Contents
2011
Volume: 31 Issue 3
51 Article(s)
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Atmospheric Optics and Oceanic Optics
Analysis and Design of Fabry-Pérot Etalon of Doppler Wind Lidar
Wang Guocheng, Sun Dongsong, Duan Lianfei, and Shu Zhifeng
Fabry-Pérot etalon is usually employed as discriminating frequency unit in direct detection Doppler wind lidar, and performance of Fabry-Pérot etalon and design of state of incident light beam are important factors in measurement error of the whole systems. The fundamental theory of the Doppler wind lidar basFabry-Pérot etalon is usually employed as discriminating frequency unit in direct detection Doppler wind lidar, and performance of Fabry-Pérot etalon and design of state of incident light beam are important factors in measurement error of the whole systems. The fundamental theory of the Doppler wind lidar based on a triple Fabry-Pérot etalon is introduced. After deep analysis of free spectral range (FSR) and full width at half maximum (FWHM) and peak value interval in two edge channels, the project of parameters design is obtained. The state of incident light beam has an obvious effect on transmission curve of Fabry-Pérot etalon. According to the correlative equation, the effects of incident angle, divergence angle and partial facula permeating through etalon channel designed on transmission curve are provided, and corresponding measurement error is calculated and simulated..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 301001 (2011)
Diffraction and Gratings
Research on Harmonic Wave Separation and Beam Sampling Characteristics of Superposed Volume Bragg Gratings
Zheng Guangwei, Tan Jichun, Shen Benjian, He Yanlan, and Wang Xiao
Superposed volume Bragg gratings (SVBG) has the characteristics of excellent wave vector selectivity and adjustable diffraction efficiency. Based on Kogelnik′s coupled wave theory, the potential applications of SVBG for harmonic-wave separation and beam sampling are analyzed. The results show that the SVBG is made up oSuperposed volume Bragg gratings (SVBG) has the characteristics of excellent wave vector selectivity and adjustable diffraction efficiency. Based on Kogelnik′s coupled wave theory, the potential applications of SVBG for harmonic-wave separation and beam sampling are analyzed. The results show that the SVBG is made up of two pieces of reflecting volume Bragg grating (VBG) and one piece of transmitting VBG. The two pieces of reflecting VBG can highly diffract fundamental frequency and second harmonic beams (harmonic-wave separation ratios are 0.2% and 0.3% respectively), while do little effects on the third harmonic beam (transmittance is up to nearly 100%) in order to make the harmonic-wave separation. The transmitting VBG has low diffraction efficiency for third harmonic beam (only 0.98%). The spatial and temporal intensity distributions of the diffractive beam are similar to those of the third harmonic beam, so the harmonic-wave separation and beam sampling can be realized simultaneously based on the SVBG. The SVBG is a good potential substitution for the traditional grating for the harmonic-wave separation and beam sampling..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 305001 (2011)
Light Modulator by Mask-Phase Method
Kong Ningning, Li Chao, Xia Mingliang, Li Dayu, Qi Yue, and Xuan Li
A Mask-phase method is proposed to calibrate the modulation property of liquid-crystal-spatial light modulator (LC-SLM) at 561 nm, which is calibrated at 532 nm as ex-factory. Firstly, the relation between the phase contrast of the checkerboard phase grating and the intensity of zero-order diffraction spots is simulateA Mask-phase method is proposed to calibrate the modulation property of liquid-crystal-spatial light modulator (LC-SLM) at 561 nm, which is calibrated at 532 nm as ex-factory. Firstly, the relation between the phase contrast of the checkerboard phase grating and the intensity of zero-order diffraction spots is simulated based on Fourier optics. Then the optical path is set up to measure the relation between the gray level and the intensity of zero-order diffraction spots. At last the relation between the gray level and the phase retardation is obtained according to the simulation and experimental results. And the phase-modulation characteristic curve of the LC-SLM at 561 nm is also acquired. After calibration, a spot is modulated by 4λ defocus. In this condition, the intensity distribution deviating from the theoretical value is 45.7, and is reduced by 64.7 compared with 110.4, which is the intensity distribution before calibration. When the spot is modulated by 10λ tilt, the intensities of zero-order and second-order after calibration are reduced to 32.3% and 64.1% respectively, compared to the intensity distribution before calibration. Experimental result indicates that the modulation result of LC-SLM has a great improvement after calibration by the Mask-phase method..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 305002 (2011)
Metal-Coated Long-Period Fiber Grating Liquid Sensor Based on Dual-Peak Resonance
Gu Zhengtian, and Zhang Jiangtao
A novel metal-coated long period fiber grating (LPFG) liquid concentration sensor is presented, which is based on dual-peak resonance combined with high sensitivity of surface plasmon resonance (SPR). On the basis of double-clad structural model and coupled-mode theory of LPFG, the dual-peak resonant characteristics anA novel metal-coated long period fiber grating (LPFG) liquid concentration sensor is presented, which is based on dual-peak resonance combined with high sensitivity of surface plasmon resonance (SPR). On the basis of double-clad structural model and coupled-mode theory of LPFG, the dual-peak resonant characteristics and refractive index sensing properties of metal-coated LPFG are analyzed, and the influence of metal film thickness on sensitivity of dual-peak based LPFG is discussed. Experimentally, the dual-peak resonance-based LPFG with silver film coating has been fabricated, and the salt solution concentration monitoring test was performed. The results show that dual resonant peaks are far away from each other, and shift in opposite directions with increase of salt solution concentrations. The resolution of liquid refractive index is available to 1.8×10-5 for a LPFG with silver film thickness of 103 nm. Furthermore, compared with the dual-peak based non-coated LPFG and general single peak based LPFG, the metal-coated LPFG based on dual-peak resonance has higher refractive index sensitivity..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 305003 (2011)
Fiber Optics and Optical Communications
Experimental Realization of Polarization Multiplexing Differential Phase Shift Keying System Using Only One Demodulator
Xi Lixia, Qin Jiangxin, Zhao Xinyuan, and Zhang Xiaoguang
Polarization multiplexing is one of the effective methods to improve the transmission rate of fiber-optic communication system. A novel configuration polarization multiplexing differential phase shift keying (PolMUX-DPSK) format called dual-polarization differential phase shift keying (DPSK) (Dual-Pol. DPSK) is proposePolarization multiplexing is one of the effective methods to improve the transmission rate of fiber-optic communication system. A novel configuration polarization multiplexing differential phase shift keying (PolMUX-DPSK) format called dual-polarization differential phase shift keying (DPSK) (Dual-Pol. DPSK) is proposed and realized experimentally. It has the same bits symbol ratio with differential quaternary phase shift keying (DQPSK), but it needs a much simpler receiver. Unlike the conventional POLMUX-DPSK, no polarization control or polarization selection is required at the receiver. The polarization-multiplexed symbols are decoded by one Mach-Zehnder delay interferometer (MZDI) and electrical multilevel detection. The tolerances to noise and polarization mode dispersion (PMD) are analyzed and compared with single polarization state DPSK and DQPSK by numerical simulation. The results show that Dual-Pol. DPSK is more sensitive to the noise than DQPSK due to the smaller distance between symbols. For bit error rate (BER) at 10-3, the desired signal-to-noise radio of Dual-Pol. DPSK is 7dB higher than DQPSK. Compared with DPSK, Dual-Pol. DPSK has 5 ps higher PMD tolerance, but its PMD tolerance is lower than DQPSK..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 306001 (2011)
Photonic Approach Using Quadrature Optical Power Ratios for Microwave Frequency Measurement
Zou Xihua, Pan Wei, Luo Bin, Yan Lianshan, and Zheng Di
A photonic approach using two quadrature optical power ratios is proposed to peerform microwave frequency measurement. First, under the carrier-suppression and single-sideband modulation, a microwave signal is applied to modulate a cont; nuous-wave (CW) laser source, leading to the generation of a single sideband., TheA photonic approach using two quadrature optical power ratios is proposed to peerform microwave frequency measurement. First, under the carrier-suppression and single-sideband modulation, a microwave signal is applied to modulate a cont; nuous-wave (CW) laser source, leading to the generation of a single sideband., Then optical comb filters are adopted to process the sideband and two optical powers presenting sine-form and cosine-form distributions are detected as the microwave frequency increases. After comparing the two optical powers to the reference power, two optical power ratios of sine-form and cosine-form are obtained, namely quadurature optical power ratios. Based on the two optical ratios, the frequency is unambiguously estimated within the full free spectral range (FSR) of the comb filtering responses. Two setups are designed to verify the proposed approach, one consisting of two laser sources and a single comb filter, and the other including a single laser source and two comb filters. The latter setup is experimentally demonstrated. Compared with other reported approach, the proposed approach provides a larger measurement range and a promising way to design cascaded or parallel configurations..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 306002 (2011)
Characteristic Research and Detection Scheme of Gigabit Passive Optical Network Upstream Optical Signal
Guo Yamin, Zhang Xuping, Xie Fei, Zhang Yixin, and Wang Shun
It is difficult to realize real-time power detection as the upstream signal of gigabit passive optical network(GPON) system is high-speed burst mode. Based on the analysis of the upstream signal transmission characteristics, the frame overhead, and the noise model, a new detection method is presented. This method raiseIt is difficult to realize real-time power detection as the upstream signal of gigabit passive optical network(GPON) system is high-speed burst mode. Based on the analysis of the upstream signal transmission characteristics, the frame overhead, and the noise model, a new detection method is presented. This method raises the signal to the original system with pre-through high-impedance amplifier, which does not affect the performance of the original system. High-frequency burst signal will be down converted for processing, through the peak detecting and low-pass filtering. A limiting amplifier and digital decision device of low-level optical receiver module can be used to correct the error after the signal′s average power is obtained. Since the method can improve the signal-to-noise ratio, and make full use of system function to obtain information of the duty ratio, it is low-cost and has high detection accuracy. The experimental result has shown that the method is quite suitable for GPON system upstream signal power detection..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 306003 (2011)
Characterization of Polarization Dependent Loss in Reflection in Uniform Fiber Bragg Gratings
Gao Shecheng, and Li Qianghua
Wavelength dependency of polarization dependent loss (PDL) in reflection in uniform fiber Bragg gratings (FBG) written in single-mode fibers (SMF) is studied deteriledly. Effective PDL (PDLeff) and simulations are carried out using the coupled-mode theory and the Jones matrix. The evolution with wavelength of PDLeff asWavelength dependency of polarization dependent loss (PDL) in reflection in uniform fiber Bragg gratings (FBG) written in single-mode fibers (SMF) is studied deteriledly. Effective PDL (PDLeff) and simulations are carried out using the coupled-mode theory and the Jones matrix. The evolution with wavelength of PDLeff as a function of the grating parameters and the birefringence value is analyzed. The PDLeff appears clearly on the band edges of the reflection spectrum, especially with the steep sides. Numerical results demonstrate that the PDLeff evolutions with wavelength can be strongly enhanced by a modification of the grating parameters. With increase of grating length and modulation depth, the PDLeff rapidly increases. For a given grating length and modulation depth of the grating, when grating birefringence is less than 2×10-5, the PDLeff increases rapidly with the increase of birefringence. As birefringence is greater than 2.5×10-4, the two main peaks with sub-peaks on it of the PDLeff become greater. With birefringence continuing increasing, the distance between the two main peaks increases, and the sub-peaks on the main peaks become smaller. They are presented a complete characterization of PDLeff in FBG and a good agreement between theory and experiment is got..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 306004 (2011)
Optical Cross Connection: Novel Architecture and Performance Analysis
Le Zichun, Chen Jun, Fu Minglei, Zhu Zhijun, Hou Jibin, and Zhang Ming
A novel optical cross connection named limited wavelength conversion wavelength interchangeable cross connection (L-WIXC) is proposed to improve the conflict resolution and decrease the cost. The optical architecture and network control system of L-WIXC as well as corresponding control algorithm are described. By meansA novel optical cross connection named limited wavelength conversion wavelength interchangeable cross connection (L-WIXC) is proposed to improve the conflict resolution and decrease the cost. The optical architecture and network control system of L-WIXC as well as corresponding control algorithm are described. By means of comparing congestion properties of several different OXC structures and different signaling protocols, it can be concluded that the congestion of L-WIXC is lower, and L-WIXC with JET protocol has better congestion probability than that with JIT protocol. A simulation platform is also built for testing the performance of L-WIXC. The tests are done and analyzed for single L-WIXC node, serial links with L-WIXC and mesh links with L-WIXC by simulating the optical power, crosstalk, BER and eye diagram. The results show that L-WIXC has satisfying performance for applying in optical switching networks, especially in optical burst switching network..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 306005 (2011)
Image Processing
Background Clutter Quantification Method for Infrared Image of Small Targets
Huang Kang, Mao Xia, and Liang Xiaogeng
By analyzing the influence of background clutter on infrared small targets detection, we have researched a background clutter description method for infrared images of small targets. Three conditions of a background clutter description method are proposed: consistent with subjective judgment; suituble for different infBy analyzing the influence of background clutter on infrared small targets detection, we have researched a background clutter description method for infrared images of small targets. Three conditions of a background clutter description method are proposed: consistent with subjective judgment; suituble for different infrared images; assistant with improvement of target detection algorithms. Four features are synthesized by considering the relation between targets and backgrounds, and a novel method is proposed for describing the background clutter quantitatively in infrared images of small targets. Firstly, supporting vector machine is emploged to classify the backgrounds. Secondly, the weight of each feature is calculated by analytic hierarchic process for each class of background images. Then the quantification problem is solved. Compared with the conventional methods, the validity of the proposed method has been demonstrated by the experimental results..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 310001 (2011)
Method for Phase Recovery from a Single Undersampled Wrapped Phase Map
Fan Qi, Yang Hongru, Li Gaoping, Yuan Liang, Jiang Changlu, and Guo Yu
Aiming at the problem of undersampling in the aspheric testing, a method for phase recovery from a single undersampled wrapped phase map is presented. Firstly, two wrapped phase differences are gained by subtracting the original undersampled wrapped phase with its two sheared copies along two orthogonal directions whilAiming at the problem of undersampling in the aspheric testing, a method for phase recovery from a single undersampled wrapped phase map is presented. Firstly, two wrapped phase differences are gained by subtracting the original undersampled wrapped phase with its two sheared copies along two orthogonal directions while the sheared value is 1 pixel. Secondly, the unwrapping is performed for the two wrapped phase differences. Finally, the searched phase is obtained by using the Fourier transform and least square algorithm. The simulation results show that the method can retrieve the wave-front with high accuracy. Using the method, the aspheric surface can be tested by current interferometers..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 310002 (2011)
Imaging Systems
Experimental Research of Fourier Telescopy Imaging System
Chen Wei, Li Quan, and Wang Yangui
Fourier telescopy (FT) is a high-resolution optical interference imaging method which is mainly used for distant and very dim objects. Being illuminated by several spatial diversed and frequency-encoded laser beams, object will reflect the light as a temporal series signal which contains the information of the target′sFourier telescopy (FT) is a high-resolution optical interference imaging method which is mainly used for distant and very dim objects. Being illuminated by several spatial diversed and frequency-encoded laser beams, object will reflect the light as a temporal series signal which contains the information of the target′s spatial spectrum. After the signal is demodulated, the target′s spectrum will be recovered with the help of the phase-closure algorithm by which the random atmospheric phase errors will be cancelled out, and then, the image can be reconstructed by inverse Fourier transform. An experimental scheme based on diverging light has been put forward to verify the feasibility of this imaging technology, and both of one- and two-dimensional objects have been reconstructed successfully in laboratory. Besides, several useful references for building field′s FT system can be offered by this scheme. Firstly, it simulates the T-shape configuration properly, which is helpful to study the field transmitter array while the field′s requirement is not mature. Secondly, the scheme is based on diverging light to illuminate the target, It not only approaches the practical situation, but also makes the laser faculae overlap together on target′s surface all the time which is good at improving the signal-to-noise ratio of the reflected signal because the energy of the light is used at utmost. And it will be beneficial to aim the target and to avoid the atmospheric turbulence in system design..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 311001 (2011)
Projection Decomposition Algorithm of X-Ray Dual-Energy Computed Tomography Based on Projection Matching
Li Baolei, and Zhang Yaojun
X-ray dual-energy computed tomography imaging technique is an important material detection and recognition method in the field of security inspection. The projection decomposition is the nuclear content and key technique in the pre-reconstruction algorithm of dual-energy computed tomography. According to the disadvantaX-ray dual-energy computed tomography imaging technique is an important material detection and recognition method in the field of security inspection. The projection decomposition is the nuclear content and key technique in the pre-reconstruction algorithm of dual-energy computed tomography. According to the disadvantages of the current algorithms, a projection decomposition algorithm based on projection matching is proposed. Firstly, based on energy spectrum of the system and the linear attenuation coefficient curve of the basic materials, the high-and low-energy projection lookup table can be got by solving the projection integral equations set. For a given dual-energy projection, find the best match point in the lookup table and then obtain the decomposition projection of basic materials. The proposed algorithm avoids the process of complex iteration and optimization and simplifies the process of system calibration. The decomposition accuracy depends on the step setting of lookup table. Compared to the current algorithms, the proposed algorithm′s realization is more simple and easy for parallel computation. The feasibility of the algorithm is validated by the results of simulation experiment..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 311002 (2011)
Axial Focal Shift and Extended Focal Depth with Tunable Filter
Yun Maojin, Wang Mei, Kong Weijin, Liu Liren, Liang Jian, Zhu Huafeng, and Gao Xiumin
Optical superresolution, focal shift and high focal depth in optical imaging system have been the goal of many researchers and have widely application in the optical microscopy, optical alignment and optical coherent tomography systems. A tunable pupil filter for modulation of axial focal shift and extended focal depthOptical superresolution, focal shift and high focal depth in optical imaging system have been the goal of many researchers and have widely application in the optical microscopy, optical alignment and optical coherent tomography systems. A tunable pupil filter for modulation of axial focal shift and extended focal depth is proposed. It consists of one half-wave plate located between two identical and parallel quarter wave-plates, the half-wave plate is made up of two zones that can rotate with respect to each other, and the pupil function is deduced. The research result shows that with the designed pupil filter the axial focal shift can be controlled by rotating the half-wave plate. So the designed tunable pupil filter can be utilized in automatic focusing applications that are similar to optical read-write drives for which is necessary to track the focal plane dymamically. Furthermore, when the phase difference is π, the transverse superresolution and axially extended focal depth can be realized at the same time. And it can be used in optical confocal scan imaging system..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 311003 (2011)
Instrumentation, Measurement and Metrology
Mono Camera and Laser Rangefinding Sensor Position-Pose Measurement System
Chao Zhichao, Fu Sihua, Jiang Guangwen, and Yu Qifeng
Precision of translation measurements along the camera′s optical axis is generally much lower than that of which is perpendicular to the optical axis in monocular vision measurement due to the inherent limitation of the system. First of all, mathematical model is analyzed to explain the cause, then a high-precision lasPrecision of translation measurements along the camera′s optical axis is generally much lower than that of which is perpendicular to the optical axis in monocular vision measurement due to the inherent limitation of the system. First of all, mathematical model is analyzed to explain the cause, then a high-precision laser rangefinding sensor (DLS) is installed near the camera to construct the Monoocular Camera-DLS pose measurement system, which will improve the precision of translation measurements along the optical axis with DLS measurements; Finally, principle of the system′s calibration and data fusion method are conducted. Experimental results show the feasibility and validity of the position-pose measurement system..
Acta Optica Sinica
- Publication Date: Aug. 13, 2021
- Vol. 31, Issue 3, 312001 (2011)
Ionization Effect in the Transparent Window for Shock-Wave Diagnosis under Indirect Drive
Wang Feng, Peng Xiaoshi, Liu Shenye, Jiang Xiaohua, and Ding Yongkun
When the shock wave is diagnosed under indirect drive, the ionization effect caused by the X-ray in the Al2O3 and quartz has been explained with semiconductor model. And the model explanation has been confirmed by the experimental data. In the experimental data, the signal modulation in quartz on time scale has been coWhen the shock wave is diagnosed under indirect drive, the ionization effect caused by the X-ray in the Al2O3 and quartz has been explained with semiconductor model. And the model explanation has been confirmed by the experimental data. In the experimental data, the signal modulation in quartz on time scale has been confirmed with photo-carrier model. It is found that there is not clear “blank” effect in the quartz even if the radiation temperature is 180 eV with 60 μm ablation. The “blank” effect can be avoided obviously after the Au is used as the blocking layer. And this method provides the diagnosis way for shock wave under indirect drive..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 312002 (2011)
Intensity-Modulated Surface Plasmon Resonance Array Sensor Based on Polarization Control
Sun Boshu, Huang Zihao, Wang Xiaoping, Liu Yuling, and Liu Xu
Intensity-modulated surface plasmon resonance (SPR) array sensor based on polarization control is introduced. The influence of incident angle, gold firm thickness, polarizer angle, wavelength and data processing on its sensitivity and measuring range is analyzed and sensor systems with wavelength set at 632.8 nm and 74Intensity-modulated surface plasmon resonance (SPR) array sensor based on polarization control is introduced. The influence of incident angle, gold firm thickness, polarizer angle, wavelength and data processing on its sensitivity and measuring range is analyzed and sensor systems with wavelength set at 632.8 nm and 740 nm are experimentally studied. It is concluded that intensity-modulated SPR array sensor turns the polarization state change of light wave during the excitation of surface plasmons into intensity change to detect in an easily controllable measurement range. Using an appropriate parameter selection, high sensitivity can be produced with a simple optical and mechanical structure and lower production costs. This scheme can be widely applied to the high-throughput detections of bimolecular interaction analysis, environmental monitoring, food safety, pharmaceutical analysis, biomedical engineering and other fields..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 312003 (2011)
Vision Inspection of Metal Surface Defects Based on Infrared Imaging
Zhang Xuewu, Ding Yanqiong, and Yan Ping
According to the characteristics of infrared imaging and the gradual change of intensity levels of metal surface defects, a vision inspection method for surface defects of metal based on statistically analyzing wavelet texture has been proposed. Firstly, the CCD sensors are used to obtain infrared video-data for surfacAccording to the characteristics of infrared imaging and the gradual change of intensity levels of metal surface defects, a vision inspection method for surface defects of metal based on statistically analyzing wavelet texture has been proposed. Firstly, the CCD sensors are used to obtain infrared video-data for surface of copper strips, and then the first-order Haar wavelet is used to decompose infrared image. Secondly, two multivariate statistical methods, including Hotelling T2 control chart and Chi square test, are used to fuse the four wavelet characteristics. Finally, the statistical values are used to distinguish the existence of defects and classify the defects using support vector machine. The capabilities of two kinds of wavelet-domain-based multivariate statistical approaches in inspecting defects have been researched deeply. The experimental results demonstrate that the Hotelling T2 method gets the better performance, which achieves a 92.8% probability of detecting the existence of micro defects and a 95.42% probability of classifying the defects..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 312004 (2011)
Application and Research of Composite Autofocusing Technique in Optical-Lens Measurement
Zhang Zhenjiu, Hu Hong, and Li Tianli
A composite autofocusing technique consisting of coarse autofocusing and fine autofocusing is proposed for test system of optical-lens parameter. In the coarse autofocusing procedure, variance function achieved from the whole image is selected as sharpness evaluation function, mean comparison method is applied to realiA composite autofocusing technique consisting of coarse autofocusing and fine autofocusing is proposed for test system of optical-lens parameter. In the coarse autofocusing procedure, variance function achieved from the whole image is selected as sharpness evaluation function, mean comparison method is applied to realize the hill-climbing algorithm for focal plane searching, and a 3-point method is used to initialize the searching direction. In the fine autofocusing procedure, a conditional dilation method based on mathematical morphology and a shape factor are employed to extract the connected regions, namely, the target images. Brenner function within the target image is selected as the sharpness evaluation function, and the hill-climbing algorithm with single-point comparison is used to find the focal plane accurately. The experiments validate that the composite autofocusing technique possesses not only high accuracy but also large autofocusing range. It can guarantee that the focusing position locates in the depth of field of the camera lens and the lens parameter measuring results possess good accuracy and repeatability..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 312005 (2011)
3D Auto-Inspection for Large Thin-Wall Object
Liu Xiaoli, Peng Xiang, Yin Yongkai, Li Ameng, Zhang Chenggong, and He Dong
We propose an optical measurement technique devoted to on-line inspection of large-scale and thin-wall objects. The proposed approach is based on a measurement network that consists of three-node optical sensors. With this specifically designed measurement network system, we can achieve the inspection tasks such as mulWe propose an optical measurement technique devoted to on-line inspection of large-scale and thin-wall objects. The proposed approach is based on a measurement network that consists of three-node optical sensors. With this specifically designed measurement network system, we can achieve the inspection tasks such as multi-view range-data acquisition, registration, and integration while it is also possible to make a comparison of reconstructed model with the computer-aided-design (CAD) model to precisely determine the error distribution on each external and internal facet walls. An on-line calibration scheme for multiple-node sensors based on phase-mapping combined with photogrammetric technique is also presented and verified by experiments. Furthermore, the registration of multi-view range-data can be achieved using the calibrated parameters and iterative closest points (ICP) algorithm. Moreover, we also employ ICP algorithm for the alignment of reconstructed model with measured data with the nominal CAD model, and then the dimension computation and error comparison can be easily acquired. Both the theoretical analysis and the experimental results show the effectiveness of the proposed approach..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 312006 (2011)
Optical 3D Deformation Measurement System and its Application to Investigation of Mechanical Behaviors of Micro-Structure
Shi Hongjian, Ji Hongwei, and He Xiaoyuan
An optical measurement system for simultaneous 3D surface profile and deformation measurement of micro-components is presented by using microscopic fringe projection and digital-image correlation technique. In the system, sinusoidal fringes are projected on the surface of the specimen by a grating phase shifting projecAn optical measurement system for simultaneous 3D surface profile and deformation measurement of micro-components is presented by using microscopic fringe projection and digital-image correlation technique. In the system, sinusoidal fringes are projected on the surface of the specimen by a grating phase shifting projector. The deformed fringe patterns are captured by a high-resolution CCD camera and a microscope. The images are processed with phase-shifting technique. The intensity of the specimen′s background before and after deformation obtained by adding the phase-shifting images are processed by digital-image correlation technique. This system will be useful for optical measurement of micro-structure. As an application, the system is used to investigate the mechanical behaviors of molded pulp material in micro-zone during tension testing..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 312007 (2011)
A Method of Phase Error Compensation for Structural Light Measurement
Xu Wei, Chen Xiaobo, and Xi Juntong
Based on simulation of the influence of gamma nonlinearity of the projector on phase error, a method of phase error compensation for structural light measurement based on phase shifting is put forward. In this method, quadratic polynomial is used to approximate the intensity of the captured images, meanwhile least squaBased on simulation of the influence of gamma nonlinearity of the projector on phase error, a method of phase error compensation for structural light measurement based on phase shifting is put forward. In this method, quadratic polynomial is used to approximate the intensity of the captured images, meanwhile least square fitting method is used to compensate the phase error, and in this way, system error caused by the gamma nonlinearity of the projector is reduced greatly. Because it doesn′t depend on environmental light, camera parameters or DLP parameters, this method has superiority in aspects of universality, complexity and calculation speed. Experimental results show that this method reduces greatly the phase error caused by the gamma nonlinearity of the projector. The average phase error is 5 times smaller than that before error compensation, meanwhile the bit error rate of unwrapping based on look-up table method is reduced 14.5 times..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 312008 (2011)
Integrated Optics
Theoretical Analysis of Propagation Loss of Rib Waveguide
Wen Changli, Ji Jiarong, Dou Wenhua, Feng Xianghua, and Song Yansheng
Vertical cavity surface emitting laser (VCSEL) is widely used in the interconnection of new-generation computer, which is a multi-mode laser with the wavelength at 850 nm. A rib waveguide with section area similar to the output plane needs to be developed to fit VCSEL better. Based on the successful preparation of polyVertical cavity surface emitting laser (VCSEL) is widely used in the interconnection of new-generation computer, which is a multi-mode laser with the wavelength at 850 nm. A rib waveguide with section area similar to the output plane needs to be developed to fit VCSEL better. Based on the successful preparation of polysiloxane rib waveguide, which has the smallest area of 70 μm×50 μm and straight length of 21 cm, theoretical analysis of its loss mechanism is processed. By using perturbation theory, it is concluded that the absorption of material can be neglected and the main loss of scattering comes from the loss of surface scattering induced by the roughness of top surface, bottom surface and side surface. By using variational principle and finite element method, the field distribution influenced by bubble, defect and impurity is analyzed. Concrete measured value of bubble, defect and impurity at saltus, visible influence of basic mode and first-order mode is gotten. Transmission loss measured by CCD photography shows that experimental results fit the theoretical results well..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 313001 (2011)
Lasers and Laser Optics
Interferometry for Absolute Distance Measurement
Li Zhidong, Jiang Yuesong, Sang Feng, Wang Linchun, Deng Shiguang, Xin Yao, and Guo Jingping
Target movements can introduce movement error in absolute distance measurement using frequency-scanning interferometry. It is deduced that movement error depends on the optical path difference displacements during the scan and the laser frequency at the endpoint of the scan. The former can be obtained directly by usingTarget movements can introduce movement error in absolute distance measurement using frequency-scanning interferometry. It is deduced that movement error depends on the optical path difference displacements during the scan and the laser frequency at the endpoint of the scan. The former can be obtained directly by using a high-accuracy wave meter; for the latter, heterodyne interference frequency division multiplexing technique is proposed and a novel frequency-scanning interferometer for absolute distance is designed to achieve simultaneous measurement of the absolute distance and the optical path difference displacements. Movement error-compensation can be fulfilled by eliminating the error phase offset related to laser frequency at the endpoint of the scan and the optical path difference displacements. Theoretical analysis of the feasibility of the system and the uncertainty of movement compensation with precision measurement simulation indicate that the compensation method is efficient and effective. Optical path difference displacements measurement can reach nanometer level for rather high-speed target. The error introduced by movement compensation is tens of microns with the frequency-scanning range of 100 GHz at tens of meters distance range..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 314001 (2011)
Research on Cavity-Dumping Mode-Locked Laser of Picosecond at 10 kHz
Fu Jie, Pang Qingsheng, Chang Liang, Ai Qingkang, Chen Liyuan, Chen Meng, Li Gang, Ma Yunfeng, Fan Zhongwei, Niu Gang, Yu Jin, Liu Yang, Zhang Xue, Kang Wenyun, and He Kai
Mode locked and cavity dumping techniques are comtined to get picosecond pulse with high energy at high repetition rate. The mechanism and physical image of cavity-dumping mode-locked laser are analyzed and factors which affect the dumping efficiency of cavity-dumping laser are studied. Cavity-dumping mode-locked laserMode locked and cavity dumping techniques are comtined to get picosecond pulse with high energy at high repetition rate. The mechanism and physical image of cavity-dumping mode-locked laser are analyzed and factors which affect the dumping efficiency of cavity-dumping laser are studied. Cavity-dumping mode-locked laser at repetition rate of 10 kHz can be realized with the help of NdYVO4 SESAM mode-locking and a BBO modulator placed in cavity. When pump power is 14.1 W, pulses with energy of 6.5 μJ are obtained, and the pulse width is about 10.4 ps. This kind of laser will have good prospects for development because high energy pulses can be obtained directly from mode-locked oscillator..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 314002 (2011)
Adaptive Near-Field Beam Shaping Based on Simulated Annealing Algorithm
Yu Zhan, Ma Haotong, and Du Shaojun
In practical applications, it is always necessary to convert the intensity distributions of the laser beams into desired profiles for improving the efficiency. Based on the high spatial resolution and programmable controller of the phase-only liquid crystal spatial light modulator, an adaptive near-field beam shaping sIn practical applications, it is always necessary to convert the intensity distributions of the laser beams into desired profiles for improving the efficiency. Based on the high spatial resolution and programmable controller of the phase-only liquid crystal spatial light modulator, an adaptive near-field beam shaping system composed of simulated annealing algorithm is built. The feasibility of the system is validated by translating an ideal Gaussian beam into a flattop beam in the near field theoretically. Finally, the experimental closed control loop system is built to convert a quasi-Gaussian beam emitting from a solid laser into a quasi-flattop beam in the near field. The experimental results show that 64% energy of the actual output beam concentrates in a region which has a relative root mean square (RMS) intensity variation less than 9%..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 314003 (2011)
Materials
Luminescent Properties of Red Phosphors Prepared by Sol-Gel and Microwave Radiation Methods
Li Yali, Wang Chaonan, Song Guohua, and Ji Xianming
Sol-gel and microwave radiation methods are used to synthesize red phosphors of Mg2:SiO4 doped with Mn2+ and Dy3+. The effect of the concentration of Mn2+ and the microwave synthesis time on luminescence spectra is investigated. In the co-doped samples, the influence of concentration of Dy3+ on luminescence spectra is Sol-gel and microwave radiation methods are used to synthesize red phosphors of Mg2:SiO4 doped with Mn2+ and Dy3+. The effect of the concentration of Mn2+ and the microwave synthesis time on luminescence spectra is investigated. In the co-doped samples, the influence of concentration of Dy3+ on luminescence spectra is also investigated. The red color phosphors of Mn2+, Dy3+Mg2:SiO4, which can be excited effectively under 410 nm radiation, are obtained by means of these two methods. The samples show a red emission peaked at 690 nm..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 316001 (2011)
Preparation and Spectra of CdSe-Quantum-Dot-Doped PMMA Fiber Materials
Cheng Cheng, Wang Sunde, and Ma Dewei
Plastic fiber has advantages over the conventional quartz fiber on respect of cost, fiber to the home application and short-distance communications. The plastic fiber amplifier can be gotten by doping the optical gain media such as quantum dots (QD) into plastic fiber. However, there is few study reported on the QD-dopPlastic fiber has advantages over the conventional quartz fiber on respect of cost, fiber to the home application and short-distance communications. The plastic fiber amplifier can be gotten by doping the optical gain media such as quantum dots (QD) into plastic fiber. However, there is few study reported on the QD-doped plastic fiber. CdSe QD doped PMMA fiber material (CdSe/PMMA) is prepared. The UV-vis-near-infrared spectrum shows a narrow-size distribution of the CdSe QD in the CdSe/PMMA. The photoluminescence (PL) spectrum of the CdSe/PMMA is widen (about 10 nm) compared with the plain CdSe QD. Irradiated by a 473 nm laser for about 12 h, the PL peak intensity of the CdSe/PMMA is enhanced (about 1 time), and the peak wavelength shows a blue shift with 25 nm. Obtained results suggest that the CdSe/PMMA may be available fiber materials used as broadband amplifiers in the future..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 316002 (2011)
Study on Characteristics of Quasi-Fractal Photonic Crystal Based on Sierpinski Gasket Structure
Liu Lingyu, Tian Huiping, Xu Pan, and Ji Yuefeng
The Sierpinski gasket structure is introduced into two-dimensional photonic crystal to design a new kind of photonic crystal——the Sierpinski quasi-fractal photonic crystal. By using finite-difference time-domain method, the transmission spectra of Sierpinski quasi-fractal photonic crystal with dielectric rods and air hThe Sierpinski gasket structure is introduced into two-dimensional photonic crystal to design a new kind of photonic crystal——the Sierpinski quasi-fractal photonic crystal. By using finite-difference time-domain method, the transmission spectra of Sierpinski quasi-fractal photonic crystal with dielectric rods and air holes are calculated and analyzed respectively. The results show that the band gap exists on the condition of dielectric rods and incidence of TM wave only. The band gap property(bandwidth and central frequency) and characteristics of the pass-bands which exist in the band gap of Sierpinski circular-rods quasi-fractal photonic crystal with different dielectric constant and fill ratio are analyzed. Further more, the effects of different fractal series and dielectric-rod shapes on the transmission spectra and band-gap characterishis are simulated..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 316003 (2011)
Temperature Properties of Fluorescence Spectra in Tm3+-Doped LaOF and SiO2 Nanosystems
Zhang Xisheng, Yan Chunyu, Yao Chenzhong, and Zheng Hairong
Fluorescence spectra of Tm3+-doped LaOF and SiO2 nanosystems at different temperatures are investigated, which show that line width, intensity of fluorescence and spectra position all change with the increase of temperature in the range of 20~300 K. Dependency on temperature of fluorescence spectra is influenced directFluorescence spectra of Tm3+-doped LaOF and SiO2 nanosystems at different temperatures are investigated, which show that line width, intensity of fluorescence and spectra position all change with the increase of temperature in the range of 20~300 K. Dependency on temperature of fluorescence spectra is influenced directly by local environment. Fluorescence lifetime of active ions in SiO2 uncrystal phase is less affected, while it is largely affected in LaOF crystal phase ambient. The rule reliance upon temperature of 3H4 lifetime is studied under pulsed laser excitation..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 316004 (2011)
Medical Optics and Biotechnology
Visible-Infrared Reflectance Spectroscopy Applied in Rapid Screen of Diseases
Li Gang, Zhao Jing, Li Jiaxing, Lin Ling, and Zhang Baoju
To screen disease which based on tongue inspection rapidly, the reflection spectrum on the tongue tips of 149 volunteers were collected by visible and near-infrared spectrometer and then the normalized reflectivity was calculated. Samples were divided into four classes according to the clinical diagnosis information: hTo screen disease which based on tongue inspection rapidly, the reflection spectrum on the tongue tips of 149 volunteers were collected by visible and near-infrared spectrometer and then the normalized reflectivity was calculated. Samples were divided into four classes according to the clinical diagnosis information: healthy, hyperviscosity, fatty liver, and coronary heart disease groups. Spectra were then subjected to three different analysis methods: principle component analysis (PCA) combined with artificial neural network (ANN), partial least squares (PLS), and interval PLS (iPLS). The classification accuracy of each model are 75%, 75%, and 85%, respectively. The results show that iPLS method sees more robust than the others. And the results also show that near-infrared region including more disease information than visible region. Experimental results show that the application of the spectra for disease diagnosis is promising..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 31, Issue 3, 317001 (2011)
Influence of Real Forearm Structure on Light Transport Based on MCVM
Wang Anle, Li Ting, Deng Yong, Xie Tianwu, Liu Qian, and Luo Qingming
Accurate simulation of light propagation in complicated biological tissues has been a research focus of tissue optics. By utilizing the latest published Monte Carlo software-Monte Carlo modeling of photon migration in voxelized media(MCVM), with the human structure database of the highest resolution in the world. It isAccurate simulation of light propagation in complicated biological tissues has been a research focus of tissue optics. By utilizing the latest published Monte Carlo software-Monte Carlo modeling of photon migration in voxelized media(MCVM), with the human structure database of the highest resolution in the world. It is obtained the distribution of the absorption in the forearm and the effect on light transport and distribution. The results indicated that the three-dimensional anatomic structrue influences the light transport and distribution obviously, and the simulation results were much closer to the real state by comparing with the results obtained previously by MCML (the Monte Carlo Modeling of light transport in multi-layered tissues) and layered tissue model. So the analysis provide the guidance to optical health care techniques, such as photodynamic therary and infrared therapy..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 317002 (2011)
Statistical Characterization on Refractive-Index Fluctuations of One-Dimensional Light Propagating Medium
Tao Yuanhao, Ding Zhihua, Fu Jian, and Yang Liu
A method based on reflective mesoscopic spectroscopy for characterization of refractive-index fluctuations at nano-scale is introduced. Mechanism of mesoscopic spectroscopy for perceiving reflective-index fluctuations at length scale of nanometers is revealed. Based on simulation by finite difference time domain methodA method based on reflective mesoscopic spectroscopy for characterization of refractive-index fluctuations at nano-scale is introduced. Mechanism of mesoscopic spectroscopy for perceiving reflective-index fluctuations at length scale of nanometers is revealed. Based on simulation by finite difference time domain method, light propagation in one-dimensional refractive-index variable medium and resulting reflective spectral characteristics are analyzed. Through precise control of standard deviation and spatial correlation length of refractive-index fluctuations along one-dimensional channel, simulated disorder strengths and their relation to theoretical settings are quantitatively analyzed. Results show that reflective spectrum is highly sensitive to disorder strength and thus it is feasible for the refractive index fluctuations at nano-scale within one-dimensional channel to be perceived through reflective spectrum. Under certain approximating conditions, disorder strength is proportionally enlarged with increasing variance and spatial correlation length describing refractive-index fluctuations. The proposed method might be useful in probing statistical structural changes at nano-scale which are unperceivable up to now, and hence avoiding the limitation due to optical diffraction in far field..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 317003 (2011)
Effect of Gold Nanoparticles on Tissue Optical Properties of Gastric Tumor Tissue in Near-Infrared Spectral in Nude Mice
Kong Meng, Zeng Changchun, Xiong Honglian, Liu Hanping, and Liu Songhao
In order to detect the effect of gold nanoparticles on gastric tumor tissue in near-infrared optical imaging, the spectral feature in near-infrared is observed after gold nanoparticles piled up in tumor tissues of gastric as a contrast agent. The MCG-803 human gastric cancer cell line (from CTCC) is subcutaneously inocIn order to detect the effect of gold nanoparticles on gastric tumor tissue in near-infrared optical imaging, the spectral feature in near-infrared is observed after gold nanoparticles piled up in tumor tissues of gastric as a contrast agent. The MCG-803 human gastric cancer cell line (from CTCC) is subcutaneously inoculated in BALB/C nude mice, and then the orthotopic graft model of gastric cancer is made. Animals are divided into two groups: gastric tumor tissue control group and gastric tumor tissue with gold nanoparticles group. The optical attenuation coefficients of tumor tissue are detected by a near-infrared spectroscopy. The results show that the shape of the transmittance spectra of tumor tissues with gold nanoparticles and tumor tissues without gold nanoparticles is similar in near-infrared range from 800 to 1500 nm. But the spectral transmittance is slightly lower than that of the corresponding tumor tissue about 4.4% to 7.0%. And there are significant differences at the statistical sites of 900, 1000, 1100, 1200, 1300 and 1400 nm. The present study has suggested that gold nanoparticles accumulated in nude mice gastric cancer can affect on optical properties tumor of tissue, which can provide a theoretical guidance for the optical imaging detection of tumor tissue..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 317004 (2011)
Microscopy
Optimization of 0/π Phase Plate in Stimulated Emission Depletion Microscopy
Hao Xiang, Kuang Cuifang, Wang Tingting, and Liu Xu
By use of vectorial diffraction theory, intensity distribution around focal spot of stimulated emission depletion (STED) beam in STED microscopy is numerically calculated and influence of diverse 0/π circular phase plate to performance of focal spot is evaluated. It is demonstrated that dark spot in center of focal plaBy use of vectorial diffraction theory, intensity distribution around focal spot of stimulated emission depletion (STED) beam in STED microscopy is numerically calculated and influence of diverse 0/π circular phase plate to performance of focal spot is evaluated. It is demonstrated that dark spot in center of focal plane can never be expected unless proper parameter of phase plate is selected, while such parameters are diverse with various polarizations and beam shapes of incident beams. Furthermore, effect of numerical aperture is comparatively neglectable. Explicit calculation further presents that reasonable value ranges of the inner radii of the phase plate are almost the same if the STED beam is linearly or circularly polarized, which is smaller than that of system with a radially polarized incidenct beam and the beam with azimuthal polarization can never be the proper option for STED beam..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 318001 (2011)
Investigation of the Ultraviolet-Visible Micro-Fluorescence-Spectra and Chromaticity of Single Oil Inclusion
Yang Ailing, Tang Mingming, Ren Weiwei, Yang Yun, and Zhang Jinliang
An experimental setup is established for measuring ultraviolet-visible(UV-VIS) micro-fluorescence-spectra of single oil inclusion by integrating elements, such as inverted microscope, reflecting microscopic objective, micro-lens, fiber and spectrometer. Any rebuilding to the microscope is not needed to be done. The UV-An experimental setup is established for measuring ultraviolet-visible(UV-VIS) micro-fluorescence-spectra of single oil inclusion by integrating elements, such as inverted microscope, reflecting microscopic objective, micro-lens, fiber and spectrometer. Any rebuilding to the microscope is not needed to be done. The UV-VIS spectra of single oil inclusion of Fu 4 well（Quan 3 stratum, Jilin oil field）are measured. By fluorescence spectra excited at 250 nm, the main aromatic hydrocarbon composites of the paleo-oil are qualitatively determined. The results show that the relatively heavy hydrocarbons in liquid oil inclusions are more than that in the gas-liquid inclusions. By fluorescence spectra excited at 365 nm, the chromaticity diagram of the oil inclusions are calculated, which overcomes the subjectivity of judging the colors by human eyes. The UV-VIS spectra and chromaticity diagram of the single oil inclusion from same stratum show that there maybe two maternal sources of different maturities when the secondary oil charges..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 318002 (2011)
Nonlinear Optics
Exploration of Temperature, Power and Polarization Dependence of Four-Wave Mixing in EIT Window
Miao Yizhu, Cheng Xuemei, Ren Zhaoyu, Wang Zhaojin, and Bai Jintao
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 319001 (2011)
Optical Design and Fabrication
Modelling of Offner Imaging Spectrometers and Aberration Analysis
Liu Guanghong, Wu Gang, Ling Qing, Wang Qiuping, and Du Xuewei
The ray-tracing method is applied to get the numerical model of the system, and then a series expansion method is used to establish a three-order analytical model. The analytical model provides analytical expressions of aberration coefficients and spot diagrams, adapts to the system containing a varied line spacing conThe ray-tracing method is applied to get the numerical model of the system, and then a series expansion method is used to establish a three-order analytical model. The analytical model provides analytical expressions of aberration coefficients and spot diagrams, adapts to the system containing a varied line spacing convex grating, and has strong scalability. The complete imaging performance can be quickly evaluated by the analytical expressions of spot diagrams. By tracking 10000 rays with different wavelengths and heights in an Offner example system, the results show that analytical model can quickly reproduce the spot diagrams with a high degree of accuracy. With these formulas coma, spherical aberration, astigmatism and distortion are discussed in detail. The analytical model provides theoretical guidance for the optimal design of Offner imaging spectrometers..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 322001 (2011)
Freeform-Surface Design of Off-Axis Illumination in Projection Lithography
Xing Shasha, Wu Rengmao, Li Haifeng, Zheng Zhenrong, and Liu Xu
Off-axis illumination is an important application of resolution enhancement technology in projection lithography. An approach of designing freeform lens for off-axis illumination (OAI) in optical lithography is propose. Based on the mapping between the source and the target and conservation law of energy, a set of partOff-axis illumination is an important application of resolution enhancement technology in projection lithography. An approach of designing freeform lens for off-axis illumination (OAI) in optical lithography is propose. Based on the mapping between the source and the target and conservation law of energy, a set of partial differential equations are obtained and numerically solved, and then optical performances of the freeform lenses are simulated. With the method, free form surfaces are designed to achieve an annular, dipole, quadrupole lighting. The shape and intensity of illumination distribution on the target surface can be controlled precisely. Also, the illumination efficiency is over 90% and good uniformity can be achieved..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 322002 (2011)
Optical Devices
Michelson Interferometer Based Micro-Mechanical Modulator Working on Fiber Signal
Ding Fangyuan, Jia Feng, and Zhang Tianhao
A micro-mechanical modulator is designed based on the Michelson interferometer. In the experiment, the fiber signal is input from the input-sport and divided into two equal parts: the transmitted beam and the reflected beam, by beam-splitter. The modulating voltage signal is amplified and drives the piezoelectric ceramA micro-mechanical modulator is designed based on the Michelson interferometer. In the experiment, the fiber signal is input from the input-sport and divided into two equal parts: the transmitted beam and the reflected beam, by beam-splitter. The modulating voltage signal is amplified and drives the piezoelectric ceramic pipe to do stretch oscittation in order to modulate the optical-path difference between the transmitted beam and the reflected beam. The transmitted beam and the reflected beam are interfered at the output-port and focused into fiber again. Then a modulated fiber signal is obtained. The modulator is operated for amplitude modulation. In the experiment, the modulation ratio is prior to 90%, signal-to-noise ratio is about 18 dB, and the bandwidth is also about 200 kHz. This device has the merit of high modulation ratio and low price, and can be applied as a modulator or chopper in optical signal transmission system..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 323001 (2011)
Fabrication and Characteristics of Film-Under-Gate Field Emission Displays with SnO2 Emitters
Zhang Yongai, Lin Jinyang, Wu Chaoxing, and Guo Tailiang
The film-under-gate field emission arrays (FEA) are fabricated on the glass substrates by conventional photolithography, anodic oxidation and stripping method. SnO2 emitters are migrated on the cathode of film-under-gate triode by screen printing. The images of film-under-gate FEA with SnO2 emitters are measured by theThe film-under-gate field emission arrays (FEA) are fabricated on the glass substrates by conventional photolithography, anodic oxidation and stripping method. SnO2 emitters are migrated on the cathode of film-under-gate triode by screen printing. The images of film-under-gate FEA with SnO2 emitters are measured by the optical microscopy and scanning electron microscopy (SEM). The electron trajectory in this triode is simulated by ANSYS. It shows that the SnO2 emitters by screen printing are uniformly distributed on the surface of cathode. The electron beam size gradually becomes small with the increase of anode voltage and gradually becomes large with the increase of gate voltage. The cathode plate and anode plate are made of a 5 inch monochromatic film-under-gate field emission displays (FED) panel and its field emission performance are investigated. It indicates that the FED with SnO2 emitters can achieve full-screen light emission when the gate voltage and anode voltage are 140 V and 2000 V, respectively, at the anode-cathode spacing of 1100 μm. In addition, the maximum anode current of fabricated device can come to 232 μA and the highest luminance is approximately 270 cd/m2. Moreover, the emission current fluctuation is less than 5% for 400 min, which shows that the film-under-gate field emission displays with SnO2 emitters by screen printing have a good field emission characteristics and good application prospects..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 323002 (2011)
Research of a Novel Configuration of Optically Controlled Delays Based on Stimulated Brillouin Scattering
Yang Xiufeng, Li Qun, Tong Zhengrong, Yao Bin, Li Yuan, Zhao Junfa, and Liu Yange
A novel configuration of multistage slow-light delay based on stimulated Brillouin scattering is presented. The two fiber segments of slow light delay are cascaded by two circulators in the configuration. The pump which propagates through the first-stage delay medium can launch into the second-stage delay medium througA novel configuration of multistage slow-light delay based on stimulated Brillouin scattering is presented. The two fiber segments of slow light delay are cascaded by two circulators in the configuration. The pump which propagates through the first-stage delay medium can launch into the second-stage delay medium through the circulator as the pump of the second delay line. Compared with the conventional configuration, the new one does not need separate pump for each delay medium, has simple structure, high pump efficiency, and good delay effect. When the delay configuration is made of two single-mode fibers which are 12 km long, under the pump power of 5.0 mW, 40.68 dB of Brillouin gain is achieved for the pulse signal of 50 ns, and the delay is up to 46.163 ns through the first section of single-mode fiber. Finally, 90.552 ns delay is obtained through the two segments of fiber, and the efficiency of the pump power is up to 96%..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 323003 (2011)
Effects of Human-Body-Mode Electrostatic-Discharge on GaN-Based Power Light-Emitting Diode
Cui Desheng, Guo Weiling, Cui Bifeng, Ding Tianping, Yin Fei, and Yan Weiwei
High-power blue light-emitting diodes were biased by negative Human-Body-Mode electrostatic discharge(ESD) with -200, -400, -600, -800, -1100 and -1500 V. The electrical and optical parameters of the LED were measured before and after ESD stressing. The failure mechanisms resulted in by ESD stress were analysised afterHigh-power blue light-emitting diodes were biased by negative Human-Body-Mode electrostatic discharge(ESD) with -200, -400, -600, -800, -1100 and -1500 V. The electrical and optical parameters of the LED were measured before and after ESD stressing. The failure mechanisms resulted in by ESD stress were analysised after each ESD stress. The LED had evident soft breakdown due to the generation of defect in active region and cladding layers after ESD stressing at -200, -400, -600 and -800 V. However, when the device was biased to -1100 V and -1500 V, high leakage current of the LED appears and 50% degradation of light output than before stressing. The reason is the generation of melting thread in active region that made LED cannot emit light. In addition, a simple and effective protection circuit for ESD is proposed..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 323004 (2011)
Design of Multimode Optical Power Splitter Based on Asymmetric Arc-Shaped Y Branch Unit
Li Shu, Lin Qiao, and Wu Xingkun
Efforts are made to obtain a novel multimode optical power splitter based on asymmetric Y splitter by means of beam propagation method (BPM). As lack of uniformity for multimode light power in waveguides, a special asymmetric Y branch on curves is brought into the structure to reach an evenly divided power output. RelaEfforts are made to obtain a novel multimode optical power splitter based on asymmetric Y splitter by means of beam propagation method (BPM). As lack of uniformity for multimode light power in waveguides, a special asymmetric Y branch on curves is brought into the structure to reach an evenly divided power output. Relation between splitter parameters and the output power has been analyzed. A series of equations for the splitter structure design are obtained. Both 1×4 and 1×8 power splitter designs with a 62.5 μm and 120 μm waveguide width respectively are provided with an overall length of 7.6 mm and 21.7 mm, respectively. The calculation results show that these splitters exhibit an excellent splitting uniformity in 1.31 μm window. The calculated insertion loss for the two designs are 6.05 dB and 9.06 dB with the polarization-dependent loss to be 0.2 dB..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 323005 (2011)
Design of New Photonic Crystal All-Optical Switching Based on Dynamical Shift of Defect Mode
Chen Heming, and Wang Guodong
A new type of photonic crystal all-optical switching based on the dynamical shift of defect mode has been designed. This photonic crystal is triangular lattice with circular air holes in silicon, in which line defects and point defects are included. A photonic crystal structure introducing both point and line defects wA new type of photonic crystal all-optical switching based on the dynamical shift of defect mode has been designed. This photonic crystal is triangular lattice with circular air holes in silicon, in which line defects and point defects are included. A photonic crystal structure introducing both point and line defects which has quality defect mode is designed. After that, point defects have been filled with the Kerr nonlinear optical materialpolydiacetylene para-toluene sulfonate (PDA-PTS). With regulating the control light, the defect mode brings the dynamical shift, and accordingly it can be controled the signal light on and off. The two-dimensional finite-difference time-domain (FDTD) calculation has been used to numerical demonstration. The results show that the switch has great extinction ratio, low threshold power density, and fast switching time. The photonic crystal all-optical switching based on the dynamical shift of defect mode has an important academic significance to the high-speed all-optical communications, as well as the optical computing technology in the future..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 323006 (2011)
Physical Optics
Polarization Properties of Spatially and Spectrally Partially Coherent Electromagnetic Hermite-Gaussian Pulsed Beams
Wang Haixia, Ding Chaoliang, Zhang Yongtao, and Pan Liuzhan
Based on the coherence theory of non-stationary fields, the spectral degree of polarization of two-dimensional spatially and spectrally partially coherent electromagnetic Hermite-Gaussian pulsed beams propagating in free space is studied and analyzed numerically. It is shown that the spectral degree of polarization of Based on the coherence theory of non-stationary fields, the spectral degree of polarization of two-dimensional spatially and spectrally partially coherent electromagnetic Hermite-Gaussian pulsed beams propagating in free space is studied and analyzed numerically. It is shown that the spectral degree of polarization of electromagnetic Hermite-Gaussian pulsed beams depends on the beam order, spatial correlation length, temporal coherence length and the position of the field point. The on-axis spectral degree of polarization, which is independent of the beam order and the position of the field point, tends to a fixed value when the spatial correlation length tends to zero or infinite. The on-axis spectral degree of polarization increases with the increase of temporal coherence length, and decreases with the increase of pulse duration when the beam order is large or the propagation distance is long. The larger the beam order is, the more times the spectral degree of polarization P=0 appears on cross section..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 326001 (2011)
Study on Influencing Factors of Transverse Shift in Spin Hall Effect of Light
Yin Hongfang, Luo Hailu, and Wen Shuangchun
The spin Hall effect of light when a beam passed through an interface between air and glass is studied. The qualitative influence of polarization state, refractive-index difference, incident angle upon the transverse shift of beam centroid is revealed. The transverse shift in both the reflected beam and the refracted bThe spin Hall effect of light when a beam passed through an interface between air and glass is studied. The qualitative influence of polarization state, refractive-index difference, incident angle upon the transverse shift of beam centroid is revealed. The transverse shift in both the reflected beam and the refracted beam increased with increase of the polarization parameters. Left- and right-handed circularly polarized light exhibite an equivalent shifts but opposite in signs. The transverse shift of circularly polarized light is more than the elliptically polarizatied light. The transverse shift of the refracted light increases with increase of the refractive index difference, while the transverse shift of the reflected light decreases, but the transverse shift will vanishe when the refractive index difference nears zero. The transverse shift present an extremal point in the reflected beam, while exhibits a progressive increase in the refracted beam with increase of the angle of incidence. These findings will provide us a theoretical basis to modulate and enhance the spin Hall effect of light..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 326002 (2011)
Quantum Optics
Resonance-Enhanced Optical Parametric Down Conversion
Bai Yunfei, Liu Hongyu, Gao Jiangrui, and Zhang Junxiang
Multi-photon entangled states which are produced mainly by the process of spontaneous parametric down conversion between laser and second-order nonlinear material is a key resource in the quantum network. Although the application of pulsed laser improves the nonlinear conversion efficiency and simplifies the quantum coMulti-photon entangled states which are produced mainly by the process of spontaneous parametric down conversion between laser and second-order nonlinear material is a key resource in the quantum network. Although the application of pulsed laser improves the nonlinear conversion efficiency and simplifies the quantum communication protocol, it is still necessary to enhance the interaction between laser and material for improvement of multi-photon production rate. A resonant cavity for femtosecond pulse is designed to increase the parametric gain and multi-photon production rate while keeping its repetition rate and comb structure. The improved single- and two-photon production rate of cavity system are enhanced by 6.25 and 38.6 respectively compared with that of the single-pass system. The experimental results show agreement with theoretical predication..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 327001 (2011)
Scattering
Light Scattering Properties of Fractal Aggregates
Wang Hongxia, Ma Jin, Song Zibiao, and Liu Daizhi
The shape and aggregation of particle have a strong influence on the light scattering property. The diffusion-limited aggregation model (DLA) of fractal growth is used to simulate the possible structures of aggregates, and the fractal dimension of aggregates is calculated with the method of gyration radius. The light sThe shape and aggregation of particle have a strong influence on the light scattering property. The diffusion-limited aggregation model (DLA) of fractal growth is used to simulate the possible structures of aggregates, and the fractal dimension of aggregates is calculated with the method of gyration radius. The light scattering property of nano-graphite aggregates is studied on the basis of discrete dipole approximation (DDA) method. For aggregates with different numbers of primary particles and with different fractal structures, numerical results of the scattering intensity and the degree of linear polarization to different incident wavelengths are illustrated. The results show that the light scattering properties of nano-graphite aggregates are related to incident wavelength, particle numbers and fractal dimension, and are different from those of the equal volume sphere..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 329001 (2011)
Thin Films
Blue Electroluminescence from Ce3+ Ion Implant Doped Diamond Thin Films
Wang Lijun, Wang Zi, Zhu Yuzhuan, Zhang Shi, and Wang Xiaoping
Ce 3+ ion implant doped diamond thin films are made by using chemical vapour deposition system and ion implant system. Their electroluminescence (EL) characteristic has been investigated. The experimental results indicate that the EL spectrum shows the main peak centered at 476 nm, and the other weaker peak at 435 nm (Ce 3+ ion implant doped diamond thin films are made by using chemical vapour deposition system and ion implant system. Their electroluminescence (EL) characteristic has been investigated. The experimental results indicate that the EL spectrum shows the main peak centered at 476 nm, and the other weaker peak at 435 nm (belong to blue light emission) . The intensity of EL increases obviously with Ce3+ ion implant..
Acta Optica Sinica
- Publication Date: Aug. 13, 2021
- Vol. 31, Issue 3, 331001 (2011)
Study on Effect of Thermal Stress on Microbridges of Uncooled IRFPA and Controlling Methods
Wang Zhi, Xu Xiangdong, Zhou Dong, Yang Zhuo, Jiang Yadong, and Chen Chao
In the micro-fabrication process of microbridges of uncooled infrared focal plane arrays (IRFPA), the microbridges are deformed by the thermal stress in thin films due to the acute temperature changes. Such deformation is harmful to the devices. The deformation of the microbridges is analyzed and two ways to control thIn the micro-fabrication process of microbridges of uncooled infrared focal plane arrays (IRFPA), the microbridges are deformed by the thermal stress in thin films due to the acute temperature changes. Such deformation is harmful to the devices. The deformation of the microbridges is analyzed and two ways to control the deformation are presented: 1) choosing a better electrode material which has a lower thermal expansion coefficient and smaller Young modulus; 2) adding another SiNx thin film on the surface of electrode. Results indicate that by using above two ways, the deformation can be efficiently reduced from 1.4740 μm to 0.4799 μm and 0.0704 μm respectively, the aim of controlling the deformation is achieved..
Acta Optica Sinica
- Publication Date: Jun. 18, 2020
- Vol. 31, Issue 3, 331002 (2011)
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