Contents
2015
Volume: 35 Issue 6
53 Article(s)
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Atmospheric Optics and Oceanic Optics
Study on the Method of Passive Multi-Mode Space-Based Atmospheric Sounding Spectrometers Nadir and Limb Matching in-Flight
Cui Chengguang, Wang Shurong, Huang Yu, and Li Bo
The passive space-borne atmospheric sounding spectrometer is a multi-mode hyper-spectral spectrometer and in a sun synchronous polar orbit. One of its main objectives is to observe the same atmospheric volume in both nadir and limb within one orbit, i.e. nadir/limb matching . In order to observe the same atmospheric voThe passive space-borne atmospheric sounding spectrometer is a multi-mode hyper-spectral spectrometer and in a sun synchronous polar orbit. One of its main objectives is to observe the same atmospheric volume in both nadir and limb within one orbit, i.e. nadir/limb matching . In order to observe the same atmospheric volume in both nadir and limb, the method and time interval ΔT of nadir/limb matching are researched. According to the operation modes of the payload, satellite orbit and Earth’s rotation, the mathematical matching model is founded to study the method of nadir/ limb matching. Through calculation of Matlab and simulation of nadir/ limb matching in Satellite Tool Kit (STK), the time interval are intended to be 429 s and 430 s respectively. At last, considering Earth’s oblateness and orbit decay, combining with the two settings of nadir and limb scanning, and uniforming detection target area of nadir and limb, the final time interval is confirmed to be 430 s..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 601001 (2015)
Modeling Calculation for Space-Based Ultravioled Clutter Radiance from Different Scenes
Xu Feifei, Hu Yong, Yin Qiu, and Yin Dayi
For the space-based ultraviolet (UV) detection system, quantitatively estimating the clutter radiance from the fluctuations of earth-atmospheric background is beneficial to effectively select the detecting channels (including middle- wavelength and spectral- range) in different scenes, and can improve the comprehensiveFor the space-based ultraviolet (UV) detection system, quantitatively estimating the clutter radiance from the fluctuations of earth-atmospheric background is beneficial to effectively select the detecting channels (including middle- wavelength and spectral- range) in different scenes, and can improve the comprehensively detecting performance for the space target. Based on the space signal transfer, the space clutter radiance models in different scenes are established in the UV window of 290~400 nm. By means of the models, the main influence factors for the space background clutter radiance are analyzed. In the level of the possible target radiation characteristics and earth-atmospheric background clutter radiance, the detecting performance of system influenced by the clutter is effectively estimated. The results show that the middle-wavelength and spectral-range of detecting system should be 300 nm and 297~306 nm for clear sky, but 299 nm and 296~303 nm respevtively for the field of cirrus clouds..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 601002 (2015)
Atomic and Molecular Physics
Effects of Non-Collimation of Gaussian Laser on Laser-Focused Cr Atom Deposition
Zhang Baowu, Yao Luyu, Chen Jun, and Wang Daodang
The uniformity of the deposited lines by laser- focusing along the substrate surface is simulated with Gaussian laser. The result shows that the optical potential formed by the Gaussian laser is different from the collimated Gaussian laser either along or perpendicular to the laser axis. This difference results in asymThe uniformity of the deposited lines by laser- focusing along the substrate surface is simulated with Gaussian laser. The result shows that the optical potential formed by the Gaussian laser is different from the collimated Gaussian laser either along or perpendicular to the laser axis. This difference results in asymmetry of atomic trajectories related to the laser standing node, and the congregation area is offset to smaller than absolute value of x0 when x0 varies from 0mm to -50mm. Consequently, all the full width at half maximum (FWHM), center peak and offsets of center of the deposited lines have the linear variations with x0, and each of them has 8nm increase, 50 units decrease and 15nm increase, respectively, when x0 varies from 0mm to -50 mm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 602001 (2015)
Comparative Research of Measuring Methods of Rubidium Atom Transverse Relaxation Time
Ding Zhichao, Yuan Jie, Li Yingying, Feng Wei, and Wang Zhiguo
In order to accurately measure the short transverse relaxation time of alkali-metal atoms, three measuring methods are analyzed, which are modified free induction decay method, broadening-fitting method of magnetic resonance response curve and ratio-fitting method of transverse component of the magnetic moment in the rIn order to accurately measure the short transverse relaxation time of alkali-metal atoms, three measuring methods are analyzed, which are modified free induction decay method, broadening-fitting method of magnetic resonance response curve and ratio-fitting method of transverse component of the magnetic moment in the rotating coordinate system. The transverse relaxation time of rubidium atom vapor in a cell in the magnitude of 10 μs is measured with the above three methods. Experimental results show that these three methods can reach the precision in the magnitude of 1 μs . Through analyzing the experimental condition, the modified free induction decay method and ratio-fitting method can give accurate transverse relaxation time for atomic magnetometer. And broadening-fitting method can be used to research the relaxation mechanism without light..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 602002 (2015)
Integrating Design of a Compact Optical System for Space Laser Cooling Application
Qu Qiuzhi, Xia Wenbin, Wang Bin, Lü Desheng, Zhao Jianbo, Ye Meifeng, Ren Wei, Xiang Jingfeng, and Liu Liang
An optical assembly, designed for the cold atomic clock of space experiment, is described. This optical system is used for atomic cooling, moving molasses, state preparing and clock signal detecting under microgravity environment in space. Distributed Bragg reflection (DBR) lasers has been firstly used in laser coolingAn optical assembly, designed for the cold atomic clock of space experiment, is described. This optical system is used for atomic cooling, moving molasses, state preparing and clock signal detecting under microgravity environment in space. Distributed Bragg reflection (DBR) lasers has been firstly used in laser cooling of 87Rb atoms in space. All the optical and mechanical components are integrated in a 300 mm × 290 mm × 10 mm aluminum silicon carbide baseplate. Comparing with the conventional optical systems for laser cooling, the system is more compact, more robust and miniaturized. This optical setup has operated for about one year in fountain clock, ground tested by the rigorous tests of thermal and mechanical vibration, keeping high performance with no alignment needed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 602003 (2015)
Electric Field Ionization of Lithium Atom
Ma Xuewei, Ma Xiaodong, and Dai Changjian
Electric field ionization of the Li 25P Rydberg state is studied theoretically with the three-step resonant excitation，2S1/2—2P3/2—3D3/2—25P ，and ionized by an external electric-field pulse. The rate equations for the related particle population of different atomic states are set up for the above process, from which thElectric field ionization of the Li 25P Rydberg state is studied theoretically with the three-step resonant excitation，2S1/2—2P3/2—3D3/2—25P ，and ionized by an external electric-field pulse. The rate equations for the related particle population of different atomic states are set up for the above process, from which the analytic solutions of the particle populations of different states and ionization efficiency are derived with the Laplace transformation. In order to explore the physical mechanism and characteristics of each step during the process, a home-made Matlab programs is written. The impact of both parameters of laser and electricfield pulses used in photoexcitation and electric-field ionization processes on the ionization probability has been analyzed quantitatively. The study indicates that with the present excitation scheme photoexcitation efficiency of the 25P Rydberg state is hard to be improved significantly, leading to the limitation of overall efficiency of the electric-field ionization..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 602004 (2015)
Fiber Optics and Optical Communications
Research on Multi-Channel Optical Fiber Fabry-Perot Sensing Demodulation System Based on LED Modulation and Optical Fiber Array
Jiang Junfeng, Qin Zunqi, Wang Shuang, Liu Tiegen, Liu Kun, Yin Jinde, Zou Shengliang, Shi Junfeng, and Cao Xiao
A multi-channel optical fiber Fabry-Perot (F-P) sensing demodulation system based on light emitting diode (LED) pulse demodulation and optical fiber array is proposed. Based on multi-channel optical path difference distribution theory model, multi- channel parallel light path is realized with optical fiber array and LEA multi-channel optical fiber Fabry-Perot (F-P) sensing demodulation system based on light emitting diode (LED) pulse demodulation and optical fiber array is proposed. Based on multi-channel optical path difference distribution theory model, multi- channel parallel light path is realized with optical fiber array and LED pulse demodulation is used for channel switching, which alleivates the temperature rising of positive- negative (PN) junction and the influence of the PN′s rising temperature on demodulation. The experiments investigate the effects of pulse duty cycle and modulation frequency. The results show that the demodulation can be in good perfermance when duty cycle is less than 60% and the modulation frequency is higher than 35 Hz. Using pulse modulation with 50 Hz and 12.5% duty cycle, the experiment results show that the 8-channel system has good channel consistency, and the modulation precisions of all 8 channels are less than 0.045% in full scale(F.S.)..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 606001 (2015)
Design of a New Spool for Fiber Coil Based on Cross Winding Pattern
Li Xuyou, Ling Weiwei, Xu Zhenlong, and Wei Yanhui
A turn-by-turn quantization thermal-induced bias error model for fiber coil is established. Based on the model, the effects of the fiber coil with cross winding and quadrupole (QAD) winding on the temperature performance of interferometric fiber optic gyroscope are analyzed comparatively, which shows cross winding coilA turn-by-turn quantization thermal-induced bias error model for fiber coil is established. Based on the model, the effects of the fiber coil with cross winding and quadrupole (QAD) winding on the temperature performance of interferometric fiber optic gyroscope are analyzed comparatively, which shows cross winding coil has more wonderful temperature performance than the QAD winding coil. Furthermore, the traditional spool of the QAD winding coil is redesigned for cross winding coil. The thermal-induced bias error of the new and traditional spool with cross winding coil are analyzed under the same temperature gradient. The results show that the new spool has critical influence to complete optimal properties of cross winding coil, and it can lower the thermalinduced rate error of an order of magnitude, which verifies the theoretical analysis..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 606002 (2015)
Calculation Method of Strain and Temperature Coefficients for Fibers with Multimode Acoustic Waveguide Structure
Wang Xue, Lu Yuangang, Zhang Xuping, Wang Feng, and Li Mi
A theoretical calculation method is reported for obtaining strain and temperature coefficients of fibers with multimode acoustic waveguide structure in distributed optical fiber sensing based on Brillouin beat spectrum power measurement. The power of the Brillouin beat spectrum relates to the fiber’s effective refractiA theoretical calculation method is reported for obtaining strain and temperature coefficients of fibers with multimode acoustic waveguide structure in distributed optical fiber sensing based on Brillouin beat spectrum power measurement. The power of the Brillouin beat spectrum relates to the fiber’s effective refractive index, Young’s modulus, Poisson’s ratio and acousto-optic effective area, and these fiber’s parameters change with the strain and temperature in the fiber. When the profile of refractive index for a studied fiber is available, the Brillouin beat power-strain coefficients and Brillouin beat power-temperature coefficients of fibers with multimode acoustic waveguide structure are deduced by establishing the relationship between Brillouin beat power and strain and temperature. The large effective area fiber (LEAF) is taken as an example to calculate the strain and temperature coefficients of the LEAF and the results are compared with experimental measurements. The results show that the theoretical calculated values obtained by using this method are consistent with the experimental values, and thus the effectiveness of the proposed calculation method is verified..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 606003 (2015)
Fourier Optics and Signal Processing
Sorting of Orbital Angular Momentum States of Light
Shi Shuai, Ding Dongsheng, Zhou Zhiyuan, Li Yan, Zhang Wei, and Shi Baosen
While light carrying orbital angular momentum (OAM) has much potential in increasing the bandwidth of communication networks, sorting of different OAM states is one of the key techniques to utilize it effectively. A method is proposed to realize optical coordinate transformation between two Fourier planes with the aid While light carrying orbital angular momentum (OAM) has much potential in increasing the bandwidth of communication networks, sorting of different OAM states is one of the key techniques to utilize it effectively. A method is proposed to realize optical coordinate transformation between two Fourier planes with the aid of spatial light modulator. After the transformations, the phase of light depending on azimuthal angle is changed to depend on transverse position. Each OAM state is focused to a lateral position after a phasecorrecting element. This method realizes sorting of light with OAM efficiently..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 607001 (2015)
Imaging Systems
Analysis of Influence of Image Motion on Auto-Focus Precision for High Resolution Aerial Camera
Meng Fanhao, Ding Yalin, Wang Dejiang, Xiu Jihong, Xu Yongsen, Ma Tianxiang, and Sun Chongshang
In the use of real-time auto-focusing technology based on image processing of long range and high resolution aerial camera, the precision decreases due to the influence of image motion. Currently there is no universal theory and exact conclusion on the relationship between image motion and auto-focusing precision. The In the use of real-time auto-focusing technology based on image processing of long range and high resolution aerial camera, the precision decreases due to the influence of image motion. Currently there is no universal theory and exact conclusion on the relationship between image motion and auto-focusing precision. The models of linear motion and jitter are analyzed theoretically, and the mathematical formulas illustrated the influence of image motion on auto-focusing measures are given. The image motion has a negative correlation to maximum value of focusing curve, the larger amounts of image motion, the smaller maximum value of the auto-focus measures. The best focusing position is located at the top of the fitting curve, by making use of the quadratic fitting technology to get auto-focusing curve. The motion base platform for auto-focusing is designed and set up. Experimental results show that when the image motion increases from 1 pixel to 5 pixel, the maximum value of curve decreases from 95.95% to 87.64% . At the same time, the best auto-focusing position on fitting curve is in the high resolution aerial camera’s half depth of focus. This result proves the correctness of image motion theoretical analysis..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 611001 (2015)
Ameliorated Method of Intensity Correlation Imaging Towards High-Orbit Satellites
Gao Xin, Li Xiyu, Tang Jia, and Lu Changming
In the process of high-orbit target imaging with intensity correlation method, the low detecting signal to noise ratio and inaccurate phase retrieval algorithm seriously affect the imaging quality. To realize the high-orbit target imaging clearly, the amelioration and optimization of estimation method to spatial spectrIn the process of high-orbit target imaging with intensity correlation method, the low detecting signal to noise ratio and inaccurate phase retrieval algorithm seriously affect the imaging quality. To realize the high-orbit target imaging clearly, the amelioration and optimization of estimation method to spatial spectral modulus and phase retrieval is discussed according to the priori information of spatial spectral distribution of high-orbit satellite, priori information of satellite images and noise distribution characteristics of intensity correlation imaging method, indoor experiment is designed to verify the validation of algorithm. Laboratory experiments indicate that the imaging quality is significantly improved as well as the ambiguous images and noise speckle reduced with improvements and optimization of estimation method of spatial spectral modulus and phase retrieval algorithm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 611002 (2015)
Analytical Analysis Method for Impact of Polarization Aberration of Projection Lens on Lithographic Imaging Quality
Shen Lina, Li Sikun, Wang Xiangzhao, and Yan Guanyong
An analytical analysis method for the impact of polarization aberration of projection lens on aerial image of alternating phase-shift mask (Alt-PSM) is proposed. Analytical expressions of image placement error (IPE) and best focus shift (BFS) caused by polarization aberration are derived. Analytical analysis for effectAn analytical analysis method for the impact of polarization aberration of projection lens on aerial image of alternating phase-shift mask (Alt-PSM) is proposed. Analytical expressions of image placement error (IPE) and best focus shift (BFS) caused by polarization aberration are derived. Analytical analysis for effect of every Pauli- Zernike polarization aberration to aerial image is realized. The linear relationships between IPE and odd items of Pauli-Zernike polarization aberrations, as well as that between BFS and even items of Pauli- Zernike polarization aberrations are established. The validity of analytical results is verified by numerical simulations, and the accuracy of linear relationships is assessed by the least square method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 611003 (2015)
Error Analysis of Electro-Absorption-Modulator-Based Depth Imaging System
Zhang Minrui, He Zhengquan, Tian Jinshou, and Wang Tao
A numerical model of electro-absorption-modulator (EAM)-based time-of-flight depth system is established. A formula with scale factor is deduced to quantify the contribution of timing-error to the accuracy of system. Measurement error is studied with parameters of EAM as well as background noise and timing-error. The rA numerical model of electro-absorption-modulator (EAM)-based time-of-flight depth system is established. A formula with scale factor is deduced to quantify the contribution of timing-error to the accuracy of system. Measurement error is studied with parameters of EAM as well as background noise and timing-error. The results show that with no timing-error the standard deviation of measurements is inversely proportional to the square root of the number of signal electrons and is proportional to the square root of the ratio of the number of background electrons to the number of signal electrons. System accuracy improved by employing EAM with high speed modulation and higher extinction ratio. With skew error increasing, measurement error rises rapidly and is difficult to be reduced by increasing the number of signal electrons in the well of sensor. The well capacity of sensor must be larger than 300 Ke and the skew error of signal must be less than ±200 ps if the accuracy of 7 m single depth image is required less than 1 cm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 611004 (2015)
An Error Correction Method Research Based on Large Field Reflecting Telescope
Zhou Longfeng, Zhang Ang, Zhang Junbo, and Xian Hao
For a two-mirror reflecting telescope, if the position of primary mirror is set as standard, the influences of de-center, tilt of a aspheric secondary mirror and de-space between primary and secondary mirrors on wavefront aberration of the felescope are analyzed. An error correction method of the telescope is proposed For a two-mirror reflecting telescope, if the position of primary mirror is set as standard, the influences of de-center, tilt of a aspheric secondary mirror and de-space between primary and secondary mirrors on wavefront aberration of the felescope are analyzed. An error correction method of the telescope is proposed based on the theory. The method firstly uses the radius of spot diagram on axis and secondly uses the mean radius of all fields spot diagrams as performance metric of imaging quality. The position of secondary mirror is adjusted by stochastic parallel gradient descent (SPGD) algorithm. Finally, the mean radius of all fields spot diagrams converge to regard as the situation of best imaging quality. The process is achieved in a Ritch-Chretien (R-C) telescope by computer simulation, and the results show that the correction of secondary mirror makes the mean radius of all fields spot diagrams converge. The method gives the error correcting of the telescope an external standard and can be used to correct error in observation process of the telescope..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 611005 (2015)
Correction of CT Image Geometric Artifacts for Unclosed Scanning Data
Yu Ping, Chen Defeng, Zhang Huitao, and Zhang Peng
For the unclosed scanning data of fan-beam computerized tomography (CT) , a correction method of geometrical artifacts based on nonlinear optimization model is proposed. The marked and measured objects are scanned by this method, and the geometric parameters of the CT system are precisely estimated by solving nonlinearFor the unclosed scanning data of fan-beam computerized tomography (CT) , a correction method of geometrical artifacts based on nonlinear optimization model is proposed. The marked and measured objects are scanned by this method, and the geometric parameters of the CT system are precisely estimated by solving nonlinear optimization model which is based on the scanning data. The geometric artifacts caused by geometric parameters and the unclosed scanning data are corrected. Simulation and experimental results verify that the correction method effectively decrease the gometric artifacts of CT images for the unclosed CT data..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 611006 (2015)
Instrumentation, Measurement and Metrology
Identification Method of Rotational Direction in Remote Angular-Velocity Measurement with Spatial Filtering Technique
Zeng Xiangkai, Chen Yang, Zhu Zhixiong, and Liu Quanshun
Based on differential subtraction correlation (DSC) and the position zones of the rotational center, an approach to identifying the rotational direction of the measured body in remote angular-velocity measurement with spatial filters is presented. The DSC is obtained by differentiating and subtracting the output signalBased on differential subtraction correlation (DSC) and the position zones of the rotational center, an approach to identifying the rotational direction of the measured body in remote angular-velocity measurement with spatial filters is presented. The DSC is obtained by differentiating and subtracting the output signals of two adjacent photovoltaic cells in one differential spatial filter (DSF), and then integrating the absolute values of the differential subtraction signal. The sign of the temporal delay at the minimum DSC value indicates the displacement direction of the moving image on the photovoltaic cells. The rotational direction is distinguished by using both the displacement direction and the position zone of the rotational center. The position zone of the rotational center is determined by a coefficient k and the location of the DSF with a larger central frequency, where k is calculated with the two central frequencies and their variations of the quasi-sinusoidal output signals of a double-DSF sensor. Experiments and simulations are achieved to confirm the identification method, of which the results show that the identification method is correct and easy to be implemented. The proposed identification method is insensitive to random phase fluctuation, and has solved the difficult problem of identifying the rotational direction in remote angular measurement with spatial filtering technique..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 612001 (2015)
Measurement of Transient Deformation Using High-Speed Temporal Speckle Pattern Interferometry
Li Xiangyu, Huang Zhanhua, Zhu Meng, Zhang Hao, and Li Xiuming
Based on the Michelson-type interferometer combined with a high-speed imaging system, the whole-field transient deformation is measured in real time by using temporal speckle pattern interferometry. With the continuous movement or deformation of the object under study, a sequence of speckle patterns is recorded to acquBased on the Michelson-type interferometer combined with a high-speed imaging system, the whole-field transient deformation is measured in real time by using temporal speckle pattern interferometry. With the continuous movement or deformation of the object under study, a sequence of speckle patterns is recorded to acquire the temporal signal of interference intensity at each pixel of the image sensor. The wrapped phase information is extracted by Hilbert transform method, which is regarded as a phase shifter of 90° , and the phase unwrapping is subsequently performed in time domain. Finally, the two-dimensional deformation field is acquired by evaluating the phase information pixel by pixel. To verify the proposed approach, the out-of-plane deformation of the object impacted by a piezoelectric ceramic transducer is measured. The experimental results demonstrate that the transient deformation can be measured by this method under the capturing rate of 1000 frame/s. Comparing with the conventional phase shifting electronic speckle pattern interferometry, the proposed method does not only yield simple implementation, but also has a relatively high spatio-temporal resolution..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 612002 (2015)
Measurements on Time-Domian Broadening of Underwater Laser Pulse Propagating Based on Depth of Gating Profile
Han Hongwei, Zhang Xiaohui, and Zhong Wei
Time-domian broadening is one of the very important features of laser pulse propagating underwater, which affects the performances of blue-green laser submarine communication system and underwater laser imaging system directly. The relationship between characteristic parameter of depth of gating (DOG) profile and that Time-domian broadening is one of the very important features of laser pulse propagating underwater, which affects the performances of blue-green laser submarine communication system and underwater laser imaging system directly. The relationship between characteristic parameter of depth of gating (DOG) profile and that of laser echo profile and intensified change coupled device (ICCD) gating profile is deduced, which is the theoretical foundation of the proposed method to measure the time-domian broadening of underwater laser pulse. With the help of the high RPF laser underwater imaging system constructed by our term, the laser pulse time-domian broadening in large-scale tank is experimentally measured. The results show that the method proposed works well and is suitable for the conditions at long range..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 612003 (2015)
Phase Retrieval Errors Analysis of Ronchi Phase-Shifting Shearing Interferometer
Wu Feibin, Tang Feng, Wang Xiangzhao, Li Jie, and Li Yong
Based on analysis of the typical system parameters of Ronchi phase shifting shearing interferometer, the main phase retrieval error sources of the interferometer are systematically studied. Combined with the traditional five-frame algorithm, retrieval phase errors of Ronchi phase-shifting shearing interferometer are anBased on analysis of the typical system parameters of Ronchi phase shifting shearing interferometer, the main phase retrieval error sources of the interferometer are systematically studied. Combined with the traditional five-frame algorithm, retrieval phase errors of Ronchi phase-shifting shearing interferometer are analyzed and simulated with the self-designed eight-frame and ten-frame phase-shifting algorithm. The simulation results show that the ten-frame phase-shifting algorithm has a better phase retrieval accuracy than the eight-frame phase-shifting algorithm and both the two algorithms can effectively eliminate negative effects of unwanted interference from the high order diffraction light, which limits the phase retrieval accuracy. In order to improve the measurement accuracy, the following conditions should be satisfied: the phase shifting error is better than 2%, at least 10-bit quantization detector is used, the grating period error is less than 1% and the spatial coherence of light is less than 0.1. The theoretical analysis is validated by three groups of comparison experiments with different phase retrieval algorithms, shear ratios and spatial coherence of light..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 612004 (2015)
Rotation Elimination and Evaluation of Length of Measuring Images without Damage of Polysiloxane Waveguide
Wen Changli, Xu Rong, Men Tao, and Liu Changhai
Recently, optical interconnection technology has become a hot research topic due to the inherent proldems of electronic interconnection technology. Organic optical waveguide plays a most important role in optical interconnection because of its own advantages. Polysiloxane optical waveguide is one of the best waveguide Recently, optical interconnection technology has become a hot research topic due to the inherent proldems of electronic interconnection technology. Organic optical waveguide plays a most important role in optical interconnection because of its own advantages. Polysiloxane optical waveguide is one of the best waveguide of 850 nm. One of the most difficult problems in research is how to realize the high precision measurement without damage for the loss of waveguide. Measurement of CCD without damage becomes the focus of research because of its simple application. This paper is based on the problems in measurement of CCD about how to ensure the transmission direction of light in measuring image to keep a high level of precision and how to evaluate the length of optical channel. Eliminating rotation theory and method of waste measuring image without damage of polysiloxane optical waveguide are proposed. The theory and method of evaluating length of optical channel are proposed, either. At last, the results are compared with the traditional cutting off method. The correctness and effective ness of the proposed method are verified..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 612005 (2015)
Detection of Multimode Spatial Correlation of Entangle Photons to Calibrate Photomultiplier Quantum-Efficiency
Xia Maopeng, Li Jianjun, Gao Dongyang, Hu Youbo, Pang Weiwei, and Zheng Xiaobing
A new calibration method of detectors based on the multimode spatial correlation of entangle photons which is generated from parametric-down-conversion is proposed and demonstrated experimentally. BBO nonlinear crystal is pumped by a continuous work ultraviolet 355 nm to generate entangle photons with wavelengths of 71A new calibration method of detectors based on the multimode spatial correlation of entangle photons which is generated from parametric-down-conversion is proposed and demonstrated experimentally. BBO nonlinear crystal is pumped by a continuous work ultraviolet 355 nm to generate entangle photons with wavelengths of 710 nm/710 nm at signal channel and 700 nm/720 nm at idle channel. The quantum efficiency is calibrated by taking the multimode correction method. The theory and calibration scheme of this novel method is presented and the system uncertainty is detailed analyzed. It is proved that the combined uncertainty of this new method is less than 4.7%. The approach presented is compared with the calibration result provided by the manufacturer, the relative difference is 10.3%, 10.2% at signal channel 12.9%, 8.95% at idle channel. The quantum efficiency of detector that doesn’t depend on time correlation measurement can be obtained by means of two branches of photons number statistics. The calibration results indicate its validity and rationality..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 612006 (2015)
Optimized Analysis of Random Point Array Illumination Source for Nanometer Accuracy Wavefront Error Testing
Lu Zengxiong, Qi Yuejing, Qi Wei, Su Jiani, and Peng Zhuojun
The uniform and high brightness illumination light is the key for testing the projection objective lens in deep ultraviolet region with nanometer accuracy by using the method of Shack-Hartmann wavefront sensor. The intensity contrast of the wavefront diffracted by the random arrangement pinhole array is optimized by usThe uniform and high brightness illumination light is the key for testing the projection objective lens in deep ultraviolet region with nanometer accuracy by using the method of Shack-Hartmann wavefront sensor. The intensity contrast of the wavefront diffracted by the random arrangement pinhole array is optimized by using finitedifference time domain method and the theory of partial coherence. The wavefront diffracted by the pinhole array with random arrangement is smoother compared with that with periodic arrangement. Analyzing the wavefront diffracted by the single pinhole shows that the larger the pinhole diameter is, the bigger the intensity contrast of the wavefront will be. The intensity contrast of the wavefront diffracted by double pinholes reaches to maximum value when their separation is 74 nm. The calculation and analysis show that, to obtain the wavefront whose intensity contrast meets the requirement of nanometer accuracy wavefront error metrology, the diameters of the pinholes in pinhole array with random arrangement should be 170 nm and their separations should not be less than 306 nm. In this case, there are 428 pinholes in the pinhole array, and the intensity contrast of the wavefront diffracted by them is 11.70..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 612007 (2015)
Lasers and Laser Optics
Parameters Optimization for Multi-color Multi-central Frequency Smoothing by Spectral Dispersion
Wen Ping, Li Zelong, Zhong Zheqiang, and Zhang Bin
Focused on the scheme of the multi-color and multi-central frequency smoothing by spectral dispersion, the effects of the main parameters on the target uniformity are numerically simulated and analyzed, including the multi-color wavelength difference, the multi-central frequency wavelength difference, the bandwidth andFocused on the scheme of the multi-color and multi-central frequency smoothing by spectral dispersion, the effects of the main parameters on the target uniformity are numerically simulated and analyzed, including the multi-color wavelength difference, the multi-central frequency wavelength difference, the bandwidth and the number of color cycle. And then, the parameters are further optimized. The results show that the target uniformity is first improved and then degraded with the increase of the multi-color wavelength difference, which means that there is an optimized multi-color wavelength difference. When the multi-central frequency wavelength difference and the bandwidth increase, the target uniformity is improved. However, neither of these two parameters could be too large since they are limited by the high efficiency of the third harmonic generation. For the given grating dispersion, the contrast of far field first decreases and then increases with the increase of the color cycle number. Therefore, the optimization is required under further analysis. The preliminary analysis indicates that the best color cycle number is not just to be one any more and changes with the parameters of the laser source and the grating..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 614001 (2015)
Electrical Pumping Organic Quasi-Crystal Laser and its Properties
Cai Yuanyuan, Chen Xiao, Li Ning, Li Changwei, and Wang Yiquan
A novel quasi-crystal microcavity slab laser is designed based on conjugated polymer MEH-PPV with excellent optical-electrical properties and the modulation of quasicrystal microcavity. The MEH-PPV is applied as the gain medium and achieve electrical-pumping 8-fold quasicrystal vertical-cavity surface-emitting laser baA novel quasi-crystal microcavity slab laser is designed based on conjugated polymer MEH-PPV with excellent optical-electrical properties and the modulation of quasicrystal microcavity. The MEH-PPV is applied as the gain medium and achieve electrical-pumping 8-fold quasicrystal vertical-cavity surface-emitting laser based on the confinement of point-defect photonic crystal structure and the reflection between anode and cathode in the vertical direction. The current threshold of laser is 0.8 mA, and the lasing action occurs at λ = 606 nm with a full width at half maximum (FWHM) of 0.5 nm, limited by the resolution of the spectrometer..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 614002 (2015)
Linear Tunable Fiber Ring Laser Based on Closed-Loop Piezoelectric ceramics
Li Guoyu, Yang Kang, Jia Sumei, Li Yan, and Liu Mingsheng
The linearity tunable fiber ring laser based on closed-loop piezoelectric ceramics (PZT) is proposed. The fiber Bragg grating (FBG) of the ring cavity is fixed on the PZT, the wavelength of FBG changes with controlling the PZT, which leads to the wavelength change of fiber ring laser, so the tunable fiber ring laser baThe linearity tunable fiber ring laser based on closed-loop piezoelectric ceramics (PZT) is proposed. The fiber Bragg grating (FBG) of the ring cavity is fixed on the PZT, the wavelength of FBG changes with controlling the PZT, which leads to the wavelength change of fiber ring laser, so the tunable fiber ring laser based on PZT is realized. The strain sensor attached on the PZT is monitoring the step change of the PZT real-timely, reporting to the PZT driver system, compensating and rectifying the inherent hysteresis and creep through the Wheatstone bridge, so the tunable fiber ring laser based on closed-loop PZT is achieved. Experimental results show that the tuning curve of the fiber ring laser is linear with the tuning range nearly of 0.9 nm and the linewidth nearly of 4 KHz. Furthermore, the wavelength fluctuations of the tunable fiber ring laser are kept within ±0.01 nm, and the power variation is kept within ±0.3 dB..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 614003 (2015)
Machine Vision
Camera Distortion Calibration Method Based on Straight Line Characteristics
Zhang Min, Jin Longxu, Li Guoning, Wu Yinan, and Han Shuangli
In the multi-view and wide-angle imaging system, in order to guarantee the quality of subsequent image mosaic, the distorted image obtained from the wide-angle camera must correct. The linear characteristics in the image is utilized to correct the distortion and a bending measurement function is put forward with weightIn the multi-view and wide-angle imaging system, in order to guarantee the quality of subsequent image mosaic, the distorted image obtained from the wide-angle camera must correct. The linear characteristics in the image is utilized to correct the distortion and a bending measurement function is put forward with weight factor that gives each curve line the different weight values in accordance with the distance from the image center as the object function for obtaining the final distortion cofficients. The optimal distortion coefficients is obtained by minimizing the objective function. And based on the engineering examples, are used respectively the traditional distortion correction method based on linear characteristics and the proposed method to correct the target distort image. Experimental results show that the proposed method can only use single image to obtain high accuracy distortion calibration coefficient, under the condition that the noise level is less than 2 pixel, the root mean square error of the corresponding coordinates within 0.3 pixel.At the same time, the proposed method is simple, convenient and easy to implement..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 615001 (2015)
Observation Consistency for Moving Object Tracking with Mobile Robot in Dynamic Environments
Wu Ming, Li Linlin, Wei Zhenhua, and Wang Hongqiao
In order to solve the problem of spatial observation consistency from heterogeneous multi-sensor in the process of simultaneous localization, mapping and object tracking (SLAMOT), a calibration optimization method of camera and laser range measuring sensor based on information fusion is proposed. Uncertain arera of lasIn order to solve the problem of spatial observation consistency from heterogeneous multi-sensor in the process of simultaneous localization, mapping and object tracking (SLAMOT), a calibration optimization method of camera and laser range measuring sensor based on information fusion is proposed. Uncertain arera of laser scanning point image plane projection is determined based on error propagation formula, and a covariance intersection based method which fuses informations come from moving object detection and Camshift method to object state estimation is designed. On this basis, the objective function is constructed with bearing error of object image projection, and calibration parameters of camera and laser range finder are optimized using nonlinear optimization method. Experiments show that the designed method improves accuracy of both object tracking and multi-sensors calibration. The method offers measurements which support further research of SLAMOT filter based on multi-sensor information fusion..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 615002 (2015)
A Direct Least Squares Method for Camera Pose Estimation Based on Straight Line Segment Correspondences
Li Xin, Zhang Yueqiang, Liu Jinbo, Zhang Xiaohu, and Yu Qifeng
In order to estimate the camera pose from straight line segment correspondences in high precision, a direct least squares solution is proposed. A straight line segment distance measurement which integrates distance between endpoints，midpoints, angle and lengths of two line segments is proposed and used to transform theIn order to estimate the camera pose from straight line segment correspondences in high precision, a direct least squares solution is proposed. A straight line segment distance measurement which integrates distance between endpoints，midpoints, angle and lengths of two line segments is proposed and used to transform the original problem into minimize a quadratic cost function of pose rotation matrix. A modified cost function based on the CGR parameters of rotation matrix is minimized, which the optimality conditions form a system of three third-order polynomial equations. Algebraic method is used to solve this system directly without requiring iterations, and the globally optimal solution of rotation matris is obtained. The complexity of proposed method is O(n). The efficiency and high precision are demonstrated by synthesized and real data experiments..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 615003 (2015)
Materials
Transmittance of Laser in the Microorganism Aggregated Particle Swarm
Zhao Xinying, Hu Yihua, Gu Youlin, and Li Le
Complex media environment which is composed of micrometer-level microorganism aggregated particle swarm has great impact on laser transmittance. To study what the impact is, based on fractal theory, a cluster-cluster aggregation (CCA) model is used to simulate the fractal structure of microorganism aggregated particlesComplex media environment which is composed of micrometer-level microorganism aggregated particle swarm has great impact on laser transmittance. To study what the impact is, based on fractal theory, a cluster-cluster aggregation (CCA) model is used to simulate the fractal structure of microorganism aggregated particles, and the single scattering extinction parameters for aggregated particles are calculated using the discrete dipole approximation (DDA) method. Then the transmittance of 10.6 μm laser in microorganism aggregated particle swarm is studied with the Monte Carlo method. The results show that when each aggregated particle contains 20~50 original particles, the radius of original particle is 1.5 μm , the density of aggregated particles is higher than 800 /cm3 , and the porosity is less than 0.9, the transmittance of 10.6 μm laser in the microorganism aggregated particle swarm which has a 4 m-thick measurement area can be less than 10%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 616001 (2015)
Analysis on Spatial Filtering by Reflecting Combination Device
Zhang Ying, Wang Yanzhi, Qi Hongji, Yi Kui, Sui Zhan, and Shao Jianda
Comparing with transmission combination filtering device, only one type of reflection element is presented in optical path of reflecting combination filtering device. The difficulty of design and preparation is largely decreased in the same angular spectrum selectivity. In addition, by comparing the design of coating sComparing with transmission combination filtering device, only one type of reflection element is presented in optical path of reflecting combination filtering device. The difficulty of design and preparation is largely decreased in the same angular spectrum selectivity. In addition, by comparing the design of coating stacks and the electric field strength, reflecting combination device has higher laser- induced damage threshold (LIDT) than the transmission. Thus, the device plays an important role in preparation and application of the dielectric multilayer film reflecting combination device..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 616002 (2015)
Research on Interlayer in “a-Si:H/μc-Si:H” Tandem Solar Cells
Tu Ye, Yang Wen, Yang Peizhi, Duan Liangfei, Zhang Liyuan, and Song Zhaoning
Tandem structure is able to improve the efficiency and stability of silicon-based thin film solar cells. The current matching of sub cells that limiting the efficiency of the tandem devices can be effectively improved by employing an interlayer. This paper introduces the structure, properties and materials of the interTandem structure is able to improve the efficiency and stability of silicon-based thin film solar cells. The current matching of sub cells that limiting the efficiency of the tandem devices can be effectively improved by employing an interlayer. This paper introduces the structure, properties and materials of the intermediate reflector and tunnel junction in“a-Si∶H/mc-Si∶H”solar cells. Based on the theoretical foundation, the concept of“tunnel recombination reflector”short for the tunnel recombination junction as a light reflector is proposed and its working principle and materials selection are discussed. In the tandem devices, such interlayer not only plays the role of intermediate reflector that enhances light-trapping, but also optimizes the tunnel junction to improve charger carrier collection..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 616003 (2015)
Optical Design and Fabrication
Ultra-Gradient Mirror Figuring by 5-Axis Ion Beam
Ma Zhanlong, Gu Yongqiang, Peng Lirong, and Wang Gaowen
In order to verify the machining capability of ultra-gradient mirror figuring by ion beam, the figuring of ultra-gradient mirror by 5-axis ion beam is investigated. First, based on the existence measure condition, the experiment scheme is presented and the surface figure date is processed. The dwell time of the area exIn order to verify the machining capability of ultra-gradient mirror figuring by ion beam, the figuring of ultra-gradient mirror by 5-axis ion beam is investigated. First, based on the existence measure condition, the experiment scheme is presented and the surface figure date is processed. The dwell time of the area exceed the machine range is compensated. Then the post processing for 5-axis ion beam figuring machine is established, the numerical control generate software is programed based on the post processing, and the correctness of the numerical control program is verified through experiment. Finally, the off-axis figuring experiment of ultra-gradient mirror by 5-axis ion beam is carried out, and through five iterations, the surface figure is improved from initial condition: the peak valley (PV) value is 57.983 nm, the root mean square (RMS) value is 9.406 nm to final condition: PV value is 11.616 nm, RMS value is 1.306 nm. Convergence ratio reaches 7.20. The results indicate that ultra-gradient sphere mirror can be figured by 5-axis ion beam figuring machine to achieve high efficiency and precision, and the figuring of off-axis mirror by ion beam figuring is verified at the same time..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 622001 (2015)
Design of Large Relative Aperture Infrared Athermalized Optical System with Chalcogenide Glasses
Shi Haodong, Zhang Xin, Qu Hemeng, Zhang Jizhen, and Jiang Huilin
According to the characteristics of chalcogenide glass with high thermal stability, perfect spectrum transmittance and moldable property, a design method for long-wave infrared optical systems only with chalcogenide glasses is proposed. The design process of passive optical athermalization and passive mechanical athermAccording to the characteristics of chalcogenide glass with high thermal stability, perfect spectrum transmittance and moldable property, a design method for long-wave infrared optical systems only with chalcogenide glasses is proposed. The design process of passive optical athermalization and passive mechanical athermalization is analyzed. The initial optical power contribution is calculated based on the theory of passive optical athermalization. An infrared athermalized optical system is designed. The focal length is 90 mm, the Fnumber is 0.9. This system is compatible with uncooled long-wave infrared (8~14 μm) focal plane array which has a format of 640 pixel × 512 pixel and a pixel pitch of 17 μm. It can adapt within the temperature range of -40 ℃~50 ℃ , the modulation transfer function (MTF) of full field of view is close to the diffraction limit through the entire temperature range. The results show that the passive athermalization can be realized by matching chalcogenide glasses and using passive mechanical compensation, and the low-cost infrared imaging optical system can be achieved..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 622002 (2015)
Study on Interference Null Compensator Testing
Yao Jingang, Zhang Jinping, Zheng Liehua, and Hao Peiming
Null testing is the main measurement for aspheric surface in modern optical testing. In order to improve null testing, a novel measurement which combines compensator and interference is proposed. The principle of the method is that the radius of the first surface of the compensator is chosen to equal the distance betweNull testing is the main measurement for aspheric surface in modern optical testing. In order to improve null testing, a novel measurement which combines compensator and interference is proposed. The principle of the method is that the radius of the first surface of the compensator is chosen to equal the distance between surface and laser point of interference. The reference wavefront reflected from the concentric surface inferred with the wavefront from the aspheric surfaces under test to accomplish the interference null testing. Base on third-order aberration theory, interference null testing system is designed and the residual aberrations are calculated. The wavefront abberation of designed system is better than λ/170 , if the relative aperture is smaller than 1/4.5. By means of theoretic test, this measurement is proved to be available for testing aspheric surface..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 622003 (2015)
Designing of Lateral Support System for an 8 m Active Thin Mirror
Dai Xiaolin, Xian Hao, Tang Jinlong, and Zhang Yudong
The support system of an thin primary mirror consists of axial supports and lateral supports. Lateral supports mainly support the component force of the mirror’s gravity normal to the optical axis of the mirror. The push- pull- shear lateral support and the principle of active correction are introduced, and 5 alternatiThe support system of an thin primary mirror consists of axial supports and lateral supports. Lateral supports mainly support the component force of the mirror’s gravity normal to the optical axis of the mirror. The push- pull- shear lateral support and the principle of active correction are introduced, and 5 alternative lateral supports are designed for an 8 m active thin mirror. Taking account of the active correction of the primary mirror and comparing the 5 alternatives via the finite element method, the best lateral support of the 8 m mirror is determined. The best lateral support consists of 64 lateral support points, and each point only applies an tangential force. The root mean square of the surface of the 8 m mirror after active correction is 19.2 nm when the mirror is mounted vertically and the range of the correction forces is - 318.9~301.4 N. Compared with regular push- pull- shear lateral support, this lateral support is simpler in structure, easier to implement and has good supporting performance..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 622004 (2015)
Simulation Model Based on Equivalent Layer Method for Defective Mask Multilayer in Extremeultra violet Lithography
Liu Xiaolei, Li Sikun, and Wang Xiangzhao
A model based on the equivalent layer method is developed to simulate defective mask multilayer in extreme ultraviolet (EUV) lithography. In this model, the defective multilayer is divided into defect free region and defective region. The reflection coefficients of two regions in different locations are computed by theA model based on the equivalent layer method is developed to simulate defective mask multilayer in extreme ultraviolet (EUV) lithography. In this model, the defective multilayer is divided into defect free region and defective region. The reflection coefficients of two regions in different locations are computed by the equivalent layer method. The spectrum of defective multilayer can be obtained fast and accurately. Simulation time of the proposed model is 1/9 times that of the waveguide method for a multilayer of 200 nm size. Compared with advanced single surface approximation (SSA) model and the simplified model based on SSA, the simulation accuracy of the multilayer spectrum and aerial image of the proposed model is improved. The errors of simulated amplitude and aerial image are also with little fluctuation in different defect sizes and incidence angles. Taking + 1 order diffraction as an example, compared with advanced SSA model and the simplified model based on SSA, in 6° incidence angle, the simulated amplitude error of the proposed model decreased as much as 77% and 63%, respectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 622005 (2015)
Optical Devices
Filter Characteristic Research of MIM Waveguide Based on L Shaped Resonator
Pang Shaofang, Qu Shixian, Zhang Yongyuan, Xie You, and Hao Limei
A metal-insulator-metal (MIM) waveguide with L-shaped resonator is designed. The transmission properties of this resonator are numerically investigated by finite element method. The results show that the transmission properties of the L- shaped resonator depend on the length and the height of it. L- shaped cavity has bA metal-insulator-metal (MIM) waveguide with L-shaped resonator is designed. The transmission properties of this resonator are numerically investigated by finite element method. The results show that the transmission properties of the L- shaped resonator depend on the length and the height of it. L- shaped cavity has better quality factor and better filtering effect compared with the horizontal rectangular cavity with the same size as L- shaped cavity. With the increase of the size of L- shaped cavity, spectrum exhibits a red shift. Filling the medium of different refractive index in L- shaped cavity, the MIM waveguide with L- shaped resonator allows a much more sensitive detection of small refractive index changes of the filled media inside Lshaped nano-cavity. It is easy to detect the refractive index of medium by detecting resonant wavelength in the transmission spectra, which reveals a potential sensors of the MIM waveguide with L-shaped nano-cavity..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 623001 (2015)
Study of Green Phosphorescent Microcavity Organic Light-Emitting Devices
Zhang Chunyu, Wang Qingkai, Rong Hua, and Qin Li
Green phosphorescent microcavity organic light-emitting devices (MOLEDs) in a architecture of Glass/DBR/ITO/MoO3(1 nm) /TcTa(40 nm)/ CBP:Ir(ppy)3(40 nm,6%)/TPBI(47 nm)/LiF(1 nm)/Al(80 nm) using typical green phosphorescent Ir(ppy)3 as luminous layer, DBR and Al as a pair of reflector of microcavity are fabricated. For Green phosphorescent microcavity organic light-emitting devices (MOLEDs) in a architecture of Glass/DBR/ITO/MoO3(1 nm) /TcTa(40 nm)/ CBP:Ir(ppy)3(40 nm,6%)/TPBI(47 nm)/LiF(1 nm)/Al(80 nm) using typical green phosphorescent Ir(ppy)3 as luminous layer, DBR and Al as a pair of reflector of microcavity are fabricated. For comparison, OLED without cavity is also developed to investigate the effect of microcavity structure on luminescent properties of phosphorescent devices. The peak of electroluminescence (EL) spectrum of OLED is 510 nm, and the full-width at half-maximum (FWHM) is 70 nm. The peak of MOLED is 514 nm and the FWHM is 35 nm.The FWHM of MOLED is reduced by half for the OLED without microcavity. Compared with the EL spectrum of non-cavity OLEDs, the linewidth of MOLED is narrowed. Also, the colour purity of MOLED is improved. For MOLED, the maximum brightness and the maximum current efficiency are 143000 cd/m2 and 64.4 cd/A, respectively. The maximum brightness and current efficiency of OLED are 103000 cd/m2 and 41.6 cd/A. The maximum external quantum efficiency (EQE) of the device is tested and calculated, and the maximum EQEs of MOLED and OLED are 18.6% and 14.3% , respectively. The experimental results show that the luminescence properties of microcavity devices are improved greatly compared with that of the no-cavity devices..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 623002 (2015)
Hybrid Surface Plasmon Polariton Waveguide of Low-Loss and Ultra-Small Modal Area
Xu Dan, Huang Yonggang, Wang Xiaoyun, He Hao, and He Hailong
A novel hybrid waveguide structure of rectangular silicon insert two identical nuclei in a rectangular metal trench is presented. Based on the finite element method, variations of effective mode area and propagation distance with distance between the two nuclear medium, nuclear medium height and width, the distances beA novel hybrid waveguide structure of rectangular silicon insert two identical nuclei in a rectangular metal trench is presented. Based on the finite element method, variations of effective mode area and propagation distance with distance between the two nuclear medium, nuclear medium height and width, the distances between dielectric core and metal are systematic studied at a wavelength of 1550 nm. Calculated results show that the enhanced effect of field in gaps of the dielectric core or between dielectric core and metal can get a low loss hybrid mode of ultra-small modal area. When the distances between dielectric core and metal is wide, the gap in dielectric core is 5 nm, effective mode area of the structure is drastically reduced to about one-seventh respect to the nuclear medium with no gap and the propagation distance increasing a slight remains at 50 wavelengths around. And the smaller the mode area is, the longer the propagation distance is. The higher the gap dielectric core is, the smaller the propagation distance is, and the mode area is almost invariably. When the height of dielectric core is higher, the propagation distance is longer, but the effective mode area changes minor. When the distance between dielectric core and metal is narrow, the gap of nuclear medium and nuclear medium width are much narrower, the effective mode area are smaller..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 623003 (2015)
Effect of Decenter Errors on Diffraction Efficiency of Multilayer Diffractive Optical Elements in Long Infrared Waveband
Gao Long, Xue Changxi, Yang Hongfang, and Nie Xin
Based on the expression of phase delay and the expression of diffraction efficiency of diffractive optical elements (DOEs), the expression of diffraction efficiency of multilayer diffractive optical elements (MLDOEs) is described. The mathematical analysis model of diffraction efficiency for MLDOEs with decenter error Based on the expression of phase delay and the expression of diffraction efficiency of diffractive optical elements (DOEs), the expression of diffraction efficiency of multilayer diffractive optical elements (MLDOEs) is described. The mathematical analysis model of diffraction efficiency for MLDOEs with decenter error is presented, and effects of decenter error on diffraction efficiency and polychromatic integral diffraction efficiency of MLDOEs are analyzed in long infrared waveband of 8~12 μm . ZnS and Ge are selected as the material of first and second harmonic diffractive optical elements respectively for the MLDOEs, the design wavelengths λ1 and λ2 are determined with 8.79 μm and 11.11 μm . The micro- structure height of MLDOEs are 78.3391 μm and 34.6076 μm , respectively. Finally, with the period width of MLDOEs 500 μm and 1000 μm , the range values of decenter error must be smaller than 5.8 μm and 11.71 μm when polychromatic integral diffraction efficiency is greater than 95% . The analysis model of diffraction efficiency with decenter error is important to manufacture and design process of MLDOEs..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 623004 (2015)
Physical Optics
Investigation of Thermally Induced Birefringence Effect in Natural Birefringent Crystals
Miao Qingjie, Pan Sunqiang, Liu Bin, Xiang Zhen, and Chen Jun
The thermal effects in laser crystals have important influences on the properties of laser beams in a laser resonator and an amplifier. They not only change the beam wave fronts, but also affect the polarization states of the beams. Based on the elasto-optic effect of laser crystal, the thermally induced birefringence The thermal effects in laser crystals have important influences on the properties of laser beams in a laser resonator and an amplifier. They not only change the beam wave fronts, but also affect the polarization states of the beams. Based on the elasto-optic effect of laser crystal, the thermally induced birefringence effect in natural birefringent crystals is investigated. It is showed that the effect of the elasto- optic effect on optical indicatrix in natural birefringent crystals is characterized by elliptical principal axis deflection in the cross section. The deflection angle of the principal axis is less than 0.01°. If a linearly polarized beam passes through a natural birefringent crystal with thermal effects in a laser resonator or an amplifier, the depolarization ratio is less than 1.8 × 10- 8. In this condition, the effect of the thermally induced birefringence effect can be ignored. This characteristic is quite different with that in the optically isotropic crystals..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 626001 (2015)
Study on the Fabrication and Properties of a Micro Three-Dimension Array Doped with Fluorescent Material
Hu Xuefang, He Rushuang, Tao Weidong, and Dong Jianfeng
Rhodamine 6G is doped into the photoresist which is made by mixing the 2-benzyl-2-(dimethylamino)- 4′-morpholino-butyroph and Pentaerythritol triacrylate. A 3×3 micro hexagonal pyramid array is fabricated based on the technology of femtosecond two photons by using the above photoresist. The height and length at thRhodamine 6G is doped into the photoresist which is made by mixing the 2-benzyl-2-(dimethylamino)- 4′-morpholino-butyroph and Pentaerythritol triacrylate. A 3×3 micro hexagonal pyramid array is fabricated based on the technology of femtosecond two photons by using the above photoresist. The height and length at the bottom of the hexagonal pyramid are 39 μm and 20 μm , respectively, the period of the micro hexagonal pyramid array is 60 μm. When the sample is irradiated by the 532 nm green laser, compared with the sample without Rhodamine 6G, an emission peak is found around the wavelength of 550 nm. When compared with the spectrum of the Rhodamine 6G, it is found that the peak is caused by the microstructure doped with the Rhodamine 6G. The diffraction of the sample is measured, the difference of the period between the prediction from the diffraction of the sample and designed value is 2.3%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 626002 (2015)
Spectroscopy
Quantitative Analysis of Pb in Water Based on Multivariate Calibration with LIBS
Hu Li, Zhao Nanjing, Liu Wenqing, Fang Li, Wang Yin, Meng Deshuo, Yu Yang, Gu Yanhong, Wang Yuanyuan, Ma Mingjun, Xiao Xue, Wang Yu, and Liu Jianguo
Complex components of lakes and water difference between different sampling points contribute to the matrix effect influence on precision and accuracy of quantitative analysis with laser induced breakdown spectroscopy (LIBS). To reduce the fluctuation of system parameters and the matrix effect caused by the sample enriComplex components of lakes and water difference between different sampling points contribute to the matrix effect influence on precision and accuracy of quantitative analysis with laser induced breakdown spectroscopy (LIBS). To reduce the fluctuation of system parameters and the matrix effect caused by the sample enrichment and water quality difference, characteristic spectral lines of the element under test are corrected with the background and the internal standard element. The influence of different input vectors on support vector regression (SVR) model is studied, including the peak intensity, integral intensity and signal to background ratio. Comparison results show that the effect of SVR model with binary input vector of signal to background ratio and intensity corrected by internal standard element is the best, and the root mean square error and the correlation coefficient of training set are 0.367 and 0.981, respectively, and the relative standard deviation and the average relative error of test set are 4.5% and 12.1% respectively. Multiple input vector carrying more characteristic spectral lines can effectively reduce the influence of parameter fluctuations and substrate difference. The experimental conclusion provides reference for data input in LIBS quantitative analysis of heavy metals in natural water..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 630001 (2015)
Design of Optical System for Miniature Visible/Near-Infrared Real-Time Imaging Spectrometer
Liu Bing, Liu Ying, Li Can, Wang Jian, Li Chun, and Sun Qiang
In order to solve the problem in traditional spectral imaging spectrometers that the spectral and image information cannot be acquired at the same time, a new type of real-time imaging spectrometer working in visible/near-infrared wide spectral range is designed. Different from traditional push-broom imaging spectrometIn order to solve the problem in traditional spectral imaging spectrometers that the spectral and image information cannot be acquired at the same time, a new type of real-time imaging spectrometer working in visible/near-infrared wide spectral range is designed. Different from traditional push-broom imaging spectrometers, the system is with multi-slits imaging technology that the spectral image of target is divided into several areas to achieve large field of spectrum. The system reasonably adopts low-dispersion optical glass and doublet lens to achieve aberration correction among wide spectral range. The front telescope objective system is a combination of complex double Gaussian structure to achieve small distortion and uniform illumination at slits for different fields of view. The image of telescope objective system is divided into two parts by prisms, and high spatial resolution of video monitoring and high spectral resolution of spectrometer are obtained. One part is received by a high-resolution panchromatic camera and the other is received by a grayscale camera. Triplet prisms are used as dispersion components. By optimizing the angle of prisms and controlling the actual light, a coaxial optical path and dispersion linearity is achieved with CaF2-silica-CaF2 structure. The results are as follows: spectral range of the optical system is 400~1000 nm, F number is 3.5, modulation transfer function (MTF) of distortion is lower than 0.1%, illumination uniformity at image plane is higher than 98%, and MTF of the front telescope objective system is more than 0.5 at the Nyquist frequency. The designed MTF of the optical system is more than 0.44 at the Nyquist frequency and spectral resolution is 10 nm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 630002 (2015)
Estimation of Sulfur Dioxide Emission from Power Plant Using Imaging Differential Optical Absorption Spectroscopy Technique
Liu Jin, Si Fuqi, Zhou Haijin, Zhao Minjie, Dou Ke, Wang Yu, and Liu Wenqing
A method for measuring the two-dimensional distribution of air pollutants from power plant-imaging differential optical absorption spectroscopy (IDOAS) technique is introduced. It is based on an imaging spectrometer combining with a rotating platform, which can realize two-dimensional scanning and hyperspectral measureA method for measuring the two-dimensional distribution of air pollutants from power plant-imaging differential optical absorption spectroscopy (IDOAS) technique is introduced. It is based on an imaging spectrometer combining with a rotating platform, which can realize two-dimensional scanning and hyperspectral measurement of the target area. The spectrum is calculated using the differential optical absorption spectroscopy (DOAS) algorithm to get two-dimensional distribution of pollutant gas in the area. Then the diffusion trend of pollutant can be further analyzed. The ground-based IDOAS system and its principle are introduced, and a field experiment is performed. During the field experiment, the two-dimensional distribution of SO2 from power plant smoke plume is acquired, realizing the visualization of power plant emissions. The SO2 emission rate and average concentration estimation method is analyzed combining with wind speed. The power plant SO2 emission rate and average concentration is evaluated respectively as 210 kg/h and 6.7 mg/m3..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 630003 (2015)
Analysis and Correction of Slit Curvature in Spectrograph with High NA
Li Zhe, Yu Anlan, Zuo Duluo, and Wang Xinbing
Slit curvature becomes an important factor which introduces the decline of spectral resolution in the developing of spectrograph with high NA. Slit curvature is corrected according to the correction formula obtained from the grating equation of off- axis ray. To cope with the problem that the real image of spectral linSlit curvature becomes an important factor which introduces the decline of spectral resolution in the developing of spectrograph with high NA. Slit curvature is corrected according to the correction formula obtained from the grating equation of off- axis ray. To cope with the problem that the real image of spectral lines usually deviate from the formula at ideal condition, calibration with a spectral lamp which has lines distributed across the full span of the spectrograph is used to fit out the assembly error parameters. Neon lamp is used to fit out these parameters, slit curvature in the spectral image of krypton lamp and fluorescent lamp of mercury vapor is corrected with these parameters. Resolution has be significantly improved, which is nearly close to the spectral resolution limit of the spectrograph when irradiated by a spot light source..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 630004 (2015)
Discrimination of Camellia Oil Adulteration by NIR Spectra and Subwindow Permutation Analysis
Sun Tong, Wu Yiqing, Li Xiaozhen, Xu Peng, and Liu Muhua
In order to crack down on camellia oil adulteration and protect the legitimate interests of consumers, near infrared (NIR) spectroscopy and subwindow permutation analysis (SPA) are used to detect complex adulteration of camellia oil (adulterated with soybean oil, colza oil, peanut oil and mixed oil). The NIR spectra ofIn order to crack down on camellia oil adulteration and protect the legitimate interests of consumers, near infrared (NIR) spectroscopy and subwindow permutation analysis (SPA) are used to detect complex adulteration of camellia oil (adulterated with soybean oil, colza oil, peanut oil and mixed oil). The NIR spectra of 85 pure camellia oil samples and 315 adulterated camellia oil samples are acquired, and the SPA method is used to select important wavelength variables. After that, partial least squares-linear discriminant analysis (PLS-LDA) is used to develop calibration models for adulteration detection of camellia oil, and the result is compared to the models developed by PLS-LDA with other selection methods such as competitive adaptive reweighted sampling (CARS) and uninformative variable elimination (UVE). The results indicate that NIR spectroscopy combined with SPA method is feasible for complex adulteration detection of camellia oil, the error rate, sensitivity and specificity of classification in prediction set are 0, 1 and 1, respectively. SPA method is superior to UVE method, and is comparable with CARS method. It is an effective variable selection method, and can simplify model, improve model prediction precision and stability..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 630005 (2015)
Studies on Improving Measurement Sensitivity of HONO Based on Second Harmonic Wavelength Modulation Technology
Cui Xiaojuan, Dong Fengzhong, Zhang Zhirong, Pang Tao, Xia Hua, Wu Bian, and Sun Pengshuai
Nitrous acid is one of the major sources of atmospheric cleaner OH radical, and its impact on the atmospheric oxidation potential is the hotspot of the atmospheric physical chemistry research in recent years. However, due to the low concentration of nitrous acid in the atmosphere, and its reactivity, solubility and phoNitrous acid is one of the major sources of atmospheric cleaner OH radical, and its impact on the atmospheric oxidation potential is the hotspot of the atmospheric physical chemistry research in recent years. However, due to the low concentration of nitrous acid in the atmosphere, and its reactivity, solubility and photolysis, real-time accurate measurement of nitrous acid is very difficult. The results of trace HONO detection using wavelength modulation technology based on the 1255 cm-1 room-temperature continuous wave quantum cascade laser are reported, the minimum detectable HONO concentration of 6.95 μg/m3 which is detected by direct absorption method reaches up to 0.84 μg/m3 in 1 s integrated time. The optimal integrated time of the system can reach 100 s by Allan variance analysis, the corresponding time detection limit is 0.34 μg/m3 . HONO in the air of the laboratory is successfully detected using this system, which proves that the system can satisfy the requirements of detection limit for the actual atmospheric measurement..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 630006 (2015)
Ultra-High-Resolution Spectrometry Incorporating Two-Dimension Dispersing Spectrometer and Tunable Fabry-Perot Filter
Liu Wenjuan, Hu Chengzhi, Jiang Peipei, Wu Bo, and Shen Yonghang
A new method for hyperfine spectrum measurement is mentioned and experimentally demonstrated. Ultra-high-resolution spectrometry is obtained through incorporating a two-dimensional (2-D) dispersing CCD spectrometer and a tunable Fabry- Perot (F- P) filter and the spectral resolution of the 2- D dispersing CCD spectromeA new method for hyperfine spectrum measurement is mentioned and experimentally demonstrated. Ultra-high-resolution spectrometry is obtained through incorporating a two-dimensional (2-D) dispersing CCD spectrometer and a tunable Fabry- Perot (F- P) filter and the spectral resolution of the 2- D dispersing CCD spectrometer is better than that of the tunable F-P filter. The F-P scanning interferometer covers a wavelength range of 780~840 nm with a free spectral range (FSR) of 3.75 GHz and a fineness of 100. With the use of 2- D dispersing CCD spectrometer consisting of a virtually-imaged phased-array (VIPA) and a diffraction grating, realtime high- resolution spectral measurement has been realized in a wide spectral range. Resolution as high as 0.7 GHz obtained with the 2-D dispersing CCD spectrometer in a spectral range of 17.4 nm (792~809.4 nm), is higher than that of the tunable F- P filter. By combining the 2- D spectrometer with a tunable F- P based scanning interferometer, hyperfine spectral resolution higher than 37.5 MHz is achieved. The laser spectrum of the modelocked Ti:sapphire laser is measured with the spectrometer, proving that its longitudinal mode with the spacing of 76.3 MHz can be distinguished clearly..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 630007 (2015)
Thin Films
Indium Tin Oxide Thin Films Defrosting Using Multiphase AC Design for Antarctic Optical Telescope
Zheng Yi, Zhao Ding, Yuan Xiangyan, Wang Jinfeng, and Zhang Kaiyuan
For optical system working in the polar environment, such as Antarctic Dome A, ITO film defrosting has outstanding advantage. The principle of ITO film defrosting is introduced. Present heating design for DC load with spot electrodes has several limitations: large area of local insufficient heating, electrode area overFor optical system working in the polar environment, such as Antarctic Dome A, ITO film defrosting has outstanding advantage. The principle of ITO film defrosting is introduced. Present heating design for DC load with spot electrodes has several limitations: large area of local insufficient heating, electrode area overheating and uneven distribution on the whole surface. These affect imaging quality and defrosting effect. The evaluation index for defrosting effect is given, and then the new design of multiple-phase AC load with linear electrodes is put forward. It is analyzed using main path method. Targeting Antarctic Survey Telescope (AST), a 500 mm aperture mirror is studied using finite element method: each heating design is evaluated under equal power condition. The actual mirror is measured by infrared thermal imager. Using the new design, mean square deviation of mirror temperature reduces by 81.65% and peak to valley by 76.31%. The experimental results validate that the design of multiple phase AC load with linear electrodes greatly improves defrosting homogeneity, effectiveness and seeing. It will be applied to Antarctic optical telescope engineering..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 631001 (2015)
Analysis of Amorphous Silicon Passivation Layer in Heterojunction Solar Cells by Spectroscopic Ellipsometry
Guo Wanwu, Zhang Liping, Bao Jian, Meng Fanying, Chen Yifeng, Feng Zhiqiang, and Liu Zhengxin
The properties of hydrogenated amorphous silicon (a-Si:H) thin layer are studied by spectroscopic ellipsometry (SE) measurement for the surface passivation of crystalline silicon (c- Si) in heterojunction solar cell. The scatter interval (St) of defect at the a-Si:H/c-Si interface, concentration of micro voids and maxiThe properties of hydrogenated amorphous silicon (a-Si:H) thin layer are studied by spectroscopic ellipsometry (SE) measurement for the surface passivation of crystalline silicon (c- Si) in heterojunction solar cell. The scatter interval (St) of defect at the a-Si:H/c-Si interface, concentration of micro voids and maximum value of dielectric function of a- Si:H layers deposite at different substrate temperatures (Ts) are analyzed by fitting with multilayer mode based on the effective medium approximation. By comprising with the microstructure data calculated from Fourier transform infrared spectroscopy, the correlation between St and the H- bond configurations in a- Si:H layer is obtained. According to the measurement results of transmission electron microscope (TEM), effective minority carrier lifetime and implied open circuit voltage, it is demonstrated that SE technique is an effective characterization tool to estimate the surface passivation quality of a-Si:H for c-Si. Thus, the optimal parameters are quantitatively obtained for the deposition of high quality a-Si:H passivation layer for silicon heterojunction solar cell..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 631002 (2015)
Vision, Color, and Visual Optics
A Spectral Gamut Mapping Model in Visual Features Weighted PCA Space
Liu Pan, Liu Zhen, Zhu Ming, and Wu Guangyuan
In order to solve the inconsistency of device spectral gamut which happens in cross-media spectral color reproduction process, a new spectral gamut mapping model is established in visual features weighted principal component analysity (PCA) space. The standard colorimetric observer matching function is used to construcIn order to solve the inconsistency of device spectral gamut which happens in cross-media spectral color reproduction process, a new spectral gamut mapping model is established in visual features weighted principal component analysity (PCA) space. The standard colorimetric observer matching function is used to construct weight coefficient, which is employed to weight high dimensional spectra. Then the first three components of weighted spectra are extracted by using the PCA method, so that the low dimensional visual features weighted PCA space is set up. In the weighted PCA space, the segment maxima gamut bounduny descriptor algorithm adopted to describe the device spectral gamut, and the outside spectrum is mapped into the device spectral gamut by clipping method. The experimental result indicates that the new model can realize more visual matching than the commonly used method in PCA space, and solve the inconsistency of device spectral gamut more effectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 6, 633001 (2015)
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