national distribution of the optical path difference of satellite laser ranging is presented. Finally, the relations between the optical path difference with the height above sea level of ranging site and the elevation of satellite are numerically investigated..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 401004 (2011)
Detectors
High-Accuracy Ultraviolet Standard Radiometer
Wang Rui, Wang Shurong, Guo Jin, Wang Tingfeng, and Zhang Zhenduo
After adding the beam-splitting and data-acquisition system, a set of high-accuracy ultraviolet standard radiometer (HAUSR) with self responsibility standard is constructed by using the standard detector of National Institute of Standards and Technology(NIST) as core element. The core elements of HAUSR have been testedAfter adding the beam-splitting and data-acquisition system, a set of high-accuracy ultraviolet standard radiometer (HAUSR) with self responsibility standard is constructed by using the standard detector of National Institute of Standards and Technology(NIST) as core element. The core elements of HAUSR have been tested. With the responsibility of the standard detector known, the responsibility standard of HAUSR had been deduced by theoretical derivation and adding corresponding correction factor. The accuracy (to 1.3%) of HAUSR is analyzed. It proves the HAUSR system has fine stability, high accuracy and self responsibility standard..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 404001 (2011)
Development of Multi-Band Radiance Standard Transfer Detector
Zou Peng, Zheng Xiaobing, Wu Haoyu, Li Xin, Xie Ping, Li Jianjun, and Liu Enchao
In order to provide radiance reference based on standard detector and improve the calibration accuracy of remote sensor, a multi-band radiance standard transfer detector (MRSTD) based on trap structure has been developed. There are eight channels in MRSTD and the aperation wavelengths of MRSTD are from 400 to 1000 nm. In order to provide radiance reference based on standard detector and improve the calibration accuracy of remote sensor, a multi-band radiance standard transfer detector (MRSTD) based on trap structure has been developed. There are eight channels in MRSTD and the aperation wavelengths of MRSTD are from 400 to 1000 nm. A Si trap detector is used for radiometric power measurement, an interference filter is used to limit the spectral band of the incident light, and a field stop and an aperture stop are used to limit receiving area and solid angle of the input flux. A weak current detection circuit is designed to measure the photocurrent of the detector accurately. The filter and the detector are temperature controlled by a closed-loop control system. The principle and development process of the facility are introduced and the uncertainties of its absolute spectral radiance responsivity are evaluated in detail. The relative uncertainty of MRSTD is less than 1.26%..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 404002 (2011)
Diffraction and Gratings
Simplified Model for Mask Diffraction in Extreme-Ultraviolet Projection Lithography
Cao Yuting, Wang Xiangzhao, Qiu Zicheng, and Peng Bo
A simplified model is built to calculate the mask diffraction field in extreme-ultraviolet lithography. In this model, the analytical expression of the diffraction fields is derived by incident-ray tracing. The mask in the simplified model includes two parts, the multilayer structure and the absorber layer structure. TA simplified model is built to calculate the mask diffraction field in extreme-ultraviolet lithography. In this model, the analytical expression of the diffraction fields is derived by incident-ray tracing. The mask in the simplified model includes two parts, the multilayer structure and the absorber layer structure. The diffraction of multilayer is approximated as mirror reflection, and the diffraction field of the absorber layer is calculated using the modified thin mask model, where the absorber layer is equivalent to a thin mask located on a certain plane. The boundary pulse represents the boundary diffraction-wave effects. The geometric-optical wave through the absorber layer is modified by determining the position of the thin mask plane and the amplitude and phase of the boundary pulse. This modified thin mask model for the absorber layer can be used for 11 nm line/space patterns with oblique incident angles no more than 12°. Taking 22 nm dense lines pattern at 6° incident angle as an example, the results of the simplified extreme-ultravilet lithography mask model are consistent with the rigorous simulation..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 405001 (2011)
Fabrication of Convex Blazed Grating By Ar+ Ion-Beam Etching
Wang Haibin, Liu Quan, and Wu Jianhong
Convex blazed grating is one of the most important devices in hyperspectral imaging spectrometers. The major application obstacle is the huge gap between the diffraction efficiency which is obtained from the experiment and that in theory. The bottleneck lies in the small blazing angles required in the manufactory. To sConvex blazed grating is one of the most important devices in hyperspectral imaging spectrometers. The major application obstacle is the huge gap between the diffraction efficiency which is obtained from the experiment and that in theory. The bottleneck lies in the small blazing angles required in the manufactory. To solve this problem, a convex blazed grating is made by adopting an argon ionbeam to directly etch the substrate through a photoresist mask. Considering the potential inconsistent blazing angles across the whole convex grating area with big glancing angle, the blazed grating etching of spherical surface is realized by using a circular scanning etching. A grating of a small blazing angle of 4.3° is fabricated. The average efficiency of the first order diffracted beams is more than 40% in the visible wavelength range..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 405002 (2011)
Polarizing Color Filter Based on a Submicron Metal Grating
Ye Yan, Zhou Yun, Zhang Heng, Shen Su, and Chen Linsen
A polarizing color filter based on one-dimensional (1D) subwavelength patterned metal grating combining the function of polarizer and color filter is proposed. The proposed device is consisted of three parts as a substrate, a dielectric grating-layer and a metal grating. The effects of the dielectric grating-layer and A polarizing color filter based on one-dimensional (1D) subwavelength patterned metal grating combining the function of polarizer and color filter is proposed. The proposed device is consisted of three parts as a substrate, a dielectric grating-layer and a metal grating. The effects of the dielectric grating-layer and the metal grating are investigated in detail by rigorous coupled-wave analysis (RCWA) and its performance is enhanced effectively by utilizing a dielectric grating of high equivalent refractive index. Typical optimized structural parameters are obtained, in which more than 72.6% broadband transmission with greater than 40 dB polarization extinction ratio have been achieved simultaneously for tricolor filter. For the red color filter, the center wavelength is 650 nm and its corresponding transmittance is 72.60% for the green color one, the central wavelength is 550 nm and its corresponding transmittance is 79.86%, while for the blue color one, the central wavelength is 445 nm and its corresponding transmittance is 77.00%. The transmittance can be increased to 117.8％ with the recycle of the TE-polarized light..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 405003 (2011)
All-Optical RZ to NRZ Format Conversion Based on Fiber Cross-Phase Modulation
Meng Xiaojun, Yan Lianshan, Pan Wei, Luo Bin, Yi Anlin, and Li Liguang
All-optical RZ to NRZ format conversion based on cross-phase modulation in the high-nonlinearity fiber is numerically simulated. Performances of converted NRZ signals from RZ data streams with different duty cycles are analyzed and compared. Results indicate that the duty cycle of RZ data does affect the converted NRZ All-optical RZ to NRZ format conversion based on cross-phase modulation in the high-nonlinearity fiber is numerically simulated. Performances of converted NRZ signals from RZ data streams with different duty cycles are analyzed and compared. Results indicate that the duty cycle of RZ data does affect the converted NRZ signal, with a rational value between 30% and 50%. Meanwhile, RZ to NRZ format conversion is experimentally demonstrated at 10 Gb/s data rate with 33% duty cycle. Signal spectrum before and after HNLF, typical eye diagrams and bit-error-rate (BER) are measured. Less than power penalty 1 dB is obtained in bit error rate 10-9 after the format conversion. Further experimental results confirm the feasibility in 160 Gb/s high-speed systems..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 406005 (2011)
Fiber Optics and Optical Communications
Bidirectional Oscillations in Fiber Ring Laser Gyroscope with Polarization Splitting Filter
Rao Fanjun, Chen Shufen, Fu Lei, and Zou Zhengfeng
A type of fiber ring laser gyroscope based on a polarization splitting filter is presented, and its principle of bidirectional operation and the generation of beat frequency is analyzed. The mode energy coupling can be adjusted by controlling the filter. When the pump power exceeds 10 mW, bidirectional single-mode osciA type of fiber ring laser gyroscope based on a polarization splitting filter is presented, and its principle of bidirectional operation and the generation of beat frequency is analyzed. The mode energy coupling can be adjusted by controlling the filter. When the pump power exceeds 10 mW, bidirectional single-mode oscillations can be achieved, and the beat frequency can be switched from 50 kHz to 1.5 MHz by filter control. Finally, a linear frequency-rotation response curve of the gyroscope with the initial beat frequency set at 70 kHz is obtained..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 406001 (2011)
Red Shift of Photoluminescence Spectrum of CdSe/ZnS-Quantum-Dot Doped Fiber
Cheng Cheng, Lin Yanguo, and Yan Jinhua
CdSe/ZnS-quantum-dot doped fibers (QDF) are prepared. By measuring the photoluminescence (PL) spectra of the QDFs with various doping concentrations and fiber lengths, the red shift of the PL peak wavelength of the QDFs is observed, which is dependent on the doping concentration and the fiber length. The red shift as aCdSe/ZnS-quantum-dot doped fibers (QDF) are prepared. By measuring the photoluminescence (PL) spectra of the QDFs with various doping concentrations and fiber lengths, the red shift of the PL peak wavelength of the QDFs is observed, which is dependent on the doping concentration and the fiber length. The red shift as a function of fiber length in four fiber-core materials (toluene, ultraviolet curable adhesive, hexane and decane) is determined. Although the increase/decrease rate of the red shift depends on the core material and the doping concentration, the maximum red shift even approaches to an identical saturation value (20 nm), which is correlated with the full-width at half-maximum(FWHM) of the first absorption peak of the QD..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 406002 (2011)
Fabrication of Bi-Doped Silica Fibers with Near Infrared Broadband Emission
Wu Jindong, Chen Danping, Lu Weimin, Zhang Liyong, Wu Xingkun, and Qiu Jianrong
The modified chemical vapor deposition (MCVD) and solution-doping method is applied to the fabrication of Bi-doped silica optical fiber preforms. Bi-doped SiO2-Al2O3-GeO2 fibers with near-infrared broadband emission are realized. The characteristic spectra of preforms with different Ge-codoped concentrations fabricatedThe modified chemical vapor deposition (MCVD) and solution-doping method is applied to the fabrication of Bi-doped silica optical fiber preforms. Bi-doped SiO2-Al2O3-GeO2 fibers with near-infrared broadband emission are realized. The characteristic spectra of preforms with different Ge-codoped concentrations fabricated under various oxygen fluxes are experimentally investigated. The luminescence spectra from slices of fabricated preforms show an emission at 1146 nm with full width at half maximum (FWHM) of 204 nm when the preform is excited at 532 nm, and an emission at 1281 nm with FWHM of 250 nm when the preform is excited at 808 nm, respectively. The luminescence spectra of corresponding fibers show an emission at 1265 nm with FWHM of 280 nm when the preform is excited at 808 nm, and an emission at 1125 nm with the broadest FWHM of 460 nm when the preform is excited at 976 nm, respectively. The differences in emission between preform and fiber can be manipulated through controlling fabrication process of preform, so that the Bi-doped fiber with a suitable fluorescence and laser performance may be obtained..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 406003 (2011)
Theoretical Model and Design of Single-End Etched Fiber Bragg Grating in Low Refractive-Index Area
Luo Binbin, Zhao Mingfu, Zhou Xiaojun, Huang Deyi, and Cao Xuemei
The theoretical model of single-end etched fiber Bragg grating (FBG) for simultaneous measurements of surrounding refractive index (SRI) and temperature in the low refractive-index area (from about 1.333 to 1.360) is researched, the effects of the structural parameters on the SRI sensitivity and linearity are analyzed The theoretical model of single-end etched fiber Bragg grating (FBG) for simultaneous measurements of surrounding refractive index (SRI) and temperature in the low refractive-index area (from about 1.333 to 1.360) is researched, the effects of the structural parameters on the SRI sensitivity and linearity are analyzed in detail, and the corresponding methodology of linear approximation and error analysis is established. Simulated results show that the SRI sensitivity can be increased by reducing the diameter of the etched region or selecting the FBG with a relative bigger grating pitch for the fabrication of the sensor, however, these will cause not only the decline in the linearity but also the rise in theoretical error of the SRI sensitivity of the sensor. Based on the theoretical analysis, a single-end etched FBG is designed and fabricated for the corresponding experiments, the results of which are in accord with the simulated ones..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 406004 (2011)
Highly Sensitive Fiber-Optic Vibration Sensor Based on Frequency-Locking of a FBG Fabry-Perot Cavity
Zhang Le, Wu Bo, Ye Wen, and Shen Yonghang
A highly sensitive fiber-optic vibration sensor is developed based on the Pound-Drever-Hall (PDH) frequency locking scheme of a fiber Bragg grating (FBG) Fabry-Perot (F-P) cavity. It measures the vibration signal by the error signal transferred and amplified from the phase change of the F-P cavity. The sensor system exA highly sensitive fiber-optic vibration sensor is developed based on the Pound-Drever-Hall (PDH) frequency locking scheme of a fiber Bragg grating (FBG) Fabry-Perot (F-P) cavity. It measures the vibration signal by the error signal transferred and amplified from the phase change of the F-P cavity. The sensor system exhibits experimentally a nice sensing capability to the vibration signals within a frequency range from 1 to 5 kHz and it can obtain a more than 50dB signal to noise ratio. The analysis of the sensor, taking into account the parameters of elements used in the system and many environment factors, shows that it may reach a resolution as high as 11.7×10-12 strain/Hz, which is much better than those of the traditional fiber sensing systems..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 406006 (2011)
Image Processing
Effect of Aperture Distribution on Wavefront Recovery of Lateral Shearing Interferometer
Peng Aihua, Ye Hongwei, and Li Xinyang
The traditional least squares method(LSM) is improved by introducing the second derivative of the detected wave-front. Both the shearing data along one direction and two orthogonal directions are analysed using the improved LSM. And the spatial distribution of the wave-front recovered by the proposed method is comparedThe traditional least squares method(LSM) is improved by introducing the second derivative of the detected wave-front. Both the shearing data along one direction and two orthogonal directions are analysed using the improved LSM. And the spatial distribution of the wave-front recovered by the proposed method is compared with that of recovered by the gridding method and the integration method. The frequency response and the aperture spatial distribution characters of the wavefront recovery of lateral shearing interferometer are also analysed respectively to the annualar aperture and the combined one using the two orthogonal latering shearing data. The simulation results show the wave-front confined by any aperture could be recovered from two orthogonal lateral shearing data using the proposed algorithm..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 401002 (2011)
A New Computational Model for Performance of Airlight Rejection Utilizing Polarization Filtering
Feng Bin, Shi Zelin, Ai Rui, and Zhou Quanyun
There are no appropriate performance characteristic parameters and computational models to quantitatively compute and predict the performance of airlight rejection utilizing polarization filtering under different conditions. Therefore, a computational model for performance of airlight rejection utilizing polarization fThere are no appropriate performance characteristic parameters and computational models to quantitatively compute and predict the performance of airlight rejection utilizing polarization filtering under different conditions. Therefore, a computational model for performance of airlight rejection utilizing polarization filtering is presented. This model defines the airlight rejection ratio (ARR), integrates a model for skylight relative spectral radiant power, a solar spectral model for direct irradiance on horizontal planes, an object reflection characteristic, and other factors, and gives the ARR calculation formula whose inputs contain a sun position, an optical axis direction of a camera, atmospheric visibility, object spectral reflectance, and other parameters. Simulation and experiment of this model indicate that in sunny weather and slight haze weather, the influence respectively resulting from changes of the angular distance between the observation direction and the direction of sunlight, atmospheric visibility, and object types on the ARR gradually weakens; the change of angular distance between the observation direction and the direction of sunlight intensively affects the ARR; polarization filtering achieves similar effect of airlight rejection for most objects; the larger the ARR index is, the more effectively the image contrast is improved..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 401003 (2011)
Instrumentation, Measurement and Metrology
Research of phase demodulation technique based on S-Transform
Jiang Mohua, Chen Wenjing, and Zheng Zhiping
S-transform is one of the time-frequency analysis techniques, which combines the advantage of windowed Fourier transforma and wavelet transform. Compared with the windowed Fourier transform, S-transform has the perfect time-frequency resolution because its window size is adjusted by the variation of the frequency. CompS-transform is one of the time-frequency analysis techniques, which combines the advantage of windowed Fourier transforma and wavelet transform. Compared with the windowed Fourier transform, S-transform has the perfect time-frequency resolution because its window size is adjusted by the variation of the frequency. Compared with the wavelet transform, the frequency concept of S-transform is clear because it relates to Fourier frequency of the signal. The complete Fourier spectrum can be constituted by superimposing S-transform coefficients along the direction of space/time, while the wavelet transform just calculates the similitude between the local fringe and the stretched wavelet function instead of obtaining the frequency distribution. The paper focuses on the application of S-transform in three dimensional optical measurement based on the structured light projection, and S-transform profilometry (STP) based on the filtering way is studied. The "ridge" theory of S-transforma profilometry is completed. A strict expression of the S-transform of the deformed fringe pattern is given. The modulation map can be used to guide phase unwrapping algorithm, the application of which to S-transform profilometry is studied. We also discuss the effect of one-dimensional generalized S-transform on the fringe processing..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 412001 (2011)
Theoretical Analysis of Scanning and Identifying Cat-Eye Target with Coherently Combined Array Gaussian Beams
Zhao Yanzhong, Sun Huayan, Zheng Yonghui, and Zhang Xi
A new identification method of cat-eye target from diffusion reflective background by scanning the coherently combined array Gaussian beams is proposed. The mathematical model of coherent combination of array Gaussian beams is established．By using Collins diffraction integral formula and method of expanding the aperturA new identification method of cat-eye target from diffusion reflective background by scanning the coherently combined array Gaussian beams is proposed. The mathematical model of coherent combination of array Gaussian beams is established．By using Collins diffraction integral formula and method of expanding the aperture function into a finite sum of complex Gaussian functions, approximate analytical formulas for coherently combined array Gaussian beams passing through a cat-eye target and a Lambert diffusion reflective target are derived, respectively. Through numerical calculation, effects of array number and target size on the characteristics of the time distribution of the reflected light are studied. It is found that there is no periodic charasteristics in the time distribution of the Lambert diffusion reflective light, and the time distribution width increases along with the increase of the target size. The periodic characteristics of the time distribution of the cat-eye reflected light are similar to those of the y-axis distribution at the position of the target, and the lost frequency charasteristics increase along with the increase of the aperture size of the cat-eye target. So the cat-eye target can be identified from complicated diffusion reflective background easily and quickly, and the size of the diffusion reflective target or the cat-eye target can be estimated..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 412002 (2011)
3D Profile Measurement for Micro-Optical Component by Using Digital Holographic Microscopy
Wang Yunxin, Wang Dayong, Zhao Jie, Li Yan, and Wan Yuhong
Digital holographic microscopy (DHM) is proposed for the three-dimensional (3D) profile measurement of the micro-optical components, which is characterized by its non-invasion, non-contact, high-speed, and full-wave field scheme. Firstly, the configuration of lensless Fourier-transform DHM is designed and built. The coDigital holographic microscopy (DHM) is proposed for the three-dimensional (3D) profile measurement of the micro-optical components, which is characterized by its non-invasion, non-contact, high-speed, and full-wave field scheme. Firstly, the configuration of lensless Fourier-transform DHM is designed and built. The complex amplitude of the full-wave field is reconstructed by a single inverse fast Fourier transform only. The phase aberration is corrected by the two-step phase subtraction method, and the unwrapped phase information is extracted by using the least-squares phase-unwrapping algorithm. Then the profile information of the sample can be obtained. In the experiments, the profile of the micro-lens arrays is measured by the proposed configuration, and the results show that the caliber and relief depth are 1.595 mm and 2.424 μm respectively. These are in good agreement with the results given by the white-light interferometer. It demonstrates that the lensless Fourier-transform DHM is feasible and effective for the 3D profile measurement of the micro-optical components..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 412003 (2011)
Monitoring and Compensation of Large-Size Flat-Top Laser Beam
Zhao Tianzhuo, Fan Zhongwei, Yu Jin, Ma Tunfeng, Liu Yang, Zhang Xue, and Yan Ying
A monitoring and compensation system which is built for an amplifier that can generate flat-top laser beam is described. The amplifier uses a multi-level amplification structure. It can output 5 J energy of a single pulse, and the spot size of the flat-top laser beam is 50 mm×50 mm. The liquid-crystal valve in theA monitoring and compensation system which is built for an amplifier that can generate flat-top laser beam is described. The amplifier uses a multi-level amplification structure. It can output 5 J energy of a single pulse, and the spot size of the flat-top laser beam is 50 mm×50 mm. The liquid-crystal valve in the amplifier can modulate energy distribution of the output spot effectively. The monitoring system is combined with the spatial filter in the amplifier, and by the theory of Fourier-image transfer, it can image energy distribution of the liquid-crystal valve on the monitoring CCD. The compensation system effectively improves the quality of the output laser beam by feeding back the output spot of the amplifier on the liquid-crystal valve. Experimental result shows that energy distribution of the shaped beam is more uniform, and the near-field modulation of the flat-top laser beam generated by the amplifier is 1.64, the softening factor is 0.053. The beam-quality control and improvement are well realized by the monitoring and compensation structure..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 4, 412004 (2011)
Low-Frequency Vibration Measurement Based on Spatiotemporal Analysis of Shadow Moiré
Shi Hongjian, Zhu Feipeng, and He Xiaoyuan
A method for vibration measurement of an object based on spatiotemporal analysis of shadow moiré fringes is discussed. In this method, a sinusoidal grating is closed to a vibrating object. The moiré fringes patterns generated by the interference of grating lines and shadow lines are captured by a high-speed cA method for vibration measurement of an object based on spatiotemporal analysis of shadow moiré fringes is discussed. In this method, a sinusoidal grating is closed to a vibrating object. The moiré fringes patterns generated by the interference of grating lines and shadow lines are captured by a high-speed camera. The joint spatial and temporal information of the fringe sequences is processed by the 3D Fourier transform simultaneously rather than separately. A 3D space-time phase distribution can be obtained from the filtered spatiotemporal spectra and 3D inverse Fourier transform. From the phase values, the surface profile and displacement of the object at different time can be retrieved. The measurement experiment of a vibrating cantilever beam demonstrated the validity of this method. The results show that shadow moiré with spatiotemporal analysis can be applied to dynamic measurement..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 412005 (2011)
Surface Roughness Measurement Based on Dichromatic Digital Speckle Correlation
Liu Hengbiao, Zhou Yajie, and Wang Changling
Based on the spectral-speckle correlation method with ensemble average, dichromatic digital speckle correlation method is introduced to measure the surface roughness. The properties of dichromatic speckle spatial correlation parameter are investigated through simulated speckle fields. And the location relation of samplBased on the spectral-speckle correlation method with ensemble average, dichromatic digital speckle correlation method is introduced to measure the surface roughness. The properties of dichromatic speckle spatial correlation parameter are investigated through simulated speckle fields. And the location relation of sample and target areas is also studied. Window size influence in digital image process on peak value of spatial correlation is experimentally discussed. The surface roughness of blasted-shot and grinding specimen is measured. It is shown that dichromatic speckle spatial correlation parameter can describe surface roughness effectively. The new method has the virtue of fast image acquisition and good stability..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 412006 (2011)
Improvements of Surface Profile Measuring Device for Wolter Type-I Mirror
Cui Tiangang, Zhang Hongji, Ma Wensheng, and Chen Bo
A surface profile measuring device, based on the principle of long trace profiler, is designed and established to measure the surface profile of Wolter type-I mirror. In order to obtain higher surface profile measuring accuracy, two particular improvements are made to the surface profile measuring device. The nonlinearA surface profile measuring device, based on the principle of long trace profiler, is designed and established to measure the surface profile of Wolter type-I mirror. In order to obtain higher surface profile measuring accuracy, two particular improvements are made to the surface profile measuring device. The nonlinear error and the motion error of the translation slide can be eliminated by using a penta prism, which possesses an optical property all its own. The ideal measuring accuracy of the surface profile measuring device is improved by using position sensitive detector instead of CCD detector. The calibration and sample measurement experiments are done and the experimental data are compared with the old data. The result shows that the new measuring device can achieve an accuracy of 1.7 μrad for slope root-mean-square error and 56 nm for peak to valley height error. Its measuring accuracy has been significantly improved. This can meet further requirements of precision fabrication for Wolter type-I mirror..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 412007 (2011)
Eliminating Influence of Grating Encoder′s Eccentricity and Vibration to Moiré Fringes Signal by Four Reading Heads
Zhu Fan, Wu Yiming, and Liu Changchun
Presently, grating encoder is an important way to accurately measure angle, however, the eccentric inaccuracy of assembling adjusting and the vibration of rotating shaft influence grating encoder′s measuring accuracy and then confine the application range of grating encoder. A new method to eliminate the influence of ePresently, grating encoder is an important way to accurately measure angle, however, the eccentric inaccuracy of assembling adjusting and the vibration of rotating shaft influence grating encoder′s measuring accuracy and then confine the application range of grating encoder. A new method to eliminate the influence of eccentricity and vibration with four reading heads is proposed and the theoretical derivation and simulation results are given out. The conclusion hints that the method which gets moiré fringes signal by four reading heads well-distributed along the circumference of grating is more effective in improving the measuring accuracy than the one that uses double reading heads. Consequently, the new method decreases the requirements of assembling adjusting. The direction and magnitude also can be solved by four reading heads, so the influence of rotating shaft can be eliminated. All the results are useful to deeper research..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 412008 (2011)
An Algorithm for Interferometric Image Processing of Interferometric Particle Imaging
Lü Qieni, Ge Baozhen, Chen Yiliang, and Zhang Yimo
A method of extracting the number of fringes/fringe spacing of interferogram based on wavelet matched filtering and Fourier transform technique is proposed. The edge images of the interference pattern of particle and the particle mask image are detected respectively by Mexican Hat wavelet and the center of particle canA method of extracting the number of fringes/fringe spacing of interferogram based on wavelet matched filtering and Fourier transform technique is proposed. The edge images of the interference pattern of particle and the particle mask image are detected respectively by Mexican Hat wavelet and the center of particle can be extracted through the 2D correlation operation for the two edge images obtained. Then the interference pattern of each particle can be achieved using the center coordinate, shape and size of the particle image. The fringe counting/fringe spacing of the interferogram of a particle is obtained by Fourier transform and the modified Rife algorithm, and sub-pixel accuracy of the extracted frequency is acquired. The performance of the method is demonstrated using simulation and experimental measurements. The simulation results are that the recognition ratio is more than 90% and the extracted frequency error is less than 0.0185% for the overlap coefficient γ<11.62%. The measurement uncertainty is ±0.41 μm and the absolute error is 1.31 μm for the standard particles of diameter of 51.1 μm. The research results show that the algorithm presented in this paper is feasible..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 412009 (2011)
Fourier Conjugate Correction Spectral Reconstruction for Fourier-Transform Spectrometer
Li Suning, Zhu Rihong, Gao Zhishan, and Li Jianxin
The spectral reconstruction theory of Fourier-transform imaging spectrometer is based on the Fourier-transform relationship between the spectrum of the source and the interferogram so that the spectral reconstruction can be simply achieved by using Fourier transform or Fourier cosine transform. However, the traditionalThe spectral reconstruction theory of Fourier-transform imaging spectrometer is based on the Fourier-transform relationship between the spectrum of the source and the interferogram so that the spectral reconstruction can be simply achieved by using Fourier transform or Fourier cosine transform. However, the traditional Fourier transform solution is carried out in the complex-number field and the result is also a complex-number sequence. To acquire the real-number reconstructed spectrum, people usually use the real part or the absolute magnitude of the transformation result as the reconstructed spectrum, which will introduce in an extra-phase to the spectrum and lead to inaccuracy of reconstructed spectral intensity. Although reseachers use Fourier cosine transform to avoid the extra-phase problem effectively, this solution has a boundary condition problem which cannot be avoid and may also lead to inaccuracy of reconstructed spectral intensity. To solve the problem, on the base of the analysis of traditional reconstruction solutions, an improved spectral reconstruction solution based on Fourier conjugate correction (FCC) for Fourier-transform spectrometer is developed and discussed. Firstly the conjugated symmetrical form of the interferogram sequence is created by the use of the original interferogram captured, and then the conjugated symmetrical spectrum and the correction element can be acquired by carrying out Fourier transform to the sequence. By using the conjugated symmetrical spectrum and the correction element, the real-number spectrum sequence can be calculated. By carrying out both the simulation and the experiment using helium lamp, it can be concluded that the FCC solution can avoid either the extra-phase problem caused by discrete Fourier transform (DFT) solution or the boundary condition caused by discrete Fourier cosine transform (DCT) solution effectively and improve the reconstructed spectral intensity accuracy..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 412010 (2011)
Carrier Removal Method in Fringe Projection Profilometry Using Zernike Polynomials
Wu Zhiyun, and Zhang Qican
In three-dimentional (3D) profilometry based on fringe projection, projected fringe patterns will introduce carrier phases into the overall phase distribution. In an actual imaging system, optical aberration will result in nonlinear carrier, so the nonlinear carrier must be removed accurately to get the phase distributIn three-dimentional (3D) profilometry based on fringe projection, projected fringe patterns will introduce carrier phases into the overall phase distribution. In an actual imaging system, optical aberration will result in nonlinear carrier, so the nonlinear carrier must be removed accurately to get the phase distribution modulated by the object. A new carrier removal method using Zernike polynomials fitting is proposed. The carrier phases can be obtained by Zernike polynomials fitting using data points on reference area. By subtracting the carrier phases from the overall phase distribution, the object height-related phases can be obtained. Simulation experiments are performed to evaluate the performance of the method for two deformed fringe patterns with and without image aberration. The experimental results show that the method can effectively remove the carrier, and reduce the reconstruction error. And this method has simple algorithm, needs only one image and can be used in the applications which require least time consumption..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 4, 412011 (2011)
Three-Dimensional Electronic Speckle Pattern Interferometry with Carrier Modulation by Using Large-Shearing Block Prism
Sun Ping, Fan Xiangju, and Wang Xinghai
A technique with carrier modulation for three-dimensional displacement measurement by using electronic speckle pattern interferometry (ESPI) is presented. Firstly, a new block prism, named large-shearing block prism, is designed. A large-shearing electronic speckle pattern interferometer can be constituted when large-sA technique with carrier modulation for three-dimensional displacement measurement by using electronic speckle pattern interferometry (ESPI) is presented. Firstly, a new block prism, named large-shearing block prism, is designed. A large-shearing electronic speckle pattern interferometer can be constituted when large-shearing block prism is used. Secondly, the test object and reference object are illuminated separately by three lasers which are fixed on horizontal and perpendicular position. A new three-dimensional (3D) ESPI system is constructed by three lasers, a large-shearing block prism and a CCD camera as well as a reference object. The carrier fringes in three interference fields can be introduced by rotating the reference object with a small angle. Interference speckle patterns before and after deformation, and interference speckle patterns after rotation of reference surface are collected when three lasers are used respectively. After the images are subtracted, three carrier fringe patterns and three modulated carrier fringe patterns under different illumination are obtained. Finally, three phase maps can be demodulated by using Fourier transform. Further phase calculation is needed to separate three displacement components. A typical three-point-bending-beam experiment is completed by the 3D system presented. Experimental results are offered, which show that three displacement components can be determined effectively. The 3D system has simple optical setup and has an easy way to operate, therefore it provides a new approach to three-dimensional deformation measurement..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 412012 (2011)
Lasers and Laser Optics
Side-Pumped NdYAG Pulsed Laser with Conduction Cooling
Xiao Chongli, Wan Chunming, and Ling Ming
A new pumping structure about laser diode (LD) side-pumped NdYAG Q-switched laser without water cooling was reserched. Side-pumping was done with three LD centimeter strips made by 12 cm bar. NdYAG crystal rods were smoothly fitted to copper stucking net with cooling units, which mounted on the heat sink copper ring. AA new pumping structure about laser diode (LD) side-pumped NdYAG Q-switched laser without water cooling was reserched. Side-pumping was done with three LD centimeter strips made by 12 cm bar. NdYAG crystal rods were smoothly fitted to copper stucking net with cooling units, which mounted on the heat sink copper ring. And copper ring was processed into the aluminum heat sink ring sets with outer surface of the triangle stack slot. Three long rectangular array laser diodes according to their specific design were fixed to the heat sink in order to ensure working at constant temperature without water cooling. Experiencing at the range of -20 ℃ and 40 ℃, the low-order mode laser output of 9 ns pulse width and maximum 98 mJ in 1064 nm is obtained and output energy and stability at -20 ℃ was higher than that at 40 ℃. This design can reduce the laser volume and increase the system efficiency at last..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 414001 (2011)
Analysis of Gaussian-Vortex Beam and Its Application in a Relay Mirror System
Wu Huiyun, Huang Zhihe, Wu Wuming, Xu Xiaojun, Chen Jinbao, and Zhao Yijun
A new method that decreases the power loss in uplink propagation of a relay mirror system by using a Gaussian-vortex beam source is proposed. Performance of a 30 km-altituide relay mirror system that uses a Gaussian beam source is calculated. Results show that power coupling efficiency of uplink propagation in the relaA new method that decreases the power loss in uplink propagation of a relay mirror system by using a Gaussian-vortex beam source is proposed. Performance of a 30 km-altituide relay mirror system that uses a Gaussian beam source is calculated. Results show that power coupling efficiency of uplink propagation in the relay mirror system is 76.48％, beam blocked by secondary mirror of the receiving telescope causes the main power loss and power loss proportion caused by beam blocking is 22.85％. Relation between shape and aperture of the dark area generated at the center of a Gaussian-vortex beam with parameters of the beam are analyzed in detail. Results show that shape of the hollow area is determined by amount of phase vortex of the beam, the hollow area is circular only when amount of phase vortex is times of 2π, aperture of the dark hollow increases with the increase of amount of phase vortex and propagation distance, respectively. Performance of a 30 km-altituide relay mirror system that uses a Gaussian-vortex beam source is calculated. Results show that power coupling efficiency of uplink propagation in the relay mirror system is 97.25％, and power loss in uplink propagation is significantly decreased..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 414002 (2011)
A Widely Tunable Mid-Infrared Difference Frequency Generation Laser and Its Detection of Atmospheric Water
Wang Liusan, Cao Zhensong, Wang Huan, Zhao Hui, Gao Wei, Yuan Yiqian, Chen Weidong, Zhang Weijun, and Gao Xiaoming
A widely tunable (5～12.5 μm) continuous wave mid-infrared laser based on difference frequency generation (DFG) in a AgGaS2 crystal with type II (e+o→e)phase matching is reported. The pump laser is a master oscillator power amplifier (MOPA) system which consists of a grating-tuned external-cavity diode laser in Littrow A widely tunable (5～12.5 μm) continuous wave mid-infrared laser based on difference frequency generation (DFG) in a AgGaS2 crystal with type II (e+o→e)phase matching is reported. The pump laser is a master oscillator power amplifier (MOPA) system which consists of a grating-tuned external-cavity diode laser in Littrow configuration and a tapered semiconductor amplifier, which is tunable from 760 to 790 nm with a maximum power of 800 mW(780 nm). The signal laser is a Tisapphire laser, which is tunable from 790 to 910 nm with a maximum power of 760 mW (806 nm). A maximum output power of 1.076 μW is obtained near 7.0 μm. Based on the difference frequency generation laser, the direct absorption spectrum of (000→010) band of water vapor near 7.0 μm in laboratory air is measured. Under the absorption optical path of 19.0 cm in open air, the concentration of water vapor in laboratory air is estimated from the recorded absorption spectrum..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 414003 (2011)
Machine Vision
Large-Scale Camera Calibration with Neural Network
Tian Zhen, Zhang Qi, Xiong Jiulong, and Wang Guochao
Current researches on camera calibration using neural network can only keep precision within a small space, unfortunabely, there has no such a method that can solve conflict between calibration precision and speed as space extends. It is proved that there are different imaging rules along three axes (XW axis, YW axis aCurrent researches on camera calibration using neural network can only keep precision within a small space, unfortunabely, there has no such a method that can solve conflict between calibration precision and speed as space extends. It is proved that there are different imaging rules along three axes (XW axis, YW axis and ZW axis) in the world coordinate system, and a brand new parallel calibration method is created to calibrate camera along these three directions respectively, namely parallel calibration. A new normalization method is proposed and better calibration precisions are gained along both XW axis and YW axis. There comes conclusion that calibration along ZW axis is critical to the whole large-scale calibration since standard deviation of reconstruction along ZW axis is much higher than those along XW axis and YW axis. Expersmental results show that the new normalization method extends calibration scale while keeping both calibration precision and speed..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 415001 (2011)
Calibration for Gaze Tracking System Based on Stereo Cameras and Plane Mirror
Zhang Qiong, Wang Zhiliang, Chi Jiannan, and Shi Xuefei
In stereo cameras gaze tracking system, cameras can not directly measure the object spatial coordinates outside field of view outside. In order to solve this problem, a system calibration method based on plane mirror is proposed. First, to calibrate stereo cameras to determine the relation between two cameras, a unifieIn stereo cameras gaze tracking system, cameras can not directly measure the object spatial coordinates outside field of view outside. In order to solve this problem, a system calibration method based on plane mirror is proposed. First, to calibrate stereo cameras to determine the relation between two cameras, a unified world coordinate system is created. Secondly, according to the plane mirror imaging principle, the spatial coordinates of the monitor screen and light source image are decided. The spatial location of light source and screen is determined. The experimental results show that the method has high precision. When the user is away from the screen 500~600 mm, the average accuracy of gazing point can reach 1°, and meet the needs of most gaze tracking applications..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 415002 (2011)
Materials
Design Methods of Fractal Frequency Selective Surface Based on Quasi-Optical Waveband
Wang Shanshan, Gao Jinsong, Feng Xiaoguo, Liang Fengchao, and Zhao Jingli
Frequency selective surface (FSS) is mainly used as passive filters to separate optical Gaussian beam in quasi-optical system. The multiband FSS on single screen can be designed using self-similar fractal elements as periodic cells. Take cross element for example we can obtain second-order cross fractal element by recuFrequency selective surface (FSS) is mainly used as passive filters to separate optical Gaussian beam in quasi-optical system. The multiband FSS on single screen can be designed using self-similar fractal elements as periodic cells. Take cross element for example we can obtain second-order cross fractal element by recursive algorithm. The method of moments is employed to characterize the transmission properties of fractal band-pass FSS combining with Floquet′s periodic theory and boundary conditions. The transmissivity of multiband FSS with resonant frequencies of 58 GHz and 145 GHz are all above 95%. After analyzing the influence of changing the structural parameters of fractal FSS on its transmission characteristic, it is known that the first resonant frequency f1 is decided by the arm length L1 of the original element and the second resonant frequency f2 is sensitive to the arm length L2 of the iterative element, the stability of the transmission characteristics of f1 is better than f2. We examine the stability of the fractal FSS frequency response when changing the incident angle and polarization of the electromagnetic wave..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 416001 (2011)
Growth and Spectroscopic Properties of Nd3+:Ca9Y(VO4)7 Crystal
Lin Zhoubin, Zhang Lizhen, and Wang Guofu
A Nd3+-doped Ca9Y(VO4)7 crystal with high optical quality and dimension of φ30 mm×35 mm has been grown by the Czochralski method. The effective segregation coefficient of Nd3+ ion is measured as 0.75. The parameter of second-order nonlinear optical coefficient of the powder is 1.5 times as large as that of KDP cryA Nd3+-doped Ca9Y(VO4)7 crystal with high optical quality and dimension of φ30 mm×35 mm has been grown by the Czochralski method. The effective segregation coefficient of Nd3+ ion is measured as 0.75. The parameter of second-order nonlinear optical coefficient of the powder is 1.5 times as large as that of KDP crystal. Its Vickers hardness is 362. The spectral properties of Nd3+Ca9Y(VO4)7 crystal have been investigated that the absorption cross section is 1.50×10-19 cm2 with full width half maximum (FWHM) of 13 nm at 809 nm, which fits to be pumped by GaAlAs laser diode. The emission cross section is 1.35×10-20 cm2 and the fluorescence lifetime is 103 μs at the highest emission peak of 1069 nm. The results show that the Nd3+Ca9Y(VO4)7 crystal is a new self-frequency-doubling crystal..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 416002 (2011)
Energy of Magnetopolaron in Wurtzite GaN/Al0.3Ga0.7N Quantum Well
Zhao Fengqi, Sachuronggui, and Wurentuya
The energy levels of magnetopolaron in the wurtzite GaN/Al0.3Ga0.7N quantum well structure are studied by using Lee-Low-Pines (LLP) variational method. The ground state energy in wurtzite GaN/Al0.3Ga0.7N quantum well structure is calculated as a function of well width L and external magnetic field B. The transition eneThe energy levels of magnetopolaron in the wurtzite GaN/Al0.3Ga0.7N quantum well structure are studied by using Lee-Low-Pines (LLP) variational method. The ground state energy in wurtzite GaN/Al0.3Ga0.7N quantum well structure is calculated as a function of well width L and external magnetic field B. The transition energy and cyclotron frequency of magnetopolarons are calculated as functions of magnetic field B. The anisotropy of the optical phonon modes and the interaction of electron-optical phonon in wurtzite GaN/Al0.3Ga0.7N quantum well are considered in numerical calculation. For the qualitative analysis and comparison, the energy and cyclotron frequency of magnetopolaron in zinc blende GaN/Al0.3Ga0.7N quantum well are calculated..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 416003 (2011)
Surface Plasmon Polaritons of Magnetically Tunable Metamaterials
Zhang Huifang, Zhao Yujing, Ren Haihong, and Wang Yan
For the p and s polarizations, the surface plasmon polaritons (SPP) of magnetically tunable left-handed materials (LHM) and regular materials are investigated. The dispersion relations and characteristic lengths of SPP, including SPP wavelength, propagation distance of SPP and penetration depths of SPP in two mediums, For the p and s polarizations, the surface plasmon polaritons (SPP) of magnetically tunable left-handed materials (LHM) and regular materials are investigated. The dispersion relations and characteristic lengths of SPP, including SPP wavelength, propagation distance of SPP and penetration depths of SPP in two mediums, are discussed in detail in different magnetic fields. It is shown that the properties of SPP can be controlled by the adjustment of effective magnetic permeability of metamaterials which is changed by changing the magnetic-field intensity. And the characteristic curves of SPP move to the region of short wavelength when the additional magnetic-field intensity increases..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 416004 (2011)
Theoretical Studies on UV-Vis Absorption Spectra and the Third-Order Nonlinear Optical Coefficients of Cyclometalated Platinum Complexes with Long Chain β-Diketonate Ancillary Ligands
Yuan Bo, Wei Hang, Yang Fan, Li Quan, Luo Kaijun, and Zhao Keqing
The time-dependent density functional theory (TD-DFT) B3LYP method is used to investigate the UV-vis absorption spectra of six cyclometalated platinum complexes with long-chain β-diketonate ancillary ligands. The results indicate that the electronic transition from the ground state to the first excited state is ligand-The time-dependent density functional theory (TD-DFT) B3LYP method is used to investigate the UV-vis absorption spectra of six cyclometalated platinum complexes with long-chain β-diketonate ancillary ligands. The results indicate that the electronic transition from the ground state to the first excited state is ligand-to-ligand charge transfer (LLCT) and metal-to-ligand charge transfer (MLCT) transition. The maximum absorption wavelength of the six compounds is around in the range of 402~405 nm due to the near ultraviolet region. The finite field (FF) method is used to investigate the third-order nonlinear optical properties of the six complexes. The results show that these complexes display good third-order nonlinear optical coefficients (in 105 order of magnitude). From one to fourteen carbon atoms range, increasing β-diketonate carbon chain length and introducing methyl respectively in the ligands benzene or pyridine are both conducive to increase the third-order nonlinear optical properties..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 416005 (2011)
Microscopy
Simulation of Coherent Diffraction Imaging Based on Scanning Transimission X-Ray Microscopy of Shanghai Synchrotron Radiation Facility
Tan Xingxing, Liu Haigang, Guo Zhi, Wu Yanqing, Xu Zijian, Wang Yong, and Tai Renzhong
Scanning transmission X-ray microscopy (STXM) is a recently developed spectroscopic microscopy based on the third generation synchrotron radiation facilities. Shanghai Synchrotron Radiation Facility (SSRF) has achieved STXM method, and the energy spans from 250 to 2000eV which covers most of the important elements′ absScanning transmission X-ray microscopy (STXM) is a recently developed spectroscopic microscopy based on the third generation synchrotron radiation facilities. Shanghai Synchrotron Radiation Facility (SSRF) has achieved STXM method, and the energy spans from 250 to 2000eV which covers most of the important elements′ absorption edge. A new experimental method: by fully using the STXM equipment to develop scanning X-ray diffractive technology, not only can improve the spatial resolution, but also can be easy to implement. Considering the specialty of SSRF, the condition of coherence of SSRF for scanning X-ray diffractive technology and experimental condition for the image resolution of reconstruction are discussed. Finally, the method using specific parameters is simulated. Simulation shows that using this technology can efficiently improve the spatial resolution based on specific experimental conditions of specific specimen..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 418001 (2011)
Design of Evaluation Index for Auto-Focusing Function and Optimal Function Selection
Zhai Yongping, Zhou Dongxiang, Liu Yunhui, Liu Shun, and Peng Keju
Selection of the optimal focusing function from a given set of focusing functions is an important issue in image-based auto-focusinging that is usually used in automatic image acquisition systems, such as automatic microscopes, vision-based micro-operating robots, etc. However, there is no quantitative index available Selection of the optimal focusing function from a given set of focusing functions is an important issue in image-based auto-focusinging that is usually used in automatic image acquisition systems, such as automatic microscopes, vision-based micro-operating robots, etc. However, there is no quantitative index available for evaluating the performance of the focusing functions. Six quantitative evaluation index, including the width of steep part of focusing curve, the ratio of sharpness, the steepness, the variance of flat part of focusing curve, the factor of local extreme and the sensitivity are designed. These index can not only been used in the selection of optimal focusing function, but also provide theoretical basis for the design of new focusing function. Then, twelve typical focusing functions are evaluated based on the quantitative evaluation index. Results show that the variance function is the optimal focusing function in coarse auto-focusing, while the Brenner function is the optimal focusing function in fine auto-focusing..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 418002 (2011)
Nonlinear Optics
Soliton-Effect Pulse Compression in a Dispersion-Decreasing Fiber-Based Mach-Zehnder Interferometer
Cao Wenhua, Xu Ping, and Liu Songhao
Soliton-effect optical pulse compression in a dispersion-decreasing fiber (DDF) based on Mach-Zehnder interferometer (MZI) is studied numerically. The scheme utilizes both the higher-order soliton compression and the nonlinear switching effects within the MZI. Numerical results show that the scheme cannot only permit mSoliton-effect optical pulse compression in a dispersion-decreasing fiber (DDF) based on Mach-Zehnder interferometer (MZI) is studied numerically. The scheme utilizes both the higher-order soliton compression and the nonlinear switching effects within the MZI. Numerical results show that the scheme cannot only permit much more efficient pulse compression than the DDF-based adiabatic soliton compression technique, but also compress wide pulse which will be impossible with the adiabatic soliton compression technique. For a 20-ps input pulse, the compression ratio by the present scheme is as high as 76.4. Results also show that the compression is quite tolerant of small variation of initial parameters such as the arm length of the MZI, the input to output dispersion ratios of the two arms, and the peak power of the input pulse. The influence of higher-order effects such as Raman self-frequency shift and the third-order dispersion on pulse compression is also investigated..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 419001 (2011)
Optical Design and Fabrication
Large-Aperture Aspheric Surfaces Testing by Using Sinusoidal Grating Based on Ronchi Method
Guo Chunfeng, Su Xianyu, Dou Yunfu, Chen Wenjing, Lei Baiping, and Wu Fan
A method based on Ronchi test and synchronous phase detection technology is presented to measure the aspheric mirror, where the point source is located beside the axis of the surface. A liquid crystal display screen displays the vertical and horizontal sinusoidal gratings and a camera captures the deformed fringe patteA method based on Ronchi test and synchronous phase detection technology is presented to measure the aspheric mirror, where the point source is located beside the axis of the surface. A liquid crystal display screen displays the vertical and horizontal sinusoidal gratings and a camera captures the deformed fringe patterns generated by the reflection of the mirror. By four-step phase-shifting technique, the phase distributions are obtained. According to points with the same phase on the deformed fringes and grating, the transverse aberration of all tested points can be calculated, while that of the relevant ideal mirror can be worked out by geometry algorithms. Then the residual transverse aberration can be taken and thus the gradient of shape deviation can be determined. Tested mirror can be reconstructed after restoring shape deviations by integral processing. In experiment, the computer-generated fringe will bring a no-error phase shift and control the angle of two gratings to be 90°. A marked point is used to guide the phase unwrapping procedure. Computer simulations and preliminary experiment validate the feasibility of this method..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 422001 (2011)
Optical Devices
Fabrication and Optical Properties of Two-Dimensional Thue-Morse Quasicrystals
Feng Yaping, Zhou Jun, Yang Mingyang, Lucia Petti, Lin Hao, and Ding Haifang
A large-area two-dimensional Thue-Morse quasicrystal with nanometer structures is fabricated on poly-methyl methacrylate (PMMA) substrate using the technology of electron beam lithography (EBL). And the optical properties of sample are studied by the far-field diffraction experiment. In addition, according to the diffrA large-area two-dimensional Thue-Morse quasicrystal with nanometer structures is fabricated on poly-methyl methacrylate (PMMA) substrate using the technology of electron beam lithography (EBL). And the optical properties of sample are studied by the far-field diffraction experiment. In addition, according to the diffraction principle and interference theory, the Fraunhofer diffraction patterns of the Thue-Morse quasicrystal are simulated and analyzed. It is shown that the theoretical simulations are consistent with the experimental results very well..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 423001 (2011)
Quantum Optics
Study on Preparation and Characteristics of Quantum Entanglement in Double Wells Using a Spin-1/2 Approximation
Chen Jing, Guo Yanqing, and Shi Xuguang
As the foundation of quantum theory, the preparation of many-particle entangled states in macroscopic systems is one of the major goals. A spin-1/2 approximation method is proposed to study the quantum entanglement of two-component Bose-Einstein condensates (BEC) trapped in double wells. This approximation is demonstraAs the foundation of quantum theory, the preparation of many-particle entangled states in macroscopic systems is one of the major goals. A spin-1/2 approximation method is proposed to study the quantum entanglement of two-component Bose-Einstein condensates (BEC) trapped in double wells. This approximation is demonstrated to be valid under the stationary tunneling condition and for odd particle numbers of each component. The evolutionary process of system states are both analyzed under effective Hamiltonian and whole Hamiltonian. Strong and long time sustained entanglement with respect to tunneling rate and the exact time can be achieved. It is discussed that the effect of the system characteristics on the entangle degree. A multibody problem which is difficult even for single component BEC can be transformed to a bipartite two-state one by this theory, similarly, the entanglement measureent can be achived more effectively..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 427001 (2011)
Entanglement Characteristics of Two Entangled Atoms in Classical Driven Tavis-Cummings Model
Han Mei, Zhang Yingjie, and Xia Yunjie
The dynamical behaviors of two entangled two-level atoms, which interact with a single-mode cavity field and driven by the classical field are investigated. The Tavis-Cummings model in which the dipole-dipole interaction between two atoms and the classical driven strength exists simultaneously is studied. By means of nThe dynamical behaviors of two entangled two-level atoms, which interact with a single-mode cavity field and driven by the classical field are investigated. The Tavis-Cummings model in which the dipole-dipole interaction between two atoms and the classical driven strength exists simultaneously is studied. By means of numerical calculations, we analyze the effect of the classical field driven strength, dipole-dipole interaction between two atoms and the detuning between atoms and cavity field on the entanglement dynamical properties of two atoms. Meanwhile, we discuss the optimal region of dipole-dipole interaction between two atoms and the classical field driven strength in the case of resonance and offresonance between atoms and cavity field. The result shows that when we choose the appropriate conditions, the phenomenon of entanglement sudden death can be inhibited..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 427002 (2011)
Thin Films
Fabrication and Properties of Cu-Doped NiO Electrochromic Thin Films
Zhao Lili, Su Ge, Cao Lixin, Liu Wei, Wang Jing, Dong Zheng, and Song Meiqin
Cu-doped nickel oxide (NiO) thin films are prepared by electrochemical deposition technique from N, N-dimethylformamide (DMF) solutions. Morphology, structure, optical and electrochromic properties of the Cu-doped NiO films are investigated by means of scanning electron microscope (SEM), X-ray diffraction (XRD), ultravCu-doped nickel oxide (NiO) thin films are prepared by electrochemical deposition technique from N, N-dimethylformamide (DMF) solutions. Morphology, structure, optical and electrochromic properties of the Cu-doped NiO films are investigated by means of scanning electron microscope (SEM), X-ray diffraction (XRD), ultraviolet-visible spectrophotometer (UV-vis), Fourier-transform infrared spectrometer(FTIR) and cyclic voltammetry (CV), respectively. Studies on the effects of Cu doping concentration, deposition potential and deposition time on the transmission properties of both the bleached state and colored state show that when CuNi =18, the film deposited under 3.5 V for 15 min exhibits the optimum electrochromic behavior with a max variation of transmittance (ΔTλ=560 nm) up to 78.7%. SEM images indicate the formation of nanorods. The films are formed with amorphous or short-range ordered NiO grains and a trace of face-centered cubic NixCu1-xO confirmed by XRD. Cu-doped NiO film also exhibits the fast response time as well as long cycle life..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 431001 (2011)
Active Design of Multilayer Optical Coatings Based on Sensitivity Control
Huang Yun, Wu Suyong, and Yang Kaiyong
Deposition errors of oblique incidence optical coatings have a serious degradation influence on their spectral characteristics according to practical preparation experiences. An active multilayer optical coating design method based on sensitivity control is put forward to minimize the above influence. The distribution Deposition errors of oblique incidence optical coatings have a serious degradation influence on their spectral characteristics according to practical preparation experiences. An active multilayer optical coating design method based on sensitivity control is put forward to minimize the above influence. The distribution law of deposited layers′ errors of structural parameters is thoroughly analyzed. Calculation model of multilayer optical coating′s sensitivity is analytically established. Numerical design experiments in large incident angle non-polarization antireflection coatings are operated to explore and verify the feasibility and effectiveness of sensitivity control thought in films design. And numerical results show that this optical coating design method can obtain films with good manufacture feasibility without extending much program time consumption. Additionally, this design technique can make the planning of manufacture process possible without expensive sampling and make a shortening production cycle for new coating systems. It is of obvious significance for repetitive production of high quality oblique incidence optical coatings..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 431002 (2011)
Vision, Color, and Visual Optics
Sub-Space Compensation Model for Accurate Colorimetric Characterization of Liquid Crystal Displays
Gong Rui, Xu Haisong, Zhang Xiandou, and M.Ronnier Luo
The accurate colorimetric characterization of liquid crystal displays (LCDs) has many difficulties, such as channel interaction and non-constancy of channel chromaticity. Based on the well-performed masking model, a new colorimetric characterization method, namely, sub-space compensation model (SC model) concerning theThe accurate colorimetric characterization of liquid crystal displays (LCDs) has many difficulties, such as channel interaction and non-constancy of channel chromaticity. Based on the well-performed masking model, a new colorimetric characterization method, namely, sub-space compensation model (SC model) concerning the advantages of the sub-space partition is proposed for LCDs. Firstly, the training data corresponding to different RGB subspaces should be measured, then the relationship between the prediction error of XYZ tristimulus values and the input drive data can be calculated using quadratic polynomial, so that the XYZ prediction error of masking model will be compensated. For the four tested LCDs, the experimental results show that the best mean prediction color differences of the SC model are 0.2783, 0.3199, 0.7090 and 1.2216 CIELAB unit, respectively, which verify that the prediction accuracy of SC model outperforms other conventional models, and that the new model can be applied to all kinds of LCDs..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 433001 (2011)
X-Ray Optics
Application of Capillary Focusing X-Ray Lens in Obtaining Latent Fingerprint
Sun Tianxi, Liu Zhiguo, Li Yude, Lin Xiaoyan, Luo Ping, Pan Qiuli, Yang Ke, Yuan Hao, and Ding Xunliang
The characteristic X-ray imaging technology is proposed to obtain the latent fingerprint. To obtain the latent fingeprint, the X-ray fluorescence spectrometer based on the capillary focusing X-ray lens (CFXRL) and the laboratory X-ray source is designed. The focal spot diameter of CFXRL and the gain of CFXRL are 32.2 μThe characteristic X-ray imaging technology is proposed to obtain the latent fingerprint. To obtain the latent fingeprint, the X-ray fluorescence spectrometer based on the capillary focusing X-ray lens (CFXRL) and the laboratory X-ray source is designed. The focal spot diameter of CFXRL and the gain of CFXRL are 32.2 μm and 2940 respectively. This is helpful in detecting the characteristic X-rays of the elements in latent fingerprint efficiently, with high spatial resolution. Characteristic X-ray imaging technology can judge the substance contacted by the fingerprint owner before leaving it. This is also useful in forensic sciences. It is proved that the CFXRL has potential applications in obtaining the latent fingerprint..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 4, 434001 (2011)
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