Contents
2012
Volume: 32 Issue 11
50 Article(s)
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Research Article
Comparison and Improvement of the Atmospheric Optical Turbulence Model in Near Sea Surface
Li Yunbo, Huang Xiaomao, Yu Junhao, and Zhao Yaming
Four atmospheric optical turbulenc models are analysed in different stability conditions through atmospheric optical turbulence trial in the Northern Yellow Sea. Focusing on the low precision of model in neutral and near neutral condition, a new form for temperature structure is developed based on the relation between Four atmospheric optical turbulenc models are analysed in different stability conditions through atmospheric optical turbulence trial in the Northern Yellow Sea. Focusing on the low precision of model in neutral and near neutral condition, a new form for temperature structure is developed based on the relation between fT and stability; using trial data and data fitting, the new fT function is proposed. The result of error analysis shows that the C2n model considerably improves the precision using the new fT function..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1101004 (2012)
A Precision Length Measurement Route by Phase-Shifting Inteferometry with Mechanical Scanning
Luo Zhiyong, Gu Yingzi, and Chen Zhaohui
Based on the application background of length measurement, a novel phase-shifting interferometry is presented. A precise phase-shifting device for length measurement by pressure variation is developed. This device based on single-quartz component is made to carry out the generation of triple phase-shifting, and an esseBased on the application background of length measurement, a novel phase-shifting interferometry is presented. A precise phase-shifting device for length measurement by pressure variation is developed. This device based on single-quartz component is made to carry out the generation of triple phase-shifting, and an essential technique to make online calibration of the capacitor sensor is also realized. The original phase is solved by the developed five-interferogram algorithm with the uncertainty of 0.01% phase periods. The experimental results show that the phase-shifting obtained by this device is up to 1 μm and the variation for length measurement is 0.5 nm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1112004 (2012)
Atmospheric Optics and Oceanic Optics
Monte Carlo Radiative Transfer Modeling of Optical Lightning Signals Observed by Satellite
Hu Liqin, and Huang Fuxiang
For the next generation of Chinese geostationary meteorological satellites (FY-4), an optical lightning mapping sensor is planned to observe lightning and storms on a real-time, continual basis. In order to fully benefit from FY-4 lightning observations，it is desirable to establish optical-band radiative transfer simulFor the next generation of Chinese geostationary meteorological satellites (FY-4), an optical lightning mapping sensor is planned to observe lightning and storms on a real-time, continual basis. In order to fully benefit from FY-4 lightning observations，it is desirable to establish optical-band radiative transfer simulation algorithm of lightning, and investigate the properties of lightning radiative transfer and the cloud top radiation signals observed by satellite. Combined observational parameters of FY-4 lightning imager，based on the simplified lightning source and thunderstorm models, a Monte Carlo approach is applied for simulating the transfer of lightning produced photons in thunderclouds, and the outputs are designed to address the lightning radiation signatures obtained by FY-4 lightning mapping sensor. The simulated results show that lightning radiative transfer simulation based on Monte Carlo method can theoretically reveal links between satellite optical-band lightning radiation observation and the most important parameters, and provide extremely valuable information for the future application of lightning data observed by satellite..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1101001 (2012)
Influence of Vertical Distribution of Water Consistent to Precision of Remote Sensing Retrieval Algorithm
Huang Changchun, Li Yunmei, Xu Liangjiang, Yang Hao, Ju Yan, Lü Heng, Chen Xia, and Wang Yanhua
Based on the radiation transfer model, the remote sensing reflectance dataset is simulated under different vertical distributions of chlorophyll-a and suspended particle. In order to study the influence of vertical distribution to the remote sensing retrieval algorithm precision, the dataset is supplied to check the reBased on the radiation transfer model, the remote sensing reflectance dataset is simulated under different vertical distributions of chlorophyll-a and suspended particle. In order to study the influence of vertical distribution to the remote sensing retrieval algorithm precision, the dataset is supplied to check the retrieval model of chlorophyll-a, suspended particle and inherent optical properties. The results indicate that the overestimate of suspended particle band ratio model is greater than single band model under the effect of suspended particle and chlorophyll-a vertical distribution. Chlorophyll-a band ratio and three-band model can reduce the overestimation of chlorophyll-a induced by the suspended particle and chlorophyll-a vertical distribution. The suspended particle and chlorophyll-a vertical distribution have double effects on the inherent optical properties retrieval model. Namely, the suspended particle vertical distribution will lead to overesitmate the absorption and backscattering coefficient, while the chlorophyll-a vertical distribution will lead to underestimate. The results of inherent optical properties retrieval model is uncertain under the double effects of suspended particle and chlorophyll-a..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1101002 (2012)
Atmospheric Pressure Broadening Correction Algorithm of Differential Absorption Atmospheric CO2 Lidar
Ma Xin, Lin Hong, Ma Yingying, and Gong Wei
CO2, as the main component of greenhouse gases, has a major impact on the global climate. Currently, passive observation equipment can only get the CO2 concentration over a single point. However, differential absorption lidar has great advantages in the detection of CO2 and can get higher spatial and temporal resolutioCO2, as the main component of greenhouse gases, has a major impact on the global climate. Currently, passive observation equipment can only get the CO2 concentration over a single point. However, differential absorption lidar has great advantages in the detection of CO2 and can get higher spatial and temporal resolution. At present, when using the differential absorption lidar to detect the concentration of CO2, the pressure broadening cannot be ignored. Focusing on the analysis of pressure broadening, a new correction algorithm is proposed which reduces the error in the inversion process when compared with the classical algorithm. After the inversion of the analog signal and measured signal, ultimately, the ideal results of the vertical profile of CO2 concentration distribution are got and the feasibility of the new correction algorithm is verified..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1101003 (2012)
Detectors
Experimental Investigation on the Effects of the Detector Size and Defocusing Length on Lensless Ghost Diffraction
Luo Chunling, Lin Jie, and Cheng Jing
Lensless ghost diffraction is a kind of correlated imaging technique that produces the diffraction pattern of the object on the reference path by measuring the correlation of intensity fluctuation between the test and reference paths, in which the test path contains the object. The effects of the detector size and defoLensless ghost diffraction is a kind of correlated imaging technique that produces the diffraction pattern of the object on the reference path by measuring the correlation of intensity fluctuation between the test and reference paths, in which the test path contains the object. The effects of the detector size and defocusing length on lensless ghost diffraction imaging with pseudo-thermal light are investigated experimentally. Using a four-slit object in our experiments, how the detector size and defocusing length change the patterns of lensless ghost diffraction is quantitatively studied. The experimental results are well interpreted with the numerical simulations. The image correlation is used to quantitatively analyze the differences between the experimental patterns and the idealized ghost diffraction images. It is found the diffraction quality is decreased with the appearance of the finite size of the detector and the defocusing length..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1104001 (2012)
Diffraction and Gratings
Two-Dimensional Fast Fourier Transform Method of Analyzing the Influence of Plane Grating′s Line Error and Surface Error on Grating′s Spectral Performance
Li Xiaotian, Bayanheshig, Qi Xiangdong, Yu Haili, and Tang Yuguo
Plane grating′s line error and surface error of substrate influence grating′s spectral performance, such as diffraction wavefronts, resolving power, ghost lines, satellites, scattered light etc. It is extremely important to study the relationship among grating performance, line error and substrate′s surface error. AccoPlane grating′s line error and surface error of substrate influence grating′s spectral performance, such as diffraction wavefronts, resolving power, ghost lines, satellites, scattered light etc. It is extremely important to study the relationship among grating performance, line error and substrate′s surface error. According to optical path difference caused by grating′s line error and surface error, math equations, which contain the relationship among line error, surface error, angle of incidence θ, diffraction order m and diffraction wavefront under condition of cone diffraction, are deduced and mathematical model of reconstructing the diffraction wavefronts of non-ideal grating is acquired. Based on above model, grating′s diffraction wavefronts of symmetric orders are measured by interferometer and the separation of grating line error and surface error of substrate are realized from measured results. Grating′s diffraction wavefronts are analyzed by two-dimensional fast Fourier transform method and the influence of grating line error and surface error on grating performance is discussed. With the aid of aforesaid method, grating′s resolving power, ghost lines, satellites, scattered light can be analyzed by reconstructing grating′s diffraction wavefront, and grating′s line error and surface error on the whole surface of grating can be deduced, both of which can provide a theoretical basis for grating′s substrate processing, grating manufacture and application..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1105001 (2012)
Fiber Optics and Optical Communications
Blind Optical Baseband Signals Detection Using Recurrent Neural Network Based on Continuous Multi-Valued Neurons
Ruan Xiukai, and Zhang Yaoju
Spatial diversity reception can be used over wireless optical links to resist channel fading. A novel blind optical baseband signals detection direct algorithm is proposed by using recurrent neural network based on continuous multi-valued neurons (RNNCMVN) with amplitude and phase continuous activation (APCA). ConsiderSpatial diversity reception can be used over wireless optical links to resist channel fading. A novel blind optical baseband signals detection direct algorithm is proposed by using recurrent neural network based on continuous multi-valued neurons (RNNCMVN) with amplitude and phase continuous activation (APCA). Considering the characteristics of mary phase shift keying (MPSK) signals, two types of continuous multi-valued activation functions are designed and the method of selecting their parameters is illustrated briefly. The new energy functions of synchronous and asynchronous mode of the RNNCMVN are derived and proved, respectively. Considering the characteristics of quadrature amplitude modulation (QAM) signals, the new continuous amplitude and phase multi-valued activation functions are designed and discussed, respectively. Finally, simulation results demonstrate the effectiveness of the proposed method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1106001 (2012)
A Cross Traffic Estimate Model for Optical Burst Switching Networks
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
The cross traffic intensity of the optical burst switching networks is a key parameter in the network. This parameter restricts the operation of the assembly algorithm in edge nodes. It is revealed that the service time of the control plane in core nodes, closely related with the cross traffic, is a random variable insThe cross traffic intensity of the optical burst switching networks is a key parameter in the network. This parameter restricts the operation of the assembly algorithm in edge nodes. It is revealed that the service time of the control plane in core nodes, closely related with the cross traffic, is a random variable instead of a deterministic variable in the wavelength conversion devices. Two distinct queuing models named M/D/1 and M/G/1 are constructed to describe the behavior of the core node. An estimate model to infer the cross traffic in the control plane of core nodes is proposed based on the observing variable of residual time of the burst. Numerical simulation results verify that the model can reflect the intensity of cross traffic on the control plane of core nodes in time..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1106002 (2012)
Design of Novel Highly Efficient Photonic Crystal Multi-Channel Drop Filter
Yu Jianli, Shen Hongjun, Ye Song, and Hong Qiusan
Based on the resonant coupling principle between the defect mode of micro-cavity and the waveguide mode, a new multi-channel drop filter is designed using the two-dimensional square lattice photonic crystal. The filter is composed of the bus waveguide, the 90° bend waveguide and the resonant micro-cavitiy. Every cBased on the resonant coupling principle between the defect mode of micro-cavity and the waveguide mode, a new multi-channel drop filter is designed using the two-dimensional square lattice photonic crystal. The filter is composed of the bus waveguide, the 90° bend waveguide and the resonant micro-cavitiy. Every channel drop efficiency of the filter is enhanced greatly due to the perfect combination. The transmission characteristic of the filter is simulated with two-dimensional finite difference time domain method and theoretical analysis is performed in order to understand the important factors affecting the drop efficiency. The optimized device enhances the drop efficiency of every channel drop waveguide to over 91%. The simulation results show that the filter has the ability to download the light wave efficiently. The device has a good wavelength selection performance with the channel spacing of 20 nm, the center accordance less than ±2 nm and the maximal spectral half-width of 3.2 nm. It is demonstrated that the drop efficiency of the filter is improved greatly by increasing the coupling region between the download waveguide and the resonant micro-cavity..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1106003 (2012)
Optical Fiber Communication Performance Monitoring Based on Asynchronous Delay Tap Sampling
Lai Junsen, Yang Aiying, and Sun Yu′nan
Based on asynchronous delay tap sampling and artificial neural network statistical machine learning, a novel optical performance monitoring (OPM) technique is proposed. The signal is delay tap sampled to obtain two-dimensional histogram. Then the features of histograms are extracted to train the artificial neural netwoBased on asynchronous delay tap sampling and artificial neural network statistical machine learning, a novel optical performance monitoring (OPM) technique is proposed. The signal is delay tap sampled to obtain two-dimensional histogram. Then the features of histograms are extracted to train the artificial neural networks. The outputs of trained neural network are used to monitor optical signal impairments. Simulations of optical signal-to-noise ratio, chromatic dispersion and polarization mode dispersion monitoring in 10 Gb/s nonreturn to zero code-on-off keying, 40 Gb/s optical doubinary code and return to zero-differential phase shift keying systems are presented. The simulation results show that the proposed scheme can monitor multiple simultaneous impairments on optical signals of diverse bit rates and formats with high accuracy, from which the monitoring error is less than 5%. The proposed technique is simple, cost-effective and suitable for in-service distributed OPM..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1106004 (2012)
Study of a Novel Symmetrical Interleaver Based on Ring Resonator Assisted Mach-Zehnder Interferometer
Lu Huaiwei, Wu Kaijun, Wei Yun, Wang Chunli, Jiang Zhanjun, and Luo Guanwei
In order to improve the transmission performance of the conventional Mach-Zehnder interferometer (MZI), a novel interleaver combining ring resonator with a single fiber coupler of 3 dB direction is proposed. The ring resonator shaped like an “8” form is based on double-coupler and single-mode fiber. Based on the phase In order to improve the transmission performance of the conventional Mach-Zehnder interferometer (MZI), a novel interleaver combining ring resonator with a single fiber coupler of 3 dB direction is proposed. The ring resonator shaped like an “8” form is based on double-coupler and single-mode fiber. Based on the phase modification provided by the ring resonator, a flatness filtering response is obtained by optimizing the coupling angle of resonator. Compared with the traditional MZI-interleaver and two-stage MZI-interleaver, the isolation in stopband and the rolloff in transition band are strengthened. Compared with the interleaver based on an asymmetrical MZI with a resonator in one arm, there is no difference between the intensities of two coherent light beams in the condition of considering the influence of the propagation loss. Theoretical analysis shows that the influence of the propagation loss on extinction ratio can be effectively reduced by proposed interleaver..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1106005 (2012)
Analysis of Phase Noise Induced by Four-Wave Mixing in Long-Haul Optical Orthogonal Frequency-Division Multiplexing Based on Wavelet Transforms
Gao Haiyue, and Pan Wei
Four-wave mixing (FWM) is the most important nonlinear effect in coherent optical orthogonal frequency-division multiplexing (CO-OFDM) system. The principle of CO-OFDM system based on wavelet transforms (WT-OOFDM) is analyzed, and effect of wavelet transforms on phase noise caused by FWM and amplified spontaneous emissFour-wave mixing (FWM) is the most important nonlinear effect in coherent optical orthogonal frequency-division multiplexing (CO-OFDM) system. The principle of CO-OFDM system based on wavelet transforms (WT-OOFDM) is analyzed, and effect of wavelet transforms on phase noise caused by FWM and amplified spontaneous emission (ASE) of optical amplifiers is discussed. For the conventional optical fiber G. 652, 100 Gbit/s WT-OOFDM system, the simulation results show that the variance of the total phase noise can be decreased by 15%, and the nonlinear phase noise has a 20% reduction while the transmission distance reaches 1500 km..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1106006 (2012)
Geometric Optics
A Method of Analyzing Image Distortion Based on Conjugate Nodal Plane
Zhang Chunming, Xie Yongchun, Wang Li, Zhao Chunhui, and Zhong Hongjun
The imaging model of an optical camera without aberration can be equivalently expressed by its conjugate nodal plane model. A pinhole camera model neglects aberration of corresponding equivalent model, and also fails to represent translation error of flat glass, tilt error of optical axis as well as aberration of an acThe imaging model of an optical camera without aberration can be equivalently expressed by its conjugate nodal plane model. A pinhole camera model neglects aberration of corresponding equivalent model, and also fails to represent translation error of flat glass, tilt error of optical axis as well as aberration of an actual optical system. All of these four factors give rise to image distortion. Based on this, a geometry model of image distortion is proposed by utilizing the property of conjugate nodal plane. By comparing with commonly used aberration model, this model can theoretically interpret their physical significances. The simulation of an actual optical system indicates that the relative radial distortion and relevant angle error both calculated by this model appears in the range of rational design parameters. Meanwhile, the phenomenon of asymmetric image distortion is seen. In this model, four unknown parameters needed to be recognized are relevant parameters of principal plane, tilt angle of optical axis and axial spherical aberration of flat glass. Theoretically, this geometric model can be used to correct image distortion with less parameters to be identified..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1108001 (2012)
Imaging Systems
A Method for Distortion Correction of Airborne Mapping Camera with Forward Image Displacement Compensation
Yuan Guoqin, Ding Yalin, Hui Shouwen, Zhang Jingguo, Zheng Lina, Yu Chunfeng, Liu Liguo, Chen Wei, and Zhang Xuefei
In order to improve the mapping accuracy, a new algorithm is proposed to calibrate optical system distortion when forward image displacement is compensated by driving CCD. The key factors which greatly influence the optics distortion during forward image displacement compensation are researched. Then, by analyzing the In order to improve the mapping accuracy, a new algorithm is proposed to calibrate optical system distortion when forward image displacement is compensated by driving CCD. The key factors which greatly influence the optics distortion during forward image displacement compensation are researched. Then, by analyzing the effect of principal point and the principal distance on the optical distortion, a mathematical model is established. The model is tested through numerical simulation and field flight experiment. Experimental results show that the mapping accuracy is improved by 1.38 times as compared with the traditional method. The results confirm the feasibility and the validity of the proposed method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1111001 (2012)
Instrumentation, Measurement and Metrology
Analysis of Vibration Effect to Surface Figure Measurement
Wang Rudong, Tian Wei, Wang Ping, and Wang Lipeng
Vibration introduces error to high accuracy surface figure measurement. The vibration error model of the surface figure measurement is established by interferometry. When the vibration amplitude is 63 nm, the sensitive vibration frequency of the surface figure measurement is 12 Hz, and the surface figure root mean squaVibration introduces error to high accuracy surface figure measurement. The vibration error model of the surface figure measurement is established by interferometry. When the vibration amplitude is 63 nm, the sensitive vibration frequency of the surface figure measurement is 12 Hz, and the surface figure root mean square (RMS) error is about 12 nm caused by vibration through using the thirteen-step algorithm. The simulation result and the experimental result are almost the same. According to the experimental analyses, the RMS error of surface figure varies from 1 nm to 7.1 nm, when the vibration frequency is 12 Hz and the amplitude varies from 5 nm to 63 nm, and the surface figure RMS error increases linearly with the vibration amplitude. It can provide a certain reference for the environment control of vibration when measuring high accuracy surface figure through analyzing the surface figure error at different vibration frequencies and amplitudes..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1112001 (2012)
Image Motion Velocity Measurement Technique Based on Spatial Filtering Effect of Line CCD for Aerial Camera
Zheng Lina, Zhang Tao, Kuang Haipeng, Li Wenming, Yang Yongming, and Yuan Guoqin
Based on spatial filtering velocimetry, a new method is proposed by using spatial filtering effect of line CCD for aerial camera. Spatial filtering characteristic of spatial slits is simulated by doing interval sampling with line CCD image, by which an optical non-contact measurement about aerial camera image motion veBased on spatial filtering velocimetry, a new method is proposed by using spatial filtering effect of line CCD for aerial camera. Spatial filtering characteristic of spatial slits is simulated by doing interval sampling with line CCD image, by which an optical non-contact measurement about aerial camera image motion velocity is realized. Besides, with the research of spatial filtering power spectrum density function, key factors affecting the spatial filtering characteristic of line CCD are analyzed. The possibility of measurement about image motion velocity with line CCD push broom image simulating spatial filtering effect is validated with experiments. The results show that the measurement error is less than 1/3 pixel for an image motion velocity between 5 and 53.2 mm/s, which satisfies the requirement of image motion compensating precision for aerial camera..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1112002 (2012)
Camera Internal-Parameters Calibration Based on the Construction of Initial Measurement Network
Yu Zhijing, and Pan Xiao
The camera internal parameters calibration method based on building the initial measurement of the network is put forward. The lack of direction depth of the plane target, as well as the constraints in three-dimensional target space, is solved effectively. In accordance with the principle of measurement network, after The camera internal parameters calibration method based on building the initial measurement of the network is put forward. The lack of direction depth of the plane target, as well as the constraints in three-dimensional target space, is solved effectively. In accordance with the principle of measurement network, after the imaging of the target board, the initial measurement network is established. After resection for solving the exterior orientation, forward intersection for the spatial coordinates of encoded points attached on the target board, the camera parameters are solved by the iterative optimization finally. And then, the internal parameters are used for solving the space coordinates. The experimental results show that an average error of building the initial network value of 0.0794 is superior to values of -0.2443 and -0.1916 of planar-taget and three-dimensional-taget calibration. Besides, the calibration time is significantly less than the virtual three-dimensional calibration. This method has the advantages of fast, accurate and efficient, can meet the requirements of the current large-scale vision measurement in the internal parameters calibration on site..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1112003 (2012)
Multi-Pulse Train Cross-Correlation Method in Remote Laser Ranging
Ni Xuxiang, and Hu Kai
With the limitation of single-pulsed laser ranging technology in long distance laser ranging, a new ranging technology based on the cross-correlation between the transmitted pulse train is proposed. A laser system which can modulate pulse’s intensity and intervals is applied to simulate different echo pulses. A series With the limitation of single-pulsed laser ranging technology in long distance laser ranging, a new ranging technology based on the cross-correlation between the transmitted pulse train is proposed. A laser system which can modulate pulse’s intensity and intervals is applied to simulate different echo pulses. A series of experiments are designed to explore the abilities of the technology in improving signal to noise ratio (SNR), suppressing noise and measuring time, and good results are got. The SNR is improved from 0.11 to 5.92, which extends laser ranging, decreases alarm rate of the detection system and increases ability of exploring weak echo pulse..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1112005 (2012)
Adaptive Phase Extraction Method Based on Hilbert-Huang Transform
Wang Chenxing, and Da Feipeng
Based on Hilbert-Huang transform, an adaptive phase extraction method is proposed. Signals of fringe pattern are decomposed into a series of intrinsic mode functions (IMF) by empirical mode decomposition. Criteria are presented to determine noise IMF and to identify whether mode-mixing problem exists in the correspondiBased on Hilbert-Huang transform, an adaptive phase extraction method is proposed. Signals of fringe pattern are decomposed into a series of intrinsic mode functions (IMF) by empirical mode decomposition. Criteria are presented to determine noise IMF and to identify whether mode-mixing problem exists in the corresponding noise IMF through the analysis of Hilbert spectra for each IMF. If the problem exists, new “noise” is designed adaptively according to the noise IMF and added into the original signals. The new formed signals are decomposed again. Repeat the process iteratively until the mode-mixing problem disappears. Noise IMF and background components determined in the last decomposition are subtracted from the last formed signals to get the fundamental signals, on which is performed Hilbert transform to obtain the wrapped phase. The presented method can overcome the mode-mixing problem effectively and keep detailed phase information while removing the noise and background components. The adaptability and robustness of the method is good..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1112006 (2012)
Two-Step Wavelength Tuning Absolute Testing Method of the Optical Homogeneity of Optical Material
Li Jianxin, Guo Renhui, Zhu Rihong, Chen Lei, and He Yong
Optical homogeneity is one of the most important parameters of optical material. The traditional absolute testing method is considered to be the high-precision way of optical homogeneity measurement. However its corresponding operation procedure is very complex. So it is sensitive to the environmental fluctuation. BaseOptical homogeneity is one of the most important parameters of optical material. The traditional absolute testing method is considered to be the high-precision way of optical homogeneity measurement. However its corresponding operation procedure is very complex. So it is sensitive to the environmental fluctuation. Based on the characteristics of wavelength tuning, two-step wavelength tuning absolute testing method of the optical homogeneity is presented. It only consists of two measurement steps, with and without the parallel plate as the material in the test arm cavity between transmission flat and reflective flat. The presented method is verified in terms of numerical simulation. And the measurement experiments with both the traditional absolute testing method and the presented method are carried out. In the end, the experimental result shows the validity of the presented testing method. After comparison, it is clear to see that the presented method is of high precision, which is simpler than the traditional one..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1112007 (2012)
Influence of Nonpolarizing Beam Splitters on Nonlinear Error in Heterodyne Interferometers
Deng Yuanlong, Li Xuejin, Geng Youfu, and Hong Xueming
In a laser heterodyne interferometer, nonpolarizing beam splitters (NPBS) are also the important nonlinear error sources besides laser sources, polarizing beam splitters (PBS), wave plates and other polarizing components. The influence of depolarization effect and misorientation of a multi-layer dielectric NPBS on the In a laser heterodyne interferometer, nonpolarizing beam splitters (NPBS) are also the important nonlinear error sources besides laser sources, polarizing beam splitters (PBS), wave plates and other polarizing components. The influence of depolarization effect and misorientation of a multi-layer dielectric NPBS on the nonlinear error is investigated. The depolarization effect is characterized as the reflectance, transmittance, reflection-induced-retardance (RIR) and transmission-induced-retardance (TIR) between the p- and s- components. The producing mechanism of the nonlinear error is accordingly analyzed. Only the RIR and TIR have contribution to the nonlinear error while the incident light is in ideal polarization state. Otherwise the variation of the misorientation and the depolarization effect will introduce nonlinear error, and the error slopes are affected by the elliptical polarization and non-orthogonality. Therefore the error introduced by the same NPBS varies with laser sources used in interferometers. Generally it will be up to several nanometers. A NPBS with steady performance should be selected to seek nanometer even sub-nanometer accuracy. The parameters match between the depolarization effect of NPBS and the polarization state of laser source should also be attached more importantly..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1112008 (2012)
Measurements of Terahertz Wavelength Using Metallic Mesh Fabry-Pérot Interferometer
Jiang Chengyue, Cai Rui, Liu Jinsong, Wang Kejia, and Wang Shenglie
Several metallic mesh Fabry-Pérot interferometers (FPI) are designed and manufactured to measure terahertz waves with wavelengths larger than 150 μm (that is less than 2 THz in frequency). Metallic meshes with five different structural parameters whose periods are less than 40 μm and linewidths are less than 10 μmSeveral metallic mesh Fabry-Pérot interferometers (FPI) are designed and manufactured to measure terahertz waves with wavelengths larger than 150 μm (that is less than 2 THz in frequency). Metallic meshes with five different structural parameters whose periods are less than 40 μm and linewidths are less than 10 μm are fabricated by employing optoelectronics micro-nano manufacturing technology. By using terahertz time-domain spectroscopy, the refractive indices of the meshes and the refractive finesses of the FPI in terahertz wave band are obtained. Results show that all the meshes can work well for the interesting wavelengths. In order to test the feasibilities of the FPI, a wavelength of 212 μm is measured. Results show good agreements with theory. Moreover, dependences on the polarization orientation of the terahertz waves and the parallelism of the FPI are also demonstrated, and it is found that the FPI is insensitive to the polarization of the terahertz waves while susceptible to the parallelism of the FPI..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1112009 (2012)
Lasers and Laser Optics
Theory and Experiment of Generating Multi-Bottle Beam with Higher Light-Intensity Gradient
Cheng Zhiming, Wu Fengtie, Fang Xiang, and Fan Dandan
Multi-bottle beam with higher light intensity gradient is generated by superposition of Bessel beam and spherical wave in experiment. The field is analyzed with diffraction theory, and according to the result of simulation by software, multi-bottle beam nearby the focus of spherical wave is obtained. In experiment, BesMulti-bottle beam with higher light intensity gradient is generated by superposition of Bessel beam and spherical wave in experiment. The field is analyzed with diffraction theory, and according to the result of simulation by software, multi-bottle beam nearby the focus of spherical wave is obtained. In experiment, Bessel beam and spherical wave are generated by axicon and convex lens, respectively, multi-bottle beam is obtained nearby focus as two light waves superposed on the same axis. Comparison of the intensity distribution of bottle beam (BB) generated by the two methods shows that BB generated by interference of Bessel beam and spherical wave has higher intensity gradient in the dark area, which is superior in particles imprison..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1114001 (2012)
Second Harmonic Generation of Gaussian Beam in Single and Twin Crystal of Barium Metaborate Medium
Pang Wanwen, Wang Yan, Liu Zhikun, Liu Qi, Bai Lihua, and Zhang Huifang
The coupled wave equations for frequency doubling of Gaussian beam propagating in birefringent uniaxial anisotropic medium are given. Based on them, specific physical models of single and twin crystal of barium metaborate (BBO) material have been established, and numerically computed results show the distribution of haThe coupled wave equations for frequency doubling of Gaussian beam propagating in birefringent uniaxial anisotropic medium are given. Based on them, specific physical models of single and twin crystal of barium metaborate (BBO) material have been established, and numerically computed results show the distribution of harmonic power flow, the electric field temporal distribution of harmonic at probe point on exit surface of the crystal, the output total energy, the output spectra of light and also the input angular spectra of beam. We make detailed analysis of various influences mainly from beam waist, medium structure and properties of material on second harmonic generation and give some reasonable explanations. The research results will benifit the study on nonlinear optical properties of uniaxial medium and optical crystal devices..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1114002 (2012)
Wavelength-Swept Fiber Laser Based on Dispersion Tuning and Its Application on the Demodulation of Fiber Bragg Grating
Mei Jiawei, Xiao Xiaosheng, Xu Mingrui, Gui Lili, and Yang Changxi
A large swept-range wavelength-swept Er-doped fiber laser based on dispersion tuning is reported. By introducing large dispersion in the cavity of the active mode-locked laser, the output wavelength can be swept through changing modulation frequency. The laser can be applied to fiber Bragg grating (FBG) sensing. When tA large swept-range wavelength-swept Er-doped fiber laser based on dispersion tuning is reported. By introducing large dispersion in the cavity of the active mode-locked laser, the output wavelength can be swept through changing modulation frequency. The laser can be applied to fiber Bragg grating (FBG) sensing. When the output light of the wavelength-swept laser is reflected by FBG, the variation of FBG central wavelength induced by strain can be converted into different time delays of signals. The output characteristics of the wavelength-swept laser are experimentally studied. The wavelength-swept range is 43 nm approximating the gain bandwidth of Er-doped fiber, while the sweep rate is 50 Hz. The principle of this demodulation technique is demonstrated and the sensitivity is about 0.68 ms/nm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1114003 (2012)
Active High-Accuracy Shock-Wave Velocity Measure Technique in Laser Indirect-Drive Experiment
Wang Feng, Peng Xiaoshi, Liu Shenye, Jiang Xiaohua, Xu Tao, and Ding Yongkun
Laser indirect-drive has potential to get ultra-high pressure which is very useful for shock-wave physics. A step target is used to get the equation of state (EOS) data under high pressure with laser drive experiment. Since there are preheat effects in step targets, an active velocity interferometer system for any reflLaser indirect-drive has potential to get ultra-high pressure which is very useful for shock-wave physics. A step target is used to get the equation of state (EOS) data under high pressure with laser drive experiment. Since there are preheat effects in step targets, an active velocity interferometer system for any reflector (VISAR) is presented to adjust the thickness change. The thickness change can be obtained after the calculation of fringe changes. The step thickness can be achieved accurately after corrected preheat effect on the thickness. Under conditions for the steady velocity in step target, shock-wave velocity can be gained from experimental data. This technique is suitable for the shock-wave experiment with radiation drive, which provides data of the shock-wave velocity for equation of state with high accuracy..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1114004 (2012)
Machine Vision
Testing of Low-Contrast Target Acquisition for Photoelectric Tracker
Ye Lu
A detection method for measuring the ability of opto-electronic tracker which captures low-contrast target is proposed. With infinite target source of adjustable contrast as detection device, optical reference target whose contrast can be accurately measured is provided for detected opto-electronic tracker, which is paA detection method for measuring the ability of opto-electronic tracker which captures low-contrast target is proposed. With infinite target source of adjustable contrast as detection device, optical reference target whose contrast can be accurately measured is provided for detected opto-electronic tracker, which is particularly used for testing acquisition ability of opto-electronic tracker for low contrast target. Principle and composition of the detection device, calibration method for target′s contrast are introduced, and detection results are analyzed. Through the research of the detection method, it is realized to evaluate the ability that the whole opto-electronic tracker captures low contrast target. The detection method involves performance of optical system, performance of photoelectric receiver, image processing circuit, software, signal-to-noise ratio and related indexes which influence target contrast, which reflect tracking performance of television tracker all-sidedly and truthfully..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1115001 (2012)
Materials
Magnetic-Medium Assistant Polishing of Silicon Modification Layer on Silicon Carbide Surface
Zhang Feng, and Deng Weijie
To actualize precise polishing of silicon modification layer on silicon carbide surface, and achieve high-quality optical surface, a technology of magnetic-medium assistant polishing is studied. The special magnetic polishing tool for polishing silicon modification layer on silicon carbide surface is designed, and the To actualize precise polishing of silicon modification layer on silicon carbide surface, and achieve high-quality optical surface, a technology of magnetic-medium assistant polishing is studied. The special magnetic polishing tool for polishing silicon modification layer on silicon carbide surface is designed, and the material removal function of magnetic polishing tool is studied. On the basis of the material removal function, the dwell time algorithm of computer-controlled magnetic-medium assistant polishing is researched. A Si-modified on silicon carbide surface experimental sample is polished by magnetic-medium assistant polishing technology. Initial figure error and roughness of the sample are 0.049λ（λ=0.6328 μm) (root-mean-square) and 2 nm. After one polishing iteration, the figure error and roughness of the sample are 0.015λ（λ=0.6328 μm) and 0.64 nm, respectively. Experimental results indicate the dwell time algorithm based on matrix algebra is effective, and magnetic-medium assistant polishing is appropriate for polishing silicon modification layer on silicon carbide surface..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1116001 (2012)
Single Crystal Photo-Elastic Modulator Based on Lithium Niobate Piezoelectric and Photo-Elastic Effect
Chen Youhua, Zhang Jilong, Wang Yanchao, Wei Haichao, Wang Zhibin, Zhang Rui, and Wang Lifu
In order to overcome the disadvantage of Kemp-type photo-elastic modulator such as low modulation efficiency, processing technology difficulty, bulky et al., a photo-elastic modulation mode is proposed. Which uses LiNbO3 crystal piezoelectric properties to produce single crystal photo-elastic modulator. According to thIn order to overcome the disadvantage of Kemp-type photo-elastic modulator such as low modulation efficiency, processing technology difficulty, bulky et al., a photo-elastic modulation mode is proposed. Which uses LiNbO3 crystal piezoelectric properties to produce single crystal photo-elastic modulator. According to the theory of piezoelectric vibration and crystal optics principle, the crystal orientation dependence of physical properties is analyzed, and the relations of displacement and retardation amplitudes over voltage are derived. Then, the cutting-type and the optical path are optimized. The device is designed with dimensions 41 mm×7.7 mm× 17.1 mm in x-, y- and z-direction, 0° cutting angle (x-cut), z-axis for the optical path and electrodes on the xz-surfaces offer basic modulation frequencies at 73.71 kHz corresponding to the longitudinal oscillations in x-direction. Finally, the corresponding experimental equipment is built for the experimental verification; the result shows that: the voltage amplitude to achieve a half-wave retardation amplitude is only about 1.6 V for 633 nm wavelength, and the modulation voltage reduces about 4 times, compared with the LiTaO3 signal-crystal photo-elastic modulator whose cutting-type isn′t optimized..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1116002 (2012)
Optical Design and Fabrication
Design of Conformal Dome Inner Surface Shape Beneficial to Aberration Correction
Zhang Wang, Zuo Baojun, Chen Shouqian, Hu Haili, and Fan Zhigang
In a conformal optical system, the incident parallel light rays are no longer parallel when transmitting through an ellipsoidal dome, and transform into diverging light rays which greatly increase the system′s aberration. This is bad for the subsequent aberration correction. This paper breaks the condition of equal thiIn a conformal optical system, the incident parallel light rays are no longer parallel when transmitting through an ellipsoidal dome, and transform into diverging light rays which greatly increase the system′s aberration. This is bad for the subsequent aberration correction. This paper breaks the condition of equal thickness and redesigns the inner surface of the conformal dome. Consequently, the aberrations of system are corrected by using less optical lenses when compared with equal thickness dome. By analyzing aberration correction results of different order aspheric surfaces as the inner surface of dome, six-order aspheric surface is selected as the initial structure. By optimizing the inner surface of dome, the final shape of inner surface is achieved. The results show that this method obviously reduces the aberrations induced by the conformal domes. Finally, aberrations of the conformal dome are corrected by using the fixed correctors. The results show that the number of the optical elements decreases by redesigning the inner surface of the dome, and this method has a good effect on correcting aberrations..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1122001 (2012)
Design of a Novel Wide View-Field Angle and Anti-Stray-Light Fundus Camera
Yang Jiaqiang, Cheng Dewen, Wang Qingfeng, and Wang Yongtian
A novel portable free-dilated fundus cameras with large field of view (FOV) is designed. By taking consideration of human eye′s aberration and vergence, as well as the sharing of the eye-piece objective lens between the illumination system and the imaging system, a lens system with 16 configurations is set up for optimA novel portable free-dilated fundus cameras with large field of view (FOV) is designed. By taking consideration of human eye′s aberration and vergence, as well as the sharing of the eye-piece objective lens between the illumination system and the imaging system, a lens system with 16 configurations is set up for optimization. As a result, an FOV of 60° and 2 mega pixels resolution have been achieved. The camera can be adapted to eyes in which vergence ranges from -8 D to +10 D; the modulation transfer function (MTF) values of all fields are higher than 0.2 at 120 lp/mm with distortion less than 5%. In order to eliminate the stray light reflected by cornea, ring-shaped LED light source is used to replace traditional Kohler illumination system. The method not only ensures illumination uniformity on fundus, but also greatly improves illumination efficiency and dramatically simplifies the system. A polarizing beam splitter (PBS) and a quarter-wave retarder are used to replace the traditional beam splitter and the black dot board for the first time to shield the stray light. 99.5% of the stray light caused by the eye-piece objective lenses is eliminated..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1122002 (2012)
Optimization Design for Progressive Addition Lenses by Pointwise Directional Curvature Compensation
Qin Linling, Qian Lin, and Yu Jingchi
A global optimizing method using pointwise directional curvature compensation which can reduce the undesirable astigmatism is proposed. The calculation formula of normal curvature at arbitrary direction is deducted and the method is proposed to determine the principal curvature and principal direction. The principal cuA global optimizing method using pointwise directional curvature compensation which can reduce the undesirable astigmatism is proposed. The calculation formula of normal curvature at arbitrary direction is deducted and the method is proposed to determine the principal curvature and principal direction. The principal curvature difference and the directions of the maximum and minimum curvature of the initial progressive addition lens are calculated. The optimizaiton method can reduce the astigmatism by adding the freeform surface consisting of micro cylinders with different curvatures and different directions. The optimization algorithm and an example are given. An initial progressive addition lens and an optimized lens by this method are manufactured and tested. Compared with the initial lens, the optimized lens has smaller maximum astigmatism value and larger clear region in the distance-vision zone..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1122003 (2012)
Design of 6× Cooled Thermal Imaging Middle Infrared Continuous Zoom Optical System
Zhang Tingcheng, and Liao Zhibo
A new method to solve the zoom equation is presented. For the middle infrared 320×256 element cooled thermal focal plane array detector, an optical system of 3.7～4.8 μm refractive infrared continuous zoom is designed, which has a constant F number of 2, a minimum focal length of 22 mm, and a zoom ratio of 6. This A new method to solve the zoom equation is presented. For the middle infrared 320×256 element cooled thermal focal plane array detector, an optical system of 3.7～4.8 μm refractive infrared continuous zoom is designed, which has a constant F number of 2, a minimum focal length of 22 mm, and a zoom ratio of 6. This system is composed of a zoom objective and a secondary imaging system, including 7 lenses made of silicon or germanium in total. In order to correct off-axis aberrations, aspherical surfaces are used. Meanwhile, two folding mirrors are introduced to reduce the volume of this system. The modulation transfer function of each field of view is above 0.55 in all focal positions at the spatial frequency of 16 lp/mm. The energy permeance ratio is greater than 80% within the inscribed circle limited by the detector sensor with the size of 30 μm×30 μm. So the continuous zoom system has a good imaging quality..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1122004 (2012)
Design of Hybrid Refractive and Reflective Optical System of Long-Wave Infrared Region Imaging Spectrometer
Zhang Xiaolong, Liu Ying, Sun Qiang, Liu Jianzhuo, and Wang Baohua
In order to achieve the long-wave infrared hyperspectral imaging for remote sensing target and to meet the needs of target detection for large amount of information, a long-wave infrared (8~12 μm) imaging spectrometer with high spectral resolution is designed. Off-axis three-mirror system is used in fore telescope systIn order to achieve the long-wave infrared hyperspectral imaging for remote sensing target and to meet the needs of target detection for large amount of information, a long-wave infrared (8~12 μm) imaging spectrometer with high spectral resolution is designed. Off-axis three-mirror system is used in fore telescope system to implement a design of no obscuration, large diameter and wide-viewing-field imaging. The refraction and reflection structure is respectively used in optimizing the spectrophotometric system. The result shows that the optical system with an aperture of 100 mm, F number of 2, spectral resolution of 16 nm, spatial resolution of 150 μrad, cold aperture efficiency of 100% and image quality closing to the diffraction limit can be designed using refractive structure. However, when reflective structure is adopted, multi-chip off-axis mirrors are used to ensure that the optical system has no obscuration, which results in an increase of the asymmetry of the system and makes it difficult to correct the astigmatism, coma and field curvature to the best condition. The design result shows that hybrid refractive and reflective imaging spectrometer has the advantages of high spectral resolution, good image quality, reasonable structure and the match between the root-mean-square (RMS) diameter of point spot and the pixel size of the existing domestic detectors..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1122005 (2012)
Optical Devices
Real-Time Control Technique of Optimal Operating Point in Four-Mode Differential Laser Gyro
Wang Fei, Long Xingwu, and Wang Zhiguo
In order to minimize the bias sensitivity of a four-mode differential laser gyro (FMDLG) to external interference, an optimal operating point real-time control technique is adopted. Dispersion equalization and path-length control offset are used. The magnetic field of gain zone and detune frequency are sinusoidally modIn order to minimize the bias sensitivity of a four-mode differential laser gyro (FMDLG) to external interference, an optimal operating point real-time control technique is adopted. Dispersion equalization and path-length control offset are used. The magnetic field of gain zone and detune frequency are sinusoidally modulated, then the error in the bias of FMDLG is demodulated. By negative feedback it is operated at the only optimal point on which the sensitivity to interference is smallest. The optimal operating point means the minimum bias sensitivity to magnetic field and path-length control error. In comparison with traditional path-length control method, the optimal operating point real-time control technique shows a great reduction of the gyro magnetic sensitivity and bias instability, which proves its effectiveness，and static and dynamic test results prove its correctness..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1123001 (2012)
Quantum Optics
Effect of the Pulse Broadening Caused by Atmosphere on Satellite Based Quantum Key Distribution
Zhao Guhao, Zhao Shanghong, Yao Zhoushi, Meng Wen, Wang Xiang, Zhu Zihang, and Liu Feng
The temporal pulse broadening of cohered laser pulse caused by atmospheric turbulent and dispersion is analyzed. The expression of turbulence-induced and dispersion-induced pulse broadening is given. Based on the measured data of atmospheric parameters and the fitting formula, the relations of pulse broadening to the zThe temporal pulse broadening of cohered laser pulse caused by atmospheric turbulent and dispersion is analyzed. The expression of turbulence-induced and dispersion-induced pulse broadening is given. Based on the measured data of atmospheric parameters and the fitting formula, the relations of pulse broadening to the zenith angle, original pulse and the wavelength of optical signal are obtained．The background noise in satellite-earth quantum key distribution is simulated. The simulation shows that when the wavelength is 1.06 μm and the original pulse is 15 fs, the final pulse has the minimum. For different zenith angle, the background noise is about 1.9×10-10~2.7×10-10, and the quantum error bit rate is about 0.5×10-5..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1127001 (2012)
Study on High-Order Reflective Ghost Imaging with Incoherent Thermal Light
Yang He, and Zhao Shengmei
Most ghost imaging experiments and theories have addressed the transmissive object, which simplifies the procedure of imaging analysis. However, reflective ghost imaging is more valuable in application, such as in the remote sensing technology. The high-order reflective ghost imaging with an incoherent, uniformly brighMost ghost imaging experiments and theories have addressed the transmissive object, which simplifies the procedure of imaging analysis. However, reflective ghost imaging is more valuable in application, such as in the remote sensing technology. The high-order reflective ghost imaging with an incoherent, uniformly bright thermal light is studied. The expressions of the cross-correlation function, image visibility, and signal-to-noise ratio for the high-order reflective ghost imaging is presented. Compared with the results of the second-order reflective ghost imaging, the effect of the order number on the performance of high-order reflective ghost imaging is discussed. The results show that the visibility of high-order reflective ghost imaging is enhanced while the signal-to-noise ratio decreases with the bigger order. And the signal-to-noise ratio can be improved by increasing the measurements in implementation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1127002 (2012)
Entanglement Evolution and Transfer in the Coupled Double Tavis-Cummings Model
Jia Ran, Zhang Yingjie, and Xia Yunjie
The entanglement evolution and transfer of the double Tavis-Cummings model which are connected by the optical fiber are investigated. The results show that the initial entanglement between two atoms can transfer to the other two atoms, and the optical-fiber mode plays a part in transmission during the entanglement tranThe entanglement evolution and transfer of the double Tavis-Cummings model which are connected by the optical fiber are investigated. The results show that the initial entanglement between two atoms can transfer to the other two atoms, and the optical-fiber mode plays a part in transmission during the entanglement transfer process. The entanglement transfer can be influenced by the initial entanglement and the coupling strength not only between atom and cavity but also between optical fiber and cavity. The detuning between atom and cavity field and the cavity dissipation can also have an effect on the entanglement transfer. The initial entanglement can decide the value of generated concurrence, when the coupling strength between atom and cavity field is given, the stronger the coupling strength between optical fiber and cavity is, the shorter time of the entanglement transfer will be and the lager value of generated concurrence entanglement will be. Although the cavity dissipation makes the entanglement decay obviously, the detuning can restrain this phenomenon. During the whole entanglement transfer process, the concurrence between any other two subsystems in the system plays a role of bridge and this system can realize the teleportation and preparation of the bipartite entanglement state..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1127003 (2012)
Remote Sensing and Sensors
Quantitative Research on the Thermal Radiation Polarization Properties of Snow
Zhang Xia, Zhao Yunsheng, Sun Tianlin, and Zhang Lili
As one of the valid sources to measure the global climate changes, snow has its own thermal radiation polarization properties, which are affected by multi-factors. For quantitative analysis of the effects of single factor and the interactions between factors on the thermal radiation polarization properties of snow, on As one of the valid sources to measure the global climate changes, snow has its own thermal radiation polarization properties, which are affected by multi-factors. For quantitative analysis of the effects of single factor and the interactions between factors on the thermal radiation polarization properties of snow, on the basis of traditional analysis, we design a three-factor and three-level orthogonal test. The results show that the detecting angle, azimuth angle and bands have impact on the thermal radiation polarization properties of snow. The detecting angle has high significant impact on the thermal radiation polarization degree of snow. The bands and the interactions of the detecting angle and other two factors significantly affect the thermal radiation polarization degree of snow. The azimuth angle has certain impact on the thermal radiation polarization degree of snow, and its interactions with the bands have no impact on the thermal radiation polarization degree of snow. Therefore, the effects of each single factor and their interactions on the thermal radiation polarization degree of snow should be considered in the research..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1128001 (2012)
Real-Time Pressure Measurements Using Stokes Parameter in Fiber Bragg Gratings and the Performance Analysis
Su Yang, Zhang Baofu, Zhu Yong, Ye Zhenxing, and Peng Hui
A novel real-time pressure measurement using Stokes parameter of fiber Bragg gratings (FBG) in transmission is proposed. It is analyzed that the first Stokes parameter of the transmitted light in FBG has monotonous relationship with linear birefringence induced by pressure. The simulations show that the choices of inciA novel real-time pressure measurement using Stokes parameter of fiber Bragg gratings (FBG) in transmission is proposed. It is analyzed that the first Stokes parameter of the transmitted light in FBG has monotonous relationship with linear birefringence induced by pressure. The simulations show that the choices of incident angle and the wavelength points have an important effect on the sensitivity, the linearity of the sensor and dynamic range. Experimental results obtained on fiber Bragg gratings transversally loaded by an external force confirm the simulated evolutions. The performances are analyzed and the solutions are proposed to improve the system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1128002 (2012)
Measurement of Verdet Constant in Fiber Optical Current Transducer Using an Optimization Method
Zhuang Jing, Xiao Yueyu, Peng Lei, and Yan Jinkui
Verdet constant is one of important parameters which can determine sensitivity of a fiber optical current transducer (FOCT). Calibration signal is calculated based on Sagnac interference principle, and the output signal of FOCT is measured. By comparing above these two sets of signals, an objective function is establisVerdet constant is one of important parameters which can determine sensitivity of a fiber optical current transducer (FOCT). Calibration signal is calculated based on Sagnac interference principle, and the output signal of FOCT is measured. By comparing above these two sets of signals, an objective function is established, and then the parameters of the function are optimized based on a Nelder-Mead simplex method. Thereby the Verdet constant of silica fiber is measured. Experimental results are in good agreement with the results calculated by classical models. Phase delay is added to the output signal when it goes through the measuring circuits. Influenced by rotator and changing environment, the working point of the interference loop drifts. As a result, the output signal becomes asymmetric and creates the direct current quantity. Considering all these situations, the phase delay, working point and direct current quantity which reflects the nonlinear distortion can also be obtained by this method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1128003 (2012)
Simulations of Conjugate Dammann Grating Based on Coherent Beam Combination of Two-Dimensional Solid State Laser Array
Li Bing, Yan Aimin, Dai Enwen, Lü Xiaoyu, Zhi Ya′nan, Sun Jianfeng, and Liu Liren
Conjugate Dammann grating based on coherent beam combining technique that combines and aperture-fills a phase-locked two-dimensional laser array is an effective way to obtain high-power and high-beam-quality laser with single lobe in the far field. Here, this technique is applied to the coherent beam combining of two-dConjugate Dammann grating based on coherent beam combining technique that combines and aperture-fills a phase-locked two-dimensional laser array is an effective way to obtain high-power and high-beam-quality laser with single lobe in the far field. Here, this technique is applied to the coherent beam combining of two-dimensional phase-locked solid-state laser array. Theoretical analysis and experimental verification of a large aperture 5×5 solid-state laser array beam combination are described in detail. The beam combining efficiency of the system is measured. The influence of the manufacturing and positioning error of the grating on the beam combining efficiency is also measured and compared with theoretical analysis. Results show that this technique is very suitable for large-aperture solid-state laser array combination. By adjusting the period of the conjugate Dammann grating and the focal length of the Fourier lens, this technique can be used in systems of different duty circles. It is of great significance to the development of high-power, high-beam-quality solid-state laser systems..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1128004 (2012)
Fiber Bending Sensor Based on LP21 Mode
Fan Yuqiang, Yuan Yufeng, Wei Wanting, Chen Xin, and Wu Xingkun
A novel fiber optic bending sensor based on LP21 mode is developed. A fiber affixed onto an elastic substrate is used to sense bending angles in the real time by measuring rotation of LP21 mode spot image. Theoretical analysis is given by fiber coupled-mode theory combining with elastic-optic theory. Relation between sA novel fiber optic bending sensor based on LP21 mode is developed. A fiber affixed onto an elastic substrate is used to sense bending angles in the real time by measuring rotation of LP21 mode spot image. Theoretical analysis is given by fiber coupled-mode theory combining with elastic-optic theory. Relation between spot-rotation angle and sensor bending angle for different structures and temperatures is tested. The experimental results agree with theoretical analysis and validate the accuracy of the sensor. The sensor is temperature-immune and can detect bending direction as well as bending angles with a large dynamic range..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1128005 (2012)
Mathematical Model of Illumination of CCD in the Space Scanning Optical Fiber Fabry-Pérot Sensor Demodulation System
Meng Xiang′e, Jiang Junfeng, Liu Tiegen, Liu Kun, Yin Jinde, Wang Shaohua, Wang Shuang, Zhang Yimo, Wu Fan, and Qin Zunqi
A mathematical model of charge coupled device (CCD) illumination distribution for spatial scanning optical Fabry-Pérot (F-P) demodulation system is established, and a research on the output signal of CCD and its signal-to-noise ratio (SNR) is made. CCD illumination-distribution experiment is done using the designeA mathematical model of charge coupled device (CCD) illumination distribution for spatial scanning optical Fabry-Pérot (F-P) demodulation system is established, and a research on the output signal of CCD and its signal-to-noise ratio (SNR) is made. CCD illumination-distribution experiment is done using the designed demodulation module. And results show that the relative error between the experimental and calculated values of the CCD output voltage is less than 2.5%, and the change of relative error from the same pixel is less than 0.005 under different frame scan frequencies. The changing rate of SNR is different before and after 184 Hz with the change of frame scan frequency. Experiments are carried out to verify the validity of our established mathematical model..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1128006 (2012)
Two-Viewing Angle Ladar Data Registration Based on Improved Iterative Closest-Point Algorithm
Zhao Mingbo, He Jun, Luo Xiaobo, and Fu Qiang
Two-viewing angle ladar data registration is an important content in the research filed of obscure target detection by air to ground. Iterative closest-point (ICP) algorithm provides the theoretical basis for it. But the corresponding points are difficult to be confirmed in the ICP algorithm due to the complexity of laTwo-viewing angle ladar data registration is an important content in the research filed of obscure target detection by air to ground. Iterative closest-point (ICP) algorithm provides the theoretical basis for it. But the corresponding points are difficult to be confirmed in the ICP algorithm due to the complexity of ladar data in the obscure condition. Based on the analysis of ICP algorithm fundamental principle and ladar data characteristics in the obscure condition, the application strategies and improvements of the ICP algorithm are proposed in three aspects, which are the support-points selecting, corresponding points matching and the pseudo-points removing. Moreover, a novel pseudo-points removing algorithm is proposed based on a fixed-adaptive overlap rate. Then the concrete steps of two-viewing angle ladar data registration using the improved ICP algorithm are elaborated, and lastly the experimental verification is carried out. The experimental results show that the improved ICP algorithm can effectively register the ladar data in the obscure condition, and has stronger robustness and higher registration accuracy compared with other algorithms..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1128007 (2012)
Spectroscopy
Numerical Simulation of Terahertz Transmission through Rectangular Hole of Metallic Structure on Substrate with Different Thicknesses
Zhang Gaohui, and Zhao Guozhong
The terahertz transmission characteristics of the rectangular-hole metal structure on different materials and thicknesses of substrates are studied based on the finite difference time domain method. The results show that there exists the frequency selectivity in THz transmission spectrum of the rectangular-hole metalliThe terahertz transmission characteristics of the rectangular-hole metal structure on different materials and thicknesses of substrates are studied based on the finite difference time domain method. The results show that there exists the frequency selectivity in THz transmission spectrum of the rectangular-hole metallic structure. The frequency selectivity provides the basis of the terahertz filter. In practical applications, these metallic microstructures often need to be deposited on the substrates. Obviously, the substrate material and its thicknesses have influence on the terahertz transmission characteristics of metallic microstructures. We investigate how the different substrate materials and its thicknesses affect the terahertz transmission of entire structure. By numerical simulation, it is found that the transmission peak shifts into the lower frequency with increasing of the substrate thicknesses. Comparing Si and polytetrafluoroethylene (PTFE) as the substrate materials, it is shown that peak shift of Si substrates with high dielectric constant is more obvious..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1130001 (2012)
Extraordinary Transmission Properties of Gold Aperture Array-Dielectric and Gold-Dielectric Aperture Array
Yang Hongyan, and Xiao Gongli
The effects of gold film thickness, refractive index of dielectric and its thickness on extraordinary transmission properties of gold aperture array-dielectric and gold-dielectric aperture array are studied using the finite-difference time-domain (FDTD) method. The results show that both structures have a good extraordThe effects of gold film thickness, refractive index of dielectric and its thickness on extraordinary transmission properties of gold aperture array-dielectric and gold-dielectric aperture array are studied using the finite-difference time-domain (FDTD) method. The results show that both structures have a good extraordinary transmission property, which suggests that surface plasmon polariton (SPP), formed by coupling of light and free electron charge density wave of gold film surface, plays a key role in enhanced transmission. The gold film thickness is the major factor affecting the extraordinary transmission property, and its decay length is 35 nm; the thickness of dielectric film adjacent to the gold film has minimal impact on the extraordinary transmission property. The refractive index of dielectric has a distinct impact on the extraordinary transmission property, and the refractive index of 1.8 may lead to a good extraordinary transmission property..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1130002 (2012)
Design of Dyson Concentric Optical Hyperspectral Imaging System with Achromatized Féry Prism
Yang Jin, Tang Yuguo, Bayanheshig, Cui Jicheng, and Qi Xiangdong
In order to achieve the requirements of miniaturization, light weight, high image quality of the hyperspectral imaging system, and improve the optical efficiency for the whole spectral range, the Dyson hyperspectral imaging system with achromatized Féry prism is presented. To decrease the nonlinear dispersion of sIn order to achieve the requirements of miniaturization, light weight, high image quality of the hyperspectral imaging system, and improve the optical efficiency for the whole spectral range, the Dyson hyperspectral imaging system with achromatized Féry prism is presented. To decrease the nonlinear dispersion of spectrum, the achromatized prisms are introduced into the system. The optical modulation transfer function (MTF) for visible-near infrared (VNIR) spectral channel is higher than 0.9, and the spectral resolution is about 4.2～6.8 nm. The MTF for short-wave infrared (SWIR) spectral channel is 0.73～0.87, and the spectral resolution is about 6.4～12.5 nm. The achromatized Féry prisms correct the spectral-line bending and color distortion of the two hyperspectral imaging systems. Optical simulation shows that the distortion is less than 0.13% and the spectral bend is less than 0.05%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1130003 (2012)
Thin Films
Dependence of Optical Constants and Optical Band Gap on Thickness of Antimony-Based Bismuth-Doped Film at Near-Infrared Region
Lu Xinmiao, Jiang Laixin, Wu Yiqun, and Wang Yang
Antimony-based bismuth-doped films with different thicknesses are deposited by magnetron sputtering method. The structure of samples with different thickness is studied by X-ray diffraction (XRD) and transmission electron microscope (TEM). The optical constants and optical band gap of the samples in range of 950～2200 nAntimony-based bismuth-doped films with different thicknesses are deposited by magnetron sputtering method. The structure of samples with different thickness is studied by X-ray diffraction (XRD) and transmission electron microscope (TEM). The optical constants and optical band gap of the samples in range of 950～2200 nm are measured by spectroscopic ellipsometry. The influence of thickness on optical constants and optical band gap is investigated. The results show that the structure of the samples transforms from amorphous state into crystalline state when the thickness increases from 7 nm to 100 nm. In wavelength range of 950～2200 nm, the refractive index, extinction coefficient and optical band gap of the samples with different thickness are in range of 4.6～8.9, 0.6～5.8 and 0.32～0.16 eV, respectively. The refractive index and optical band gap decrease and the extinction coefficient increases with the increase of thickness. At thickness of 50 nm, the optical constants have a critical value, which results from the change of microstructure when thickness is larger or smaller than the critical value..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 11, 1131001 (2012)
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