Contents
2008
Volume: 28 Issue 5
38 Article(s)
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Atmospheric Optics and Oceanic Optics
Atmospheric Correction of QuickBird-2 Imagery for Turbid Water Coastal Areas Using MODIS Data
Peng Nina, Yi Weining, Ma Jinji, and Fang Yonghua
Atmospheric correction is an important part of the Quantitative Remote Sensing, and the most important key for atmospheric correction is Aerosol retrieval including Aerosol optical depth, Aerosol type and atmospheric diffuse transmission. But to retrieve the aerosol optical character over the turbid waters is difficultAtmospheric correction is an important part of the Quantitative Remote Sensing, and the most important key for atmospheric correction is Aerosol retrieval including Aerosol optical depth, Aerosol type and atmospheric diffuse transmission. But to retrieve the aerosol optical character over the turbid waters is difficult by using satellite image itself. So we advanced an atmospheric correction algorithm of QuickBird-2 imagery for turbid water coastal areas using synchronous measuring MODIS data. This algorithm is to retrieve the atmospheric properties of turbid water coastal areas based on MODIS water pixel. The relative error between the retrieval result and the MODIS aerosol product is less then 10%. On the other hand, by using the 6s Radiation Transfer Model and taking account of the adjacency effect for high spatial resolution imagery, Atmospheric correction has been applied to QuickBird-2 imagery for turbid water coastal areas. The atmospheric correction results and the analysis of retrieval errors have been given..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 817 (2008)
Diffraction and Gratings
Study of Grating Diffractive Field's Degree of Polarization and Angular Coherence of Partially Polarized and Coherent Beams
Xiao Qinggang, Xiao Yao, and Zeng Yangsu
In order to study the grating diffractive field's characteristics of the partially polarized and coherent beams, an analytic expression of polarization degree and angular correlation of partially ploarized and coherent beams through polarized gratings is derived based on the beam coherentce-polarization (BCP) matriIn order to study the grating diffractive field's characteristics of the partially polarized and coherent beams, an analytic expression of polarization degree and angular correlation of partially ploarized and coherent beams through polarized gratings is derived based on the beam coherentce-polarization (BCP) matrix approach of partially coherent beams. And then the partially polarized and coherent Gausian-Schell beam (PGSM) is taken as a numerical example to study the influence of the polarized grating TE and TM complex transmission and some parameters of the incident PGSM on the polarization degree of the diffraction field and the diffractive orders's angular correlation in details. It is shown that the PGSM's diffractive field is an uneven and periodically changed partially coherent field, and the symmetrical diffraction order's angular coherence is equal and decreases to zero along with the increase of diffraction orders..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 822 (2008)
Fiber Optics and Optical Communications
Research on Optical Fiber Grating Chirp-Sensing Technology
Guo Tuan, Liu Bo, Zhang Weigang, Kai Guiyun, Zhao Qida, and Dong Xiaoyi
The concept and principle of optical fiber grating chirp-sensing technology are proposed. The spatially varying structure of the chirped fiber grating has been divided into several sections called the effective-interaction sub-regions. Each effective-interaction sub-region prossesses an independent sensing ability and The concept and principle of optical fiber grating chirp-sensing technology are proposed. The spatially varying structure of the chirped fiber grating has been divided into several sections called the effective-interaction sub-regions. Each effective-interaction sub-region prossesses an independent sensing ability and its relationship to the gradient distribution of environmental parameters has been formulated. The origin of the FBG chirping and its effect on the characteristics of the resultant reflection spectra (wavelength, bandwidth and total optical power) under the effect of the surrounding environment (spatial distributions of temperature and strain) have been theoretically explained and experimentally demonstrated. This provides the foundation of the FBG chirp-sensing technology and opens new avenues for its potential applications in simultaneous measurement of multiple parameters and also in the distributed measurement of nonuniform environmental parameters..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 828 (2008)
Parallel Buffering of Dual-Wavelength Packets Data
Peng Peng, Wu Chongqing, Tian Changyong, Li Yajie, and Guo Ning
A 2.5 Gb/s dual-wavelength packets parallel buffering in dual-loop optical buffer (DLOB) adopting semiconductor optical amplifier (SOA) as the nonlinear element was demonstrated. Because of the random fluctuation of the combined power by different wavelength signals, the phase difference originating from the cross phasA 2.5 Gb/s dual-wavelength packets parallel buffering in dual-loop optical buffer (DLOB) adopting semiconductor optical amplifier (SOA) as the nonlinear element was demonstrated. Because of the random fluctuation of the combined power by different wavelength signals, the phase difference originating from the cross phase modulation of SOA fluctuates randomly too. Taking the absorption loss into account, we modify the gain characteristic curve of SOA and fit it with experimental values. The characteristic curve is described exactly. We also theoretically analyze the dual-wavelength buffering and propose to set the power of control signal to minimize the fluctuation of the phase difference..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 835 (2008)
Modified Rouard Method for Fiber Bragg Grating Fabry-Pérot Cavity
Wang Yanhua, Liu Yan, Tan Zhongwei, Ren Wenhua, and Jian Shuisheng
The limit method, balance method and transfer matrix method for fiber Bragg grating (FBG) Fabry-Pérot (F-P) cavity are studied and proved uniform. The influence of the reflection phase of fiber Bragg grating complex amplitude transfer matrix on the transmission of fiber Bragg grating Fabry-Pérot cavity is empThe limit method, balance method and transfer matrix method for fiber Bragg grating (FBG) Fabry-Pérot (F-P) cavity are studied and proved uniform. The influence of the reflection phase of fiber Bragg grating complex amplitude transfer matrix on the transmission of fiber Bragg grating Fabry-Pérot cavity is emphasized. The Rouard method, which is capable of calculating fiber Bragg grating with arbitrary refractive index modulation, is used to calculate fiber Bragg grating Fabry-Pérot cavity and modified by introducing initial phase of refractive index distribution to calculate the reflection phase precisely. The transmission spectrum of fiber Bragg grating Fabry-Pérot cavity with multi-peak structure is obtained with the above results and the calculation results are proved by experiments..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 840 (2008)
Two-Ring-Resonantor in Parallel Combined Rayleigh Backscattering Fiber Optic Gyroscope
Liu Yanlei, Yuan Libo, and Zhou Ai
A novel two-ring-resonantor in parallel combined Rayleigh backscattering fiber optic gyroscope (RBFOG) is proposed based on the single ring scheme. The theoretical model of the two-ring combined RBFOG is established by using two 2×2 fiber star coupler. The expression of detection signal intensity is deduced. The oA novel two-ring-resonantor in parallel combined Rayleigh backscattering fiber optic gyroscope (RBFOG) is proposed based on the single ring scheme. The theoretical model of the two-ring combined RBFOG is established by using two 2×2 fiber star coupler. The expression of detection signal intensity is deduced. The output signal characteristics are analyzed by optimizing the structure parameters of the two-ring cavity lengths and coupling ratios. The experimental system is constructed with cavity lengths of 1500 m and 1078 m at coupling ratios of 95.23% and 94.88% respectively. Rayleigh backscattering signals are measured at different rotation rate by OTDR. Feasibility of the novel structure is validated. Compared with single-ring RBFOG, the two-ring system increases measuring effective data, and is propitious to recognize, and the measuring precision is improved..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 846 (2008)
High-Accuracy Real Time Calibration of Tunable Fabry-Pérot Filter on Large Range
Qiao Xueguang, Wang Yu, Fu Haiwei, Zhao Dazhuang, Wang Wei, and Zhang Jing
Absorption spectrum of acetylene (C2H2) is used as the wavelength reference to calibrate the tunable fiber Fabry-Pérot (TFFP) filter in real time, and the accuracy of interrogation system based on TFFP has been improved. According to the free spectrum periodic characteristic of TFFP, a method to increase the wavelAbsorption spectrum of acetylene (C2H2) is used as the wavelength reference to calibrate the tunable fiber Fabry-Pérot (TFFP) filter in real time, and the accuracy of interrogation system based on TFFP has been improved. According to the free spectrum periodic characteristic of TFFP, a method to increase the wavelength calibration range was proposed. The system has a resolution of 1 pm over a working range of 1525～1615 nm in experiment. Compared with many traditional wavelength reference methods, this interrogation method is greatly improved in measurement precision, wavelength range and working reliability..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 852 (2008)
Image Processing
Zero-Order Image Elimination in Digital Hologram Based on Finite Impulse Response Filter
Liu Wenwen, Dai Yiquan, Kang Xin, Yang Fujun, and He Xiaoyuan
Aiming at the zero-order image's effect on the quality of reconstructed images in digital holography, by analysis of spectrum characteristic as well as recording and reconstruction theory, a method of zero-order image elimination in digital holography by using of finite impulse response (FIR) filter is proposed. ThAiming at the zero-order image's effect on the quality of reconstructed images in digital holography, by analysis of spectrum characteristic as well as recording and reconstruction theory, a method of zero-order image elimination in digital holography by using of finite impulse response (FIR) filter is proposed. The method is based on only one hologram and the digital image processing for preprocessing the digital hologram in spatial domain to eliminate the zero-order image, free of phase modulator or any other extra-equipment. The comparison of elimination zero-order image in reconstructed hologram before and after using FIR filter in digital simulation and experiment presents that this method can eliminate the zero-order image and enhance the quality of reconstructed image with a simple algorithm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 856 (2008)
Infrared Target Tracking Algorithm Based on Algorithm Fusion
Guan Zhiqiang, Chen Qian, Qian Weixian, and Hu Yongsheng
The difficulty in video tracking is how to find the matching points of target from flame to frame accurately and reliably. Because of the low contrast between infrared target and background, the blurred edge and low dynamic range of grey lever, the infrared target tracking is more difficult than visible target. An infrThe difficulty in video tracking is how to find the matching points of target from flame to frame accurately and reliably. Because of the low contrast between infrared target and background, the blurred edge and low dynamic range of grey lever, the infrared target tracking is more difficult than visible target. An infrared target tracking algorithm is proposed based on histograms and moment invariant. We use the mean shift algorithm based on histogram to calculate the suboptimal matching point rapidly and efficiently. Because the histogram does not contain the target′s shape features, the suboptimal matching point always has some errors. These errors should be amended to avoid accumulating tracking-error and the tracking-point drifting away from the object gradually. So moment invariant is used to modify these errors and improve the tracking stability and accuracy. Experimental results show that this algorithm is able to eliminate drifting phenomenon and enhance the tracking stability and accuracy..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 860 (2008)
Algorithm for Infrared Image Noise Filtering Based on Anisotropic Diffusion
Bai Junqi, and Chen Qian
To achieve better infrared focal plane array (IRFPA) noise suppression with minimum edge blurring, an anisotropic filtering algorithm is proposed based on Tukey model. This algorithm distills edge by differential, and then the image preprocessing is carried out to improve ill-posed problem of Perona-Malik (P-M) equatioTo achieve better infrared focal plane array (IRFPA) noise suppression with minimum edge blurring, an anisotropic filtering algorithm is proposed based on Tukey model. This algorithm distills edge by differential, and then the image preprocessing is carried out to improve ill-posed problem of Perona-Malik (P-M) equation based on the distribution properties of signal and noise. A new diffusion coefficient was established to satisfy Charbonnier rule. Initialized edge conditions are presented to preserve edge. It has run on the DSP+FPGA platform, and has good effect in the respect of noise removal and edge preservation. The visual effect of the treated image is promoted..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 866 (2008)
Imaging Systems
Extension Ratio of the Depth of Field for Wavefront Coding Imaging System
Pan Chao, Chen Jiabi, Zhang Rongfu, and Zhuang Songlin
By studying the optical transfer function (OTF) of wavefront coding (WFC) imaging system with cubic phase mask, we find that modulation transfer function (MTF) of WFC system is defocus-independent under a special condition. Compared with the traditional optical system, a formula of extension ratio of the depth of fieldBy studying the optical transfer function (OTF) of wavefront coding (WFC) imaging system with cubic phase mask, we find that modulation transfer function (MTF) of WFC system is defocus-independent under a special condition. Compared with the traditional optical system, a formula of extension ratio of the depth of field (DoF) for WFC imaging system is obtained. Through analyzing the range of spatial frequency and the coefficient of phase term α, the conclusion is drawn that the DoF of WFC imaging system can be extended more than 60 times when α＝20π..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 870 (2008)
Instrumentation, Measurement and Metrology
A New Method for Phase Retrieval on Non-Monotonous Fringes
Sun Wei, He Xiaoyuan, and Quan Chenggen
A novel method based on continuous wavelet transform (CWT) and guidance of inflexion points of unwrapped phase is developed to measure the phase of non-monotonous fringes. Wrapped phase values are retrieved by ridge extraction algorithms based on CWT. To increase the resolution of measurement and reduce the noise, the A novel method based on continuous wavelet transform (CWT) and guidance of inflexion points of unwrapped phase is developed to measure the phase of non-monotonous fringes. Wrapped phase values are retrieved by ridge extraction algorithms based on CWT. To increase the resolution of measurement and reduce the noise, the scale incremental step is determined by a proper criterion and the scales detected by maximum ridge algorithm are filtered iteratively before retrieval of wrapped phase. Based on the homography relationship between an inflexion point and an ambiguous point, the real phase values can be retrieved by directly identifying any inflexion point from an unwrapped phase map without the use of a carrier. The proposed method is analyzed theoretically in great details. Furthermore, the algorithm developed is validated by computer simulation, which includes one-dimensional and two-dimensional cases both with and without noise, and an experiment based on micro interferometry. Simulations and experimental results for both static and dynamic shapes and deformations of a micro structure demonstrate that the proposed method is effective for the analysis of a closed fringe pattern and subsequent deformation measurement, which has the capability of high accuracy and good noise reduction with a maximum error less than 4%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 876 (2008)
Approach to Accuracy Evaluation for Subaperture Stitching Interferometry
Chen Shanyong, Dai Yifan, Xie Xuhui, and Ding Lingyan
As a high-precision testing method for optical surfaces, accuracy of the subaperture stitching interferometry is very important and must be evaluated quantitatively. The contrast test approach is proposed to evaluate the measurement accuracy with the full aperture test taken as a reference. Then the figures of merit asAs a high-precision testing method for optical surfaces, accuracy of the subaperture stitching interferometry is very important and must be evaluated quantitatively. The contrast test approach is proposed to evaluate the measurement accuracy with the full aperture test taken as a reference. Then the figures of merit as well as their computing methods are discussed. Since the geometrical parameters are different in the full aperture test and the subaperture stitching test, optimal matching is proposed between the two test results. The principle resembles that of the subaperture stitching algorithm. The figures of merit are computed following the matching process. Finally experiments are presented, and the results show the figure of merit with matching is reduced by about 48% of that without matching, which proves the validity of the approach for quantitative accuracy evaluation of subaperture stitching interferometry..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 883 (2008)
Linearity Measurement of Accurate Photodetector
Chen Feng, Li Shuang, Wang Ji, and Zheng Xiaobing
A linearity measurement systems of accurate photodetector is described. The principle of linearity measurement methods is dicussed, and the beam-addition method is used in this measurement system. Structure of measurement system is designed, and the linearity measurement of Si trap photodetector and InGaAs trap photodeA linearity measurement systems of accurate photodetector is described. The principle of linearity measurement methods is dicussed, and the beam-addition method is used in this measurement system. Structure of measurement system is designed, and the linearity measurement of Si trap photodetector and InGaAs trap photodetector is done with 944 nm laser. Experimental results show in the range of laser power (0.1～200 μW), the measured nonlinearity factor of Si trap photodetector is less than 0.009%, and its combined uncertainty is less than 3.18%, the measured nonlinearity factor of InGaAs trap photodetector is less than 0.6%, and its combined uncertainty of measurement is less than 6.87%. Experimental results prove that the system can be used in accurate photodetector’s linearity measurement..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 889 (2008)
Three-Dimensional Rigid Body Displacement Measurement Based on Digital Image Correlation
Sun Wei, He Xiaoyuan, Quan Chenggen, and Zheng Xiang
Owing to the necessity and importance of the three-dimensional (3-D) displacement measurement technique in the field of engineering, a system based on a single CCD camera and a method of digital image correlation is developed. With regard to the relationship between the center and the slope of the displacement vector aOwing to the necessity and importance of the three-dimensional (3-D) displacement measurement technique in the field of engineering, a system based on a single CCD camera and a method of digital image correlation is developed. With regard to the relationship between the center and the slope of the displacement vector and displacements in and out-of the object plane, a least-squares fit method is employed to calculate constant terms (corresponding to the in-plane component) and the first order terms (corresponding to the out-of-plane component), and the three-dimensional displacement components are separated. On the theoretical basis of the pin-hole camera imaging model, a numerical simulation and an experiment on three-dimenaional translation of a silicon wafer are conducted. The simulation method of speckle images associated with the three-dimensional rigid body displacement is developed, which is further employed to validate the effectiveness and precision of the iterative correlation method based on affine transformation. Simulated and experimental results demonstrate that both in-plane and out-of-plane displacements can be accurately retrieved with the proposed method, and the maximum error is 5%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 894 (2008)
Wavelength Calibration of Shortwave Infrared Flat Spectroradiometer
Li Xin, Zhang Guowei, Xun Lina, Xie Ping, Hong Jin, and Zheng Xiaobing
The wavelength calibration methods were investigated for shortwave infrared (SWIR) flat spectroradiometer. The shortwave infrared spectroradiometer includes two measurement units. The unit based on a concave holograph grating, has a flat focal plane along which a photodiode array (PDA) is placed. The wavelength calibraThe wavelength calibration methods were investigated for shortwave infrared (SWIR) flat spectroradiometer. The shortwave infrared spectroradiometer includes two measurement units. The unit based on a concave holograph grating, has a flat focal plane along which a photodiode array (PDA) is placed. The wavelength calibration is performed in each respective band. In order to calibrate more accurately, calibration process is designed in accordance with the spectroradiometer characters. For wavelength calibration, the light source of fine spectral line becomes important. We select monochromator as light source which outputs light with spectral resolution of 1.5 nm in shortwave range. In this way, we preliminarily decide which pixel a spectral line is located at. Next, the position of the peak wavelength is determined by the center of gravity method. Then, the coefficients of polynomial curve are decided through data fitting. The calibration results show that in the range of 900～2400 nm the fitting error is less than 0.5 nm and calibration uncertainty better than 0.6 nm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 902 (2008)
Simultaneous Three-Dimensional Environment Reconstruction and Localization based on Monocular Vision
Shen Yehu, Liu Jilin, and Du Xin
Simultaneous localization and mapping (SLAM) is one of the most important components in robot navigation. A novel SLAM algorithm based on monocular vision is proposed to overcome the difficulties in outdoor applications and quantitative analysis with traditional methods. Firstly, a key frame selection method is proposeSimultaneous localization and mapping (SLAM) is one of the most important components in robot navigation. A novel SLAM algorithm based on monocular vision is proposed to overcome the difficulties in outdoor applications and quantitative analysis with traditional methods. Firstly, a key frame selection method is proposed to reduce the computational cost. Then the three-dimensional (3-D) structure of the environment and the positions of the camcorder are estimated based on matched feature points and the intrinsic parameters of the camcorder. A simple method with reasonable optimizing effect and computing cost is applied to get position and orientation of the camcorder. Finally, an adaptive bundle adjustment is adopted to optimize the 3D structure of the environment and the positions of the camcorder simultaneously. Digital elevation map (DEM) which is more suitable for robot navigation is also obtained. Quantitative and qualitative experimental results show that the loop closure error is less than 4%. The algorithm can reconstruct the environment and localize the camcorder accurately in nearly real time..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 907 (2008)
Lasers and Laser Optics
Electro-Optical Crystal Tuned External Cavity Diode Laser
Xu Zhen, Zhou Shuyu, and Wang Yuzhu
A method of fast laser frequency tuning and frequency modulation by electro-optical crystal is reported. Due to the electro-optical effect of LiNbO3 crystal, fast laser frequency tuning and modulation of the Littrow type external cavity diode laser(ECDL) with an electro-optical crystal is demonstrated by changing the eA method of fast laser frequency tuning and frequency modulation by electro-optical crystal is reported. Due to the electro-optical effect of LiNbO3 crystal, fast laser frequency tuning and modulation of the Littrow type external cavity diode laser(ECDL) with an electro-optical crystal is demonstrated by changing the effective laser cavity length with the voltage on the crystal. By this method, in the homemade ECDL, the tuning range of 350 MHz is achieved with tuning rate of 2 kHz, the tuning coefficient is about 1.06 MHz/V, and the effect of laser tuning was observed by saturated absorption spectrum. The fast frequency modulation can be used on the frequency stabilization. The dispersion signal of the saturated absorption spectrum of D2 line of 87Rb atoms is achieved with the laser frequency modulation rate of 5～100 kHz, and the laser frequency is long-term stabilized on the peak and cross peak of saturated absorption spectrum of the D2 line of 87Rb atoms..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 915 (2008)
Dual-Wavelength Er-Doped Fiber Laser Based on Phase Sampled Fiber Bragg Grating
Ji Heng, Yang Sigang, Zhang Ye, and Xie Shizhong
A dual-wavelength distributed feedback (DFB) fiber laser based on phase sampling is proposed and demonstrated. Change of phase and sampling period is introduced at different positions along a sampling Bragg grating. It is demonstrated theoretically that this structure can provide separate resonant cavities to overcome A dual-wavelength distributed feedback (DFB) fiber laser based on phase sampling is proposed and demonstrated. Change of phase and sampling period is introduced at different positions along a sampling Bragg grating. It is demonstrated theoretically that this structure can provide separate resonant cavities to overcome mode competition caused by gain homogeneous broading. A 0.46 nm-spaced dual-wavelength DFB fiber laser is achieved on an Er-doped fiber with excimer laser and homogeneous phase plate. Experiments shows that dual-wavelength lasing is achieved and laser power is in reverse proportion with coupling coefficient of the FBG..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 919 (2008)
Experiment of Coherence-Locking of Two Photonic Crystal Fiber Lasers
Li Jianfeng, Duan Kailiang, Wang Jianming, Wang Yishan, Zhao Wei, and Guo Yongkang
Beam coherent combination of two photonic crystal fiber (PCF) lasers is experimentally studied by using self-imaging resonator technique, and phase-locking of the two PCF lasers is achieved. Clear and stable interference strips are observed even without a filter in high-power operation and in environmental noise conditBeam coherent combination of two photonic crystal fiber (PCF) lasers is experimentally studied by using self-imaging resonator technique, and phase-locking of the two PCF lasers is achieved. Clear and stable interference strips are observed even without a filter in high-power operation and in environmental noise condition. The advantages of PCF laser in coherent combination over the conventional double-cladding fiber (DCF) are demonstrated. Experiments also show that the reflectivity of coupling output mirror affects coherent output power. The slope efficiencies of two PCF lasers running in in-phase mode are 63.8%, 61.6% and 60.2% for the reflectivity 5%, 10% and 15% of the reflector, respectively. The maximum coherent output power of 95.8W and the combination efficiency of 90.2% are obtained when the pump power is 150 W for the reflectivity of 5%. No thermo-optical problems occur during the experiments, which means that a higher coherent power can be further achieved by using this technique..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 923 (2008)
Materials
Study on Spectral Properties of a New Tricyanofuran Derivative
Han Likun, Jiang Yadong, Li Wei, Hao Peng, Li Chen, and Li Yuanxun
A new D-π-A type of tricyanofuran derivative (DCDHF-2-V) with a novel electron donor was synthesized. The heterocyclic compound-in-poly (methymethacrylate) (PMMA) film was then fabricated by means of the spin-coating method, and its photophysical properties in the solutions and thin film were investigated by UV-vis absA new D-π-A type of tricyanofuran derivative (DCDHF-2-V) with a novel electron donor was synthesized. The heterocyclic compound-in-poly (methymethacrylate) (PMMA) film was then fabricated by means of the spin-coating method, and its photophysical properties in the solutions and thin film were investigated by UV-vis absorption spectra and fluorescence emission spectra. The results show that compared with the absorption spectrum of the compound in solution, the absorption maximum of the film is shifted to some extent, and the absorption band becomes broader. It is found that the maximum peak wavelength of fluorescence spectra, fluorescence quantum yield, and Stocks shift change along with the variation of the polarity of solvent. Moreover, the difference in the dipole moment between the ground and excited states was obtained to be 35.68×10-30 C·m. And the second-order polarizability value of DCDHF-2-V was estimated based on the quantum-mechanical two-level model and its calculated value was 3323.4×10-40 m4/V at the wavelength of 1064 nm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 927 (2008)
Investigations of Optical and EPR Spectra for NiX2(X=Cl,Br,I) Crystals
Feng Wenlin, and Zheng Wenchen
The formulae of optical spectral energy levels and electron paramagnetic resonance (EPR) spectra of all configurations in trigonal symmetry of 3d2(3d8) ions are established on basis of strong field coupling mechanism by using the two-spin-orbit-coupling parameter model. Compared with the classical crystal-field approacThe formulae of optical spectral energy levels and electron paramagnetic resonance (EPR) spectra of all configurations in trigonal symmetry of 3d2(3d8) ions are established on basis of strong field coupling mechanism by using the two-spin-orbit-coupling parameter model. Compared with the classical crystal-field approach which has only taken the spin-orbit coupling of the central transition-metal ions into account, the contribution of the spin-orbit coupling of the ligand ions to the optical and EPR spectra has been included in these formulae. When the optical and EPR spectra of the strong covalent crystals are calculated, reasonable results can be obtained if the two-spin-orbit-coupling parameter model has been put into action. As an application, the optical and EPR spectra of the NiX2(X=Cl,Br,I) crystals have been studied by the complete diagonalization method. The calculated results are in good agreement with experimental findings. From the investigation, a valid method to calculate the optical and EPR spectra of all configurations more accurately is provided..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 932 (2008)
Effect of Temperature on Transmission Properties in Photonic Crystal Fibers Infiltrated With Liquid Crystal
Qian Xiangzhong
Thermally tunable photonic crystal fibers (PCF) are proposed by filling the air hole of PCF core with nematic liquid crystal (LC) and using the LC refractive index change with temperature and wavelength, due to index sensitive to temperature and wavelength. The effect of temperature on PCF transmission properties is stThermally tunable photonic crystal fibers (PCF) are proposed by filling the air hole of PCF core with nematic liquid crystal (LC) and using the LC refractive index change with temperature and wavelength, due to index sensitive to temperature and wavelength. The effect of temperature on PCF transmission properties is studied by the step effective index model and numerical calculation. The results show that dispersion decreases in the PCF infiltrated with liquid crystals, and the PCF appears as single-mode transmission in long wavelength but not in short wavelength, and non-cutoff-wavelength single-mode transmission does not appear even if relative hole diameters in cladding are very small. The dispersion increases and zero dispersion wavelengths shift towards short wavelengths when temperature increases in the PCF. The properties are valuable for design and application of temperature tunable PCF device..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 988 (2008)
Medical Optics and Biotechnology
Analysis of Relationship between Region of Iris and the Accuracy Rate
Yuan Weiqi, Bai Yun, and Ke Li
When people open their eyes normally, the regions of iris will be covered by eyelids and eyelashes. We investigate the performance of the use of a partial iris for recognition by using normalized correlation matching method in different iris image databases. The experimental results show that the inner rings of the iriWhen people open their eyes normally, the regions of iris will be covered by eyelids and eyelashes. We investigate the performance of the use of a partial iris for recognition by using normalized correlation matching method in different iris image databases. The experimental results show that the inner rings of the iris over 37.5% of iris pattern exposure,or the angle of the sector exposed over 70° would be necessary for enough information in human verification. The results also show the curve of the relationship between percentage of the iris used and the accuracy rate..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 937 (2008)
Pathological Changes of Human Bladder Mucosa/Submucosa Tissues Induced Changes in Diffuse Reflection Spectra of Tissues in Vitro
Wei Huajiang, Guo Zhouyi, Xie Shusen, Wu Guoyong, Lu Jianjun, Chen Xuemei, and He Bohua
Diffuse reflection spectra and their differences of normal human bladder and superficial human bladder cancer mucosa/submucosa tissues were studied in the spectral range from 300 nm to 900 nm in vitro. Diffuse reflection spectra of tissues were measured with a spectrophotometer with an integrating sphere attachment. ThDiffuse reflection spectra and their differences of normal human bladder and superficial human bladder cancer mucosa/submucosa tissues were studied in the spectral range from 300 nm to 900 nm in vitro. Diffuse reflection spectra of tissues were measured with a spectrophotometer with an integrating sphere attachment. The results of measurement show that diffuse reflection of normal bladder mucosa/submucosa tissue at each wavelength is obviously higher than that of superficial bladder cancer mucosa/submucosa tissue at the corresponding wavelength. The peaks in diffuse reflection spectra for normal bladder mucosa/submucosa tissues were 52.4% at 370 nm, 60.7% at 520 nm, 56.1% at 550 nm and 75.5% at 660 nm, respectively, while the peaks in diffuse reflection spectra for superficial bladder cancer mucosa/submucosa tissues were 43.7% at 320 nm, 33.4% at 520 nm, 30.6% at 550 nm and 70.2% at 660 nm, respectively. There was a peak in diffuse reflection spectra for normal bladder mucosa/submucosa tissues at 370 nm, and there was not a peak for superficial bladder cancer mucosa/submucosa tissues at 370 nm. There was a peak in diffuse reflection spectra for superficial bladder cancer mucosa/submucosa tissues at 320 nm, and there was not a peak for normal bladder mucosa/submucosa tissues at 320 nm. Pathological changes of bladder mucosa/submucosa tissues induce the decrease of the peak values in diffuse reflection spectra for tissues of 45.0% at 520 nm, 45.5% at 550 nm, and 7.02% at 660 nm. The results show that pathological changes of bladder mucosa/submucosa tissues induce changes in the component and structure of tissues, and especially quantitative changes in oxyhemoglobin and de-oxyhemoglobin of tissues obviously..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 943 (2008)
Position Tolerance Analysis for Wavefront Aberrations Correction of Human Eyes
Zhao Haoxing, and Xu Bing
The tolerance analysis of the compensating devices used to correct the aberrations of human eyes is important. Based on the exact measurements of three human eyes aberrations with Hartmann-Shack sensor, the differences of compensating effect of the high-order aberrations correcting devices and conventional low-order abThe tolerance analysis of the compensating devices used to correct the aberrations of human eyes is important. Based on the exact measurements of three human eyes aberrations with Hartmann-Shack sensor, the differences of compensating effect of the high-order aberrations correcting devices and conventional low-order aberrations correcting devices are compared with lateral displacements and in-plane rotations. The position tolerance of the rotation is better than that of the translation, and the three subjects have similar rotation tolerance about 20° and quite different translation tolerance. The results suggest that the compensating effect depends on both the particular aberrations of each subject and the kind and the amount of misalignment. The bigger wavefront aberration is, the more unconspicuous correcting effect of high-order compensating devices is. For high-order compensating devices, different type of position change is with different tolerance, and rotation has a larger movable tolerance than displacement..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 949 (2008)
Common Path Optical Coherence Tomographic System Suitable for Endoscopic Imaging
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
A Fizeau interferometer based optical coherence tomographic (OCT) system using a fibre-based Michelson interferometer to compensate the optical path difference between the reference and sample light in the Fizeau interferometer is presented. The sensing probe of the system is a common path interferometer which can solvA Fizeau interferometer based optical coherence tomographic (OCT) system using a fibre-based Michelson interferometer to compensate the optical path difference between the reference and sample light in the Fizeau interferometer is presented. The sensing probe of the system is a common path interferometer which can solve the problems existing in current endoscopic OCT systems, such as image distortion due to probe motion, and dispersion and polarization matching which are required when various probes are used. Experiments of path length compensation and vibration are conducted and the results demonstrate that this path length compensation method is feasible and the system can avoid environmental turbulences. Mirror and infrared card are imaged to demonstrate the performance of the proposed OCT system. This imaging approach is thus very suitable for endoscopic imaging, and the detailed method of expanding the OCT system for endoscopic OCT imaging is also presented..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 955 (2008)
Nonlinear Optics
Influence of Linear Focusing and Defocusing Effects on Interaction between Spatial Solitons
Zhong Weiping, and Yi Lin
Considering one-dimensional self-focusing inhomogeneous nonlinear media, we give out the intervals between spatial solitons using the conservation laws of nonlinear Schrdinger equation (NLS). The linear focusing effect and linear defocusing effect on the interaction between spatial solitons have been studied by numeriConsidering one-dimensional self-focusing inhomogeneous nonlinear media, we give out the intervals between spatial solitons using the conservation laws of nonlinear Schrdinger equation (NLS). The linear focusing effect and linear defocusing effect on the interaction between spatial solitons have been studied by numerical simulation. The results show that the interaction between spatial solitons increases when the linear focusing effect is considered and the interaction between spatial solitons decreases when the linear defocusing effect is considered. Solitons collide periodically when the self-focusing inhomogeneous nonlinear effect is neglected. The interval between solitons changes periodically with propagation distance when the linear defocusing effect is considered, but the collision between solitons does not occur. Solitons collide each other periodically when the linear focusing effect is considered and the interval increases because the loss can be suppressed by the linear focusing effect..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 960 (2008)
(1+1)-Dimensional Higher-Order Mode Breathers in Strongly Nonlocal Nonlinear Media
Zhao Xin, Chu Cunkun, Zhang Dongsheng, and Ma Fangfang
Based on the Snyder-Mitchell model, with the method of separation of variables, exact analytical Hermite-Gaussian (HG) solutions are obtained in strongly nonlocal nonlinear media. The comparison of analytical solutions with numerical simulations of the nonlocal nonlinear Schrdinger equation (NNLSE) shows that the analBased on the Snyder-Mitchell model, with the method of separation of variables, exact analytical Hermite-Gaussian (HG) solutions are obtained in strongly nonlocal nonlinear media. The comparison of analytical solutions with numerical simulations of the nonlocal nonlinear Schrdinger equation (NNLSE) shows that the analytical HG solutions are in good agreement with the numerical simulations in the case of strong nonlocality. The evolution of the HG beam in strongly nonlocal nonlinear media is discussed. The results demonstrate that the width of the HG breathers vibrates periodically as they travel. Furthermore, the critical power for the soliton propagation, the solution of HG solitons, and the propagation constant are obtained. The critical power does not change with the mode number, and the propagation constant increases as the mode number increases. Gaussian breathers and Gaussian solitons can be treated as special cases of HG breathers and HG solitons..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 965 (2008)
Optical Design and Fabrication
Optical Design for Unsymmetrical Aspherical Cubic Phase Plate Testing System
Xu Yingchao, Zhang Xin, and Zhou Ping
As one of the most promising methods in all the interferometric null tests, computer-generated holograms (CGH) can also be used in unsymmetrical aspherical surfaces testing. Taking the cubic surface as an example, the principle of testing unsymmetrical aspherical surfaces with CGH is given. The expression of the aberraAs one of the most promising methods in all the interferometric null tests, computer-generated holograms (CGH) can also be used in unsymmetrical aspherical surfaces testing. Taking the cubic surface as an example, the principle of testing unsymmetrical aspherical surfaces with CGH is given. The expression of the aberration for the cubic phase during propagation is deduced, and the results of the optical design for the cubic surface test system are listed. The separation of diffraction orders and the binary process of the continuous CGH phase function are discussed in detail, and the sample of the amplitude CGH is given. The minimum line spacing of the CGH is 40 μm and its effect on wavefront error is only 0.005λ. The tolerance analysis of testing system is done in detail, and the total effect from all alignment tolerances that affect testing system is 83.954 nm (root-mean-square)..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 971 (2008)
Lens Design Based on Ghost Image and Aberration Analysis in High-Power Laser Facility
Liu Hongjie, Liu Lanqin, Su Jingqin, Hu Dongxia, Zhou Wei, Zhao Junpu, Wang Wenyi, Mo Lei, Jiang Xinying, Jiang Xuejun, Zhang Kun, Zhu Qihua, Yu Haiwu, and Jing Feng
By the method of matrix optics, the formation process of ghost images from the residual reflection when beam passes through a single lens is analyzed and the relation between the localities of the ghost images and the curvature radius of the lens is achieved. From the relation, the localities of the ghost images can beBy the method of matrix optics, the formation process of ghost images from the residual reflection when beam passes through a single lens is analyzed and the relation between the localities of the ghost images and the curvature radius of the lens is achieved. From the relation, the localities of the ghost images can be determined by designing the curvature radius of the lens. The ghost images analysis is simplified considering the distribution characteristics of the beam path in high-power laser facility, based on which the distribution of the ghost images in the main amplification section is analyzed by the special software. By changing the curvature radius or tilting the lens, with the principles of avoiding the ghost images and minimizing the aberration, the curvature radius of the lens used in the main amplification section is selected as 1∶3 with a shape of crescent and convexity in the direction of more concentrated optics. The method proposed can also be applied to the lens design in high-flux complicated optics system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 976 (2008)
Spherochromatism of Hybrid Diffractive-Refractive Apochromatic Telescope Objectives
Leng Jiakai, Cui Qingfeng, Pei Xuedan, and Dong Hui
A positive lens, a negative lens and a diffractive optical element (DOE) can compose two kinds of hybrid diffractive-refractive telescope objectives when assembled differently. There is a different spherochromatism after the two systems correct secondary spectrum, spherical aberration and comatic aberration. Reasons ofA positive lens, a negative lens and a diffractive optical element (DOE) can compose two kinds of hybrid diffractive-refractive telescope objectives when assembled differently. There is a different spherochromatism after the two systems correct secondary spectrum, spherical aberration and comatic aberration. Reasons of the different spherochromatism of the two configurations are researched by Seidel aberration analysis. And spherochromatism of the configuration with diffractive optical element placed on the negative lens is 7 times as much as that of the other. When the substrate of diffractive optical element is the negative lens, a solution is presented to decrease spherochromatism of the system, and the value of spherochromatism is decreased to 0.307 mm. A conventional apochromatic optical system is designed in addition, and compared with the hybrid diffractive-refractive apochromatic optical system. It shows DOE can substitute special optical material of conventional optical system and obtain the same imaging effect. The influence of diffraction efficiency on the imaging optical system by the polychromatic integrated efficiency of DOE is analyzed at last..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 981 (2008)
Quantum Optics
Photon-Added Circular States and Their Propertities
Zhang Kefu, and Wang Zhongjie
The photon-added circular states are introduced by repeated application of Bose inverse operators on the circular states. Its non-classical properties are discussed, the Wigner function are derived. It is shown that the mean photon number is alternant changes between increase and decrease after photon adding in differeThe photon-added circular states are introduced by repeated application of Bose inverse operators on the circular states. Its non-classical properties are discussed, the Wigner function are derived. It is shown that the mean photon number is alternant changes between increase and decrease after photon adding in different strength regimes of the optical fields. Photon inverse operator can enhance sub-Poissonian distribution and suppress squeezing effects. It is also found that the quantum interference effects can be enhanced with the increases of photon-adding number and strength of light. For the different number of superposition,the same characteristics of the Wigner function can be obtained by choosing the suitable parameters..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 992 (2008)
Remote Sensing and Sensors
Synthetic Aperture Laser Imaging Radar (I): Defocused and Phase-Biased Telescope for Reception Antenna
Liu Liren
The diffraction from a target for a synthetic-aperture laser imaging radar is distinguished into three domains, and the methods of defocusing of telescope and spatial phase modulation by an additional plate are suggested to compensate the wavefront aberration of echo. In the Fresnel diffraction region the quadratic abeThe diffraction from a target for a synthetic-aperture laser imaging radar is distinguished into three domains, and the methods of defocusing of telescope and spatial phase modulation by an additional plate are suggested to compensate the wavefront aberration of echo. In the Fresnel diffraction region the quadratic aberration of echo can be eliminated by the defocused or phase-biased telescope and a phase history for aperture synthesis is correspondingly generated, and in the Fraunhofer region the quadratic wavefront can be also eliminated by the defocusing or phase-biasing but no phase history. Nevertheless, in the Rayleigh-Sommerfeld diffraction the higher-order aberrations cannot be compensated..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 997 (2008)
Thin Films
Design of Narrowband High-Reflection Filter Coating with Wide Stop Band
Peng Donggong, Wu Yonggang, Jiao Hongfei, Cao Hong, Wang Zhenhua, Fu Lianxiao, and Zheng Xiuping
Narrowband high-reflection filter coatings are very important in optical communication and optical detectors. A kind of narrowband high-reflection filter coating with structure of “substrate H(LH)m1αL(HL)m2βCrM air” was proposed, the influences of Cr thickness and two different matching film stacks on the characteristiNarrowband high-reflection filter coatings are very important in optical communication and optical detectors. A kind of narrowband high-reflection filter coating with structure of “substrate H(LH)m1αL(HL)m2βCrM air” was proposed, the influences of Cr thickness and two different matching film stacks on the characteristics of the filter coating was discussed, and the distribution of the internal electric field was calculated. Results show that a wider stop band in reflection can be realized with a thicker metallic layer and inserting a matching stack will produce a deep rejection of the stop-band. The matching stack leading to a greater admittance helps obtain a wide stop-band and narrow-band high reflection, and also produces zero electric field intensity in the Cr layer at the central wavelength, which consequently reduces the absorption and enhances the reflectance of the filter..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 1001 (2008)
Influence of Deposition Temperature on Residual Stress of Yttria-Stabilized Zirconia Thin Films
Xiao Qiling, He Hongbo, Shao Shuying, Shao Jianda, and Fan Zhengxiu
Yttria-stabilized zirconia (YSZ) films have been prepared by electron beam evaporation at different deposition temperatures with the starting material made of 12% (mole fraction) Y2O3 (99.99%) mixed with ZrO2 (99.99%) powder. The residual stress in yttrial-stabilized zirconia films was measured ZYGO Mark Ⅲ-GPI digital Yttria-stabilized zirconia (YSZ) films have been prepared by electron beam evaporation at different deposition temperatures with the starting material made of 12% (mole fraction) Y2O3 (99.99%) mixed with ZrO2 (99.99%) powder. The residual stress in yttrial-stabilized zirconia films was measured ZYGO Mark Ⅲ-GPI digital wavefront interferometer. The influence of deposition temperatures on residual stress was studied. The results show that residual stress in yttrial-stabilized zirconia films changes from tensile to compressive with the increase of deposition temperature and the value of the compressive stress increases with the increases of deposition temperature. At the same time, the microstructure of the yttrial-stabilized zirconia films was characterized by X-ray diffractometer. The relationship between residual stress and the microstructure was discussed. Also the residual stress was compared with that in pure ZrO2 films..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 1007 (2008)
Ultrafast Optics
THz Electromagnetic Radiation Based on the Stimulated Raman Scattering of Polariton
Zhang Xianbin, and Shi Wei
By using MgO∶LiNbO3 and undoped LiNbO3 crystals of 65 mm length, terahertz (THz) wave with the bandwidth of 0.34～2.90 THz is generated by using 1064 nm Q-switched Nd∶YAG laser with the energy of 12 mJ/pulse. Analysis shows that the polariton is an elementary excitation coupled from the electromagnetic TO phonon and incBy using MgO∶LiNbO3 and undoped LiNbO3 crystals of 65 mm length, terahertz (THz) wave with the bandwidth of 0.34～2.90 THz is generated by using 1064 nm Q-switched Nd∶YAG laser with the energy of 12 mJ/pulse. Analysis shows that the polariton is an elementary excitation coupled from the electromagnetic TO phonon and incident photon. In the LiNbO3 crystal, the radiation frequency of polariton, which has the electromagnetic properties, can partly cover THz range, and the stimulated Roman scattering for the polariton can generate THz wave. Furthermore, the radiation theory of polariton shows the dispersion characteristic of the polariton can determine the possibility of the crystal generating the THz wave, as well as its bandwidth range..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 1012 (2008)
Femtosecond Laser Pulses Induced Nanostructures on ZnO in Different Ablation Conditions
Guo Xiaodong, Li Ruxin, Yu Bingkun, and Ma Hongliang
Ablation conditions play an important role in the femtosecond laser pulses induced nanostructures on ZnO. When 800 nm, 150 fs, 250 kHz femtosecond laser pulses were focused on the surface of ZnO in air, distilled water and ethanol, different nanostructures were produced. Experimental results show that femtosecond laserAblation conditions play an important role in the femtosecond laser pulses induced nanostructures on ZnO. When 800 nm, 150 fs, 250 kHz femtosecond laser pulses were focused on the surface of ZnO in air, distilled water and ethanol, different nanostructures were produced. Experimental results show that femtosecond laser pulses induce nanowires with period of 180 nm in air, nanoballs constituted by ZnO nanowires are formed in distilled water, and obvious bifurcations are found in the nanostructures induced in ethanol. The results of Raman spectra indicate that the intensity of the fingerprint peak at 437 cm-1 declines after the irradiation, and the peak at 570 cm-1 is enhanced greatly. Surface nano-structuring evaluations and physical mechanisms under different conditions are analyzed in detail..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 28, Issue 5, 1017 (2008)
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