Contents
2013
Volume: 33 Issue 5
48 Article(s)
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Atmospheric Optics and Oceanic Optics
[in Chinese]
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Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 501001 (2013)
Diffraction and Gratings
Exposure Developing Simulation Study of Single-Mode-Resonance Interference Lithography
Yang Zheng, Zhang Zhiyou, Li Shuhong, Gao Fuhua, and Du Jinglei
A lithography method based on the single-mode-resonance (SMR) interference in the resist by employing the cylinder grating (CG) coupled structure is proposed. The CG coupled structure is used as a mask, and then the dielectric waveguide can be formed by combining CG with resist layer and substrate. Interference patternA lithography method based on the single-mode-resonance (SMR) interference in the resist by employing the cylinder grating (CG) coupled structure is proposed. The CG coupled structure is used as a mask, and then the dielectric waveguide can be formed by combining CG with resist layer and substrate. Interference pattern will be generated in the resist using the specific diffraction order (±1) from the CG diffraction. The resist layer plays the role of waveguide which can enhance the light field intensity 25～50 times stronger and greatly improve the light energy utilization ratio. Through simulation, the nanostructure with period smaller than λ/3 and groove width ranging of 42~88 nm (λ/10～λ/5) can be obtained with incident light wavelength of 441 nm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 505001 (2013)
Fiber Optics and Optical Communications
Research on the Polar Blind Zone of the Fiber Squeezer Polarization Controller
Zhang Qiye, Zhu Yong, Su Yang, Zhou Hua, and Jing Jisong
Polarization controller (PC) is an important device for the automatic polarization control algorithm, which is also an important part in the quantum key distribution system. A new method of analyzing the polar blind zone of the fiber squeezer polarization controller is presented based on the relation between the phase Polarization controller (PC) is an important device for the automatic polarization control algorithm, which is also an important part in the quantum key distribution system. A new method of analyzing the polar blind zone of the fiber squeezer polarization controller is presented based on the relation between the phase of the fiber squeezer and the rotation axis of the polarization state trajectory. The control principle is analyzed theoretically, and the interaction law between the changed phase and the rotation axis of the state of polarization′s trajectory is deduced. Based on the above results, the “polar blind zone” phenomenon of the two fiber squeezers cascade polarization controller is further expounded, namely only in the extremely individual input polarization state, arbitrary polarization states can be output. The vast majority of the input polarization states cannot arrive certain areas in the Poincare sphere. The accuracy of theoretical analysis is verified through comparing simulation results and experimental results. An idea of the polarization control algorithm based on avoiding blind area is proposed, which can reduce variable degrees of freedom..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 506001 (2013)
Adaptive Blind Equalization Using Electrical Recurrent Neural Networks
Ruan Xiukai, Li Chang, Tan Yanhua, and Zhang Yaoju
To solve the special issue of electrical adaptive blind equalization for wireless spatial diversity optical coherent receivers, a novel electrical adaptive blind equalization method based on dynamically driven recurrent neural networks (DDRNNs) with in-phase/quadrature amplitude component continuous activation is propoTo solve the special issue of electrical adaptive blind equalization for wireless spatial diversity optical coherent receivers, a novel electrical adaptive blind equalization method based on dynamically driven recurrent neural networks (DDRNNs) with in-phase/quadrature amplitude component continuous activation is proposed. A multi-threshold continuous amplitude sinusoidal type activation function is designed. This activation function is simple and flexible. How to select the parameters of the activation function is analyzed in detail and the new concepts of the approach point and leaving point are proposed. Amplification factor selection range of blind equalization is analyzed using DDRNN about electrical adaptive blind equalization from the perspective of activation function. Then, the applicability of detecting low-order quadrature amplitude modulation (QAM) signals using higher order QAM activation function is discoursed. Furthermore, the new energy function with the condition of the multi-threshold continuous activation function is proposed and proven. The design and analysis of the activation function and energy function are not only suitable for the blind equalization issues, but also can be extended to other fields..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 506002 (2013)
Experimental Research of High Gain and Low Noise Figure Optical Amplifier Based on Erbium-Doped Fiber
Zhang Kewei, Zhao Wei, Xie Xiaoping, Wang Wei, Qian Fengchen, and Han Biao
Considering the trade-off between the high gain and low noise figure in optical amplifier, a two-stage amplifier which has the structure to suppress the forward and backward-travelling amplified spontaneous emission noise with high gain and low noise figure based on Erbium-doped fiber is set up. Interpolation is used tConsidering the trade-off between the high gain and low noise figure in optical amplifier, a two-stage amplifier which has the structure to suppress the forward and backward-travelling amplified spontaneous emission noise with high gain and low noise figure based on Erbium-doped fiber is set up. Interpolation is used to test the power of amplified spontaneous emission (ASE) noise accurately. The gain and noise figures and some other parameters of the amplifier are analyzed. Comparison between the erbium-doped fiber amplifer (EDFA) and the commercial low noise EDFA is carried out. The results show that the highest gain of the EDFA in the experiment is 40.1 dB and the noise figure is 3.8 dB which is 0.8 dB above quantum-limit. The results when testing the amplifier and commercial EDFA in the same input power and gain show that the noise figure of the amplifier is 0.3 dB lower than the commercial EDFA..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 506003 (2013)
Digital Envelope Detection Technique for Brillouin Optical Time-Domain Reflectometry Based on Generalized Harmonic Wavelet Transform
Yang Wei, and Yang Yuanhong
The signal characteristics of the coherent heterodyne Brillouin optical time-domain reflectometry (BOTDR), as well as the impacts of the signal envelope on the spatial resolution and Brillouin frequency shift (BFS) measurement accuracy of the BOTDR are analyzed, respectively. A general algorithm model for the digital eThe signal characteristics of the coherent heterodyne Brillouin optical time-domain reflectometry (BOTDR), as well as the impacts of the signal envelope on the spatial resolution and Brillouin frequency shift (BFS) measurement accuracy of the BOTDR are analyzed, respectively. A general algorithm model for the digital envelope detection of an amplitude-modulated (AM) signal and the features of an ideal digital envelope detection algorithm are summarized, respectively. According to the zero phase shift ideal bandpass filtering features and passband designing flexibility of the generalized harmonic wavelet (GHW), a digital BOTDR envelope detection technique based on the generalized harmonic wavelet transform (GHWT) is proposed, and the envelope demodulation scheme is designed. The parameters optimization and experiments are made. The results show that, compared with the existing techniques, an undistorted signal envelope with a higher signal-to-noise ratio can be obtained by the proposed method, resulting in an undegraded spatial resolution and a higher BFS measurement accuracy for the BOTDR system. The experimental results are also analyzed according to the frequency domain characteristics of the algorithms..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 506004 (2013)
Design and Realization of a Radio-over-Fiber System Based on Self-Homodyned 60 GHz Receiver
Shen Da, Hu Zongfu, Wu Jiaqing, and Du Tianyu
A radio-over-fiber (RoF) system based on self-homodyned 60 GHz receiver is proposed and theoretically demonstrated. It overcomes the phase noise induced by incoherent lasers and avoids using wide bandwidth electro-optic devices and phase-locked loops. It not only supports the transmission of high bit-rate signals, but A radio-over-fiber (RoF) system based on self-homodyned 60 GHz receiver is proposed and theoretically demonstrated. It overcomes the phase noise induced by incoherent lasers and avoids using wide bandwidth electro-optic devices and phase-locked loops. It not only supports the transmission of high bit-rate signals, but also simplifies the central station and the remote antenna unit. The usage of baseband signals or intermediate frequency (IF) signals in the uplink and downlink improves the spectral utilization rate. The downlink uses the high-speed photo-detector to generate photonic 60 GHz millimeter wave, and the terminal uses self-homodyned receiver to remove the impact of phase noise and obtains baseband signal directly. The uplink uses the low-speed photo-detector to generate baseband signal directly, to decrease the price of the central station, and to reduce the number of optical sources. Using OptiSystem and Matlab simulation, it can be concluded that when the bit error rate (BER) of the uplink and downlink equals 10-9, the sensitivities of light can be improved by 7.1 dB and 1.5 dB, respectively. The proposed system realizes a 2.5 Gb/s baseband signal transmitting over a 32.4 km single mode fiber (SMF) link without error..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 506005 (2013)
Chaos Generation of Variable Parameters and Secure Communication Based on Optoelectronic Feedback Oscillation
Hu Hanping, Su Wei, Yu Zhiliang, and Liu Lingfeng
A new chaotic system and secure communication method are proposed based on optoelectronic feedback device with variable parameters, because the present system is easily attacked by the method of parameter estimation so as to affect the security of the communication. Dynamical changes of the gain coefficient of the secoA new chaotic system and secure communication method are proposed based on optoelectronic feedback device with variable parameters, because the present system is easily attacked by the method of parameter estimation so as to affect the security of the communication. Dynamical changes of the gain coefficient of the second-class system are generated by changing the injected light intensity through the output of the first-class system, which increases the number of controllable parameters in the system. The chaotic dynamics of the system are theoretically and numerically analyzed. The communication situation of the system in the chaotic modulation conditions and the chaos synchronization when the parameters including gain coefficient and time delay are not compatible is analyzed. The experimental results show that this scheme can increase the chaotic complexity, and can achieve the chaotic secure communication..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 506006 (2013)
Geometric Optics
Influence of Concentrated Illumination Parameters on the Output Characteristics of Back Contact Solar Cell Array
Cai Weiping, Li Ming, Ji Xu, Luo Xi, Xu Chengmu, Gao Guodong, and Ling Deli
This work investigates the influence of the concentrated illumination characteristics on the electrical output performance of photovoltaic/thermal system under trough concentrated sunlight. By measuring the illumination distribution at the focal plane for different distances and different opening widths of mirror with This work investigates the influence of the concentrated illumination characteristics on the electrical output performance of photovoltaic/thermal system under trough concentrated sunlight. By measuring the illumination distribution at the focal plane for different distances and different opening widths of mirror with the CCD camera, the illumination value distribution matrix is acquired, from which illumination parameters such as average illumination value, nonuniformity, peak deviation degree and illumination utilization ratio are extracted. The double exponential equivalent circuit model of the concentrator solar cell array is acquired by introducing recombination mechanism and parasitic resistance of the cell under the concentrated sunlight, and the simulation results agree well with the experimental records. The results show that the short circuit current and the relative maximum power increase with the increase of the relative average illumination value, and the degree of increase becomes smaller due to the intensifying of the recombination mechanisms and the increase of the ohmic losses for parasitic resistance, respectively. The open circuit voltage decreases with the increase of the non-uniform illumination degree and the peak deviation degree. The relative average illumination value has a greatest influence on the fill factor because of the ohmic losses for parasitic resistance. The conversion efficiency of solar cell depends on the illumination utilization ratio and the relative average illumination value. Taking series array of 6 pieces of 2 cm×2 cm back contact cells as an example, it can be concluded that, when the opening width of mirror is 157 cm and the distance from focal plane is 2 cm, the illumination distribution is the most suitable for the performance output of the back contact solar cell array..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 508001 (2013)
Generation of Long-Distance Quasi-Non-Diffracting Beams Using a Concave Axicon
Fang Xiang, Chen Jing, Wu Fengtie, Cheng Zhiming, and Zhu Jianqiang
A new type of axicon is proposed for generating quasi long-distance non-diffracting beams. This new type of optical element is grinded to a concave spherical surface on the bottom of a traditional axicon. The formation of the long-distance non-diffracting beams is analyzed by the theory of geometrical optics. Its ampliA new type of axicon is proposed for generating quasi long-distance non-diffracting beams. This new type of optical element is grinded to a concave spherical surface on the bottom of a traditional axicon. The formation of the long-distance non-diffracting beams is analyzed by the theory of geometrical optics. Its amplitude transmissivity function is derived. The intensity distribution of plane wave pass through the concave axicon is simulated by diffraction theory. The results show that the appropriate radius of curvature of axicon can produce long-distance non-diffracting beams with low divergent and good uniformity. Take an axicon with base angle γ of 10°, refraction index n of 1.51509 and curvature radius R of 75 mm for example, the maximum non-diffracting distance Zmax of 471.220 mm is obtained when radius of the incident beam a is 10 mm, while the traditional axicon with the same base angle and refraction index can obtain non-diffracting distance of 111.235 mm. The non-diffracting distance increases by 359.985 mm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 508002 (2013)
Holography
Spatial Angular Multiplexing for Enlarging Detection Area of Off-Axis Digital Holography with Low-Coherence-Length Light Source
Ma Zhonghong, Yang Yong, Wu Yongli, Deng Lijun, Ge Qi, and Zhai Hongchen
In the off-axis digital holography for detecting the ultra-fast phenomenon or obtaining the optical tomography information, the interference fringes are formed in a limited region due to the low coherence length of the light source, resulting in a corresponding decrease of the detected area of the object wavefront. A nIn the off-axis digital holography for detecting the ultra-fast phenomenon or obtaining the optical tomography information, the interference fringes are formed in a limited region due to the low coherence length of the light source, resulting in a corresponding decrease of the detected area of the object wavefront. A new recording method based on spatial angular multiplexing for enlarging the detected area in the above situation is proposed, in which multiple interferences between the object and the reference waves are simultaneously carried out by the spatial angular multiplexing. An image plane pulsed digital holographic system with two references based on spatial angular multiplexing is set up in the experimental system. The full-field reconstruction image can be obtained by fusing the two separately reconstructed parts of the images into a complete one. The experimental results demonstrate the validity of this method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 509001 (2013)
Imaging Systems
Active Surface-Profile Correction of 620 mm Thin-Mirror Based on Flotation Support
Li Hongzhuang, Zhang Zhenduo, Wang Jianli, Liu Xinyue, Wu Xiaoxia, Zhang Limin, Zhang Bin, and Wang Liang
For a meniscus mirror with 620 mm diameter and 18 mm thickness, active correction of surface-profile error is carried out. Through flotation support, the spatial position of the mirror is fixed. The support system of the mirror consists of 36 axial active supports and 6 lateral passive supports. Three points in the midFor a meniscus mirror with 620 mm diameter and 18 mm thickness, active correction of surface-profile error is carried out. Through flotation support, the spatial position of the mirror is fixed. The support system of the mirror consists of 36 axial active supports and 6 lateral passive supports. Three points in the middle circle of axial supports are chosen symmetrically as dummy hard points, and the flotation support is achieved through adjusting the support forces of other actuators to null the dummy hard point forces at all times. The Hartmann wavefront sensor is used as testing equipment and the least square method is used to calculate the active corrective forces. In the experiment, the correction ability of the active supports is analyzed first and low-frequency Zernike terms are selected for correction finally. Then the close-loop and open-loop correction at different elevations is carried out, and the results show that through flotation support, the surface-profile error can be corrected effectively without piston and tilt. More than 0.6λ (λ=632.8 nm) root-mean-square (RMS) of surface-profile error of the initial state can be corrected to λ/15 at any elevation angles, and the RMS of correction precision of open-loop reaches λ/10～λ/14. Through the experiment the feasibility of correction process with varying elevation angle and the arithmetic of correction forces are discussed, and the control of mirror position through flotation support is approved..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 511001 (2013)
Image Motion Velocity Field for Wide View Remote Sensing Camera and Detectors Exposure Integration Control
Wang Chong, You Zheng, Xing Fei, and Zhang Gaofei
For space-borne remote sensors with wide field of view, images on focal planes motion deform nonlinearly as well as vary with time due to the affects from satellites orbital motions, attitude maneuverings, jittering, earth ephemeris and geometrical characteristics, optical designs and so on. The distribution of image vFor space-borne remote sensors with wide field of view, images on focal planes motion deform nonlinearly as well as vary with time due to the affects from satellites orbital motions, attitude maneuverings, jittering, earth ephemeris and geometrical characteristics, optical designs and so on. The distribution of image velocity field determines the exposure integration accurate for the image formation procedure so as to affect the image qualities. A new method is proposed that it focus on to found the image motion velocity field mathematical model which especially appropriate to wide field of view sensors through analyzing the problems of image formation for apparent kinetic spatial object with smooth curved surface. Analytical formulas of image velocities are deduced. The algorithm is proved not only to be precise but also efficient. It can be employed as the dynamic imaging algorithms for embedded computers of orbiting payloads and their instrumentations. Based on this research, it′s concerned that an optimized approaches for charge coupled device (CCD) detectors exposure integration control via image velocities matching along with deflect angles compensations as the strong nonlinear image velocity fields..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 511002 (2013)
Stray Light Analysis and Suppression of Panoramic Annular Lens
Lu Tianxiong, Bai Jian, Huang Zhi, and Wang Kaiwei
When there is a highlight source in the field of a panoramic annular lens (PAL), the image will be covered by stray light like mist, so it is important to suppress stray light in a PAL system. The main sources of stray light in PAL are analyzed. As to the stray light caused by incomplete transmission of refractive surfWhen there is a highlight source in the field of a panoramic annular lens (PAL), the image will be covered by stray light like mist, so it is important to suppress stray light in a PAL system. The main sources of stray light in PAL are analyzed. As to the stray light caused by incomplete transmission of refractive surfaces, a suppression method is proposed, based on which a new PAL system is designed. In order to verify the feasibility of this method, a comparison of stray light performance is conducted between an ordinary PAL system and the new PAL system. The result indicates that in half field angle of 50°～85°, the stray light caused by incomplete transmission of refractive surfaces is reduced by 85% in the new PAL system, while the stray light doesn′t increase in other fields of view..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 511003 (2013)
Defocus Deblurring for Catadioptric Omnidirectional Imaging Based on Coded Aperture
Li Yongle, Wang Wei, Lou Jingtao, Liu Yu, Peng Yang, and Zhang Maojun
In catadioptric omnidirectional imaging systems, defocus blur is mainly caused by lens aperture and mirror curvature. The problem of image definition caused by defocus blur becomes more severe when high resolution sensors and large apertures are applied. One design of catadioptric omnidirectional imaging system for defIn catadioptric omnidirectional imaging systems, defocus blur is mainly caused by lens aperture and mirror curvature. The problem of image definition caused by defocus blur becomes more severe when high resolution sensors and large apertures are applied. One design of catadioptric omnidirectional imaging system for defocus deblurring, which is based on coded aperture, is proposed. The defocus blur of catadioptric omnidirectional imaging is analyzed in theory, and a method of obtaining optimal focused plane is proposed. With strategies of annuluses division and stitching of omnidirectional images, a deconvolution algorithm based on image sparse prior is used for the defocus blur omnidirectional image restoration to obtain all sharp omnidirectional images. The method is effective for catadioptric omnidirectional image defocus deblurring, which has an important meaning in improving catadioptric omnidirectional imaging quality and promoting applications in related fields..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 511004 (2013)
Instrumentation, Measurement and Metrology
Hyper Accuracy Star Location Algorithm Based on Nonsubsampled Contourlet Transform and Mapped Least Squares Support Vector Machine
Liu Nannan, Xu Shuyan, Hu Jun, Wang Dong, and Cao Xiaotao
In order to resolve the problem of light closed loop for the level of fine tracking system of survey camera high-precision image stabilization control, a star location method is proposed based on nonsubsampled contourlet transform (NSCT) and mapped least squares support vector machine (MLSSVM). Aiming at the characteriIn order to resolve the problem of light closed loop for the level of fine tracking system of survey camera high-precision image stabilization control, a star location method is proposed based on nonsubsampled contourlet transform (NSCT) and mapped least squares support vector machine (MLSSVM). Aiming at the characteristics of the star image, the image is denoised by adaptive NSCT. By analyzing the systematic errors of square centroid method in the frequency domain, its approximate analytic expression is obtained. By using Monte-Carlo numerical simulation method, regression analysis based on MLSSVM with radial basis function (RBF) kernel is proposed. The nonlinear function between the ideal star centroid location and the systematic errors is obtained, and is used to correct the systematic errors. Simulation results show that the proposed method is stronger in anti-noise performance and the star location accuracy is improved by 1 to 2 order of magnetude..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 512001 (2013)
Odd Aberration Measurement Technique Based on Peak Intensity Difference of Aerial Image
Tu Yuanying, Wang Xiangzhao, and Yan Guanyong
An odd aberration measurement technique based on peak intensity difference of aerial image is proposed for lithographic projection lens. By using the Hopkins theory of partially coherent imaging, the analytical expressions of the aerial image and the peak intensity difference are derived for the double-slit pattern. ThAn odd aberration measurement technique based on peak intensity difference of aerial image is proposed for lithographic projection lens. By using the Hopkins theory of partially coherent imaging, the analytical expressions of the aerial image and the peak intensity difference are derived for the double-slit pattern. This technique adopts a double-slit pattern as the measurement mark and the peak intensity difference of aerial image as the measurement parameter. Compared with the odd aberration measurement techniques based on image placement error (IPE), the technique based on the peak intensity difference can reduce the requirement for positioning accuracy of the aerial image, and accurate intensity measurement can improve the odd aberration measurement accuracy effectively. The odd aberration measurement accuracies under conventional illumination and dipole illumination are analyzed with PROLITH software. The simulation results show that the measurement accuracy can be further improved under dipole illumination. Taking coma Z7 as an example, the measurement accuracies are up to 0.29 nm and 0.19 nm under conventional illumination and dipole illumination, respectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 512002 (2013)
Comparison of Bidirectional Reflectance Distribution Function of Aluminum Alloy with Different Processing Technologies in Space Camera
Li Yongqiang, Guo Yongxiang, Liao Zhibo, Wang Jingyi, and Du Jianxiang
The definition of bidirectional reflectance distribution function (BRDF) and the principle of measurment apparatus are expounded. Aluminum alloy materials are widely used in space camera. The BRDF data of aluminum alloy samples dealt with different processing technologies are scaled by the compact BRDF measurement systThe definition of bidirectional reflectance distribution function (BRDF) and the principle of measurment apparatus are expounded. Aluminum alloy materials are widely used in space camera. The BRDF data of aluminum alloy samples dealt with different processing technologies are scaled by the compact BRDF measurement system. Every error source of compact BRDF measurement system is analyzed, and the methods to control and correct these errors are proposed. Comparison among BRDF data of aluminum alloy samples dealt with different processing technologies is significative for the conceptual design of space camera..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 512003 (2013)
Testing of Low Contrast Dynamic Target Acquisition Ability for Photoelectric Tracker
Huo Jinming, Shen Xiangheng, Ye Lu, Gu Yingying, and Zhang Ning
Currently, there are some problems on indoor test methods relating to low contrast dynamic target acquisition in photoelectric tracker, and related theory about low contrast dynamic target acquisition. Because low contrast dynamic target acquisition is one of the important factors relating to overall performance of phoCurrently, there are some problems on indoor test methods relating to low contrast dynamic target acquisition in photoelectric tracker, and related theory about low contrast dynamic target acquisition. Because low contrast dynamic target acquisition is one of the important factors relating to overall performance of photoelectric tracker, a new indoor method for performance assessment of low contrast dynamic target acquisition in photoelectric tracker is proposed. Infinite target source of adjustable contrast and turntable of adjustable speed are considered as detection device. Optical reference target, of which the contrast can be accurately measured, is provided for detecting opto-electronic tracker working in dynamic environments where the rotation rate can be precisely set, in order to validate acquisition ability of opto-electronic tracker for low contrast dynamic object based on target extraction. The opto-electronic tracker can also be evaluated in terms of acquisition performance or acquisition speed in different target contrasts and different movement speeds by the analyses of the target′s movement speed, target size that affects target contrast. The experimental results show that the photo-electronic tracker cannot effectively capture the object of which the diameter is 4 mm entering the field of view at the rate of greater than 7.45°/s from infinity in the background of which the spectral radiance is 38 W/(sr·m2). Furthermore, the results can be applied to evaluate the acquisition ability of photo-electric tracker by a given contrast dynamic target..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 512004 (2013)
Integrated Optics
Dispersion Characteristics of Ge20Sb15Se65 Chalcogenide Rib Waveguides
Liu Shan, Shen Xiang, Xu Tiefeng, Chen Yu, Chen Fen, Li Jun, Dai Shixun, and Nie Qiuhua
The model effective index for Ge20Sb15Se65 rib waveguides are calculated using the finite difference method. The group velocity dispersion properties of the quasi-TM single polarization of waveguides are systematically studied around the optical fiber communication wavelength (1550 nm), and their relationship with the The model effective index for Ge20Sb15Se65 rib waveguides are calculated using the finite difference method. The group velocity dispersion properties of the quasi-TM single polarization of waveguides are systematically studied around the optical fiber communication wavelength (1550 nm), and their relationship with the key structural parameters of the waveguide is also studied. Extensive simulation results show that the larger material dispersion can be reduced through the design of sub-micron waveguide structure. The rib width and height are controlled in the range of 500～900 nm and 400～1000 nm, respectively, zero dispersion or anomalous dispersion can be obtained by increasing the etched depth. In addition, the impact of rib width on dispersion is less obvious than that of rib height. The investigation results provide the basis of the size design and dispersion management for the chalcogenide optical waveguide applied to nonlinear all-optical devices. The results have some reference value to the design of chalcogenide glass optical waveguide devices used in all-optical signal processing..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 513001 (2013)
Lasers and Laser Optics
Pulse Stacking Scheme Based on Wavelength Division Multiplexing
Zeng Shuguang, Hu Jing, Wang Fei, and Liu Yan
For the case of pulse shaping by the usual pulse stacking scheme, the beat effect brings intensity fluctuation to the shaped pulse, and the spectrum interference effect will cause intensity fluctuation of the spectrum of the shaped pulse. To solve these problems, a pulse stacking scheme based on the wavelength divisionFor the case of pulse shaping by the usual pulse stacking scheme, the beat effect brings intensity fluctuation to the shaped pulse, and the spectrum interference effect will cause intensity fluctuation of the spectrum of the shaped pulse. To solve these problems, a pulse stacking scheme based on the wavelength division multiplexing (WDM) is proposed. Theoretical analysis and numerical simulation are developed on this scheme and this scheme is compared with the usual pulse stacking scheme. The results show that the pulse stacking scheme based on WDM can reduce the beat effect effectively, and smoother shaped pulse can be obtained. The larger the wavelength spacings are, the smoother shaped pulse we can get. Otherwise, this scheme can also reduce or eliminate the spectrum interference effect..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 514001 (2013)
Double-Longitudinal-Mode Continuous-Wave Laser with Ultra-Large Frequency Difference Used for Narrowband Terahertz-Wave Generation
Yang Qing, Huo Yujing, Duan Yusheng, and Zhang Yanyan
A double-longitudinal-mode NdYVO4 laser with ultra-large frequency difference is reported, which can be used for generating narrowband terahertz (THz) wave radiation. Continuous-wave (CW) double-longitudinal-mode operation of the laser is achieved based on the thin-disk laser medium and the micro-cavity, and the frequeA double-longitudinal-mode NdYVO4 laser with ultra-large frequency difference is reported, which can be used for generating narrowband terahertz (THz) wave radiation. Continuous-wave (CW) double-longitudinal-mode operation of the laser is achieved based on the thin-disk laser medium and the micro-cavity, and the frequency difference between the two longitudinal modes is in the THz band, tuned by adjusting the length of the laser cavity and varying within the range of 0.1~0.2 THz; The spectral linewidth of each longitudinal mode is as low as 20 MHz; The spatial distribution of the laser beam is a single transverse mode with the beam quality factor M2 of 1.292; The output power of the CW laser is 116 mW with the slope efficiency of 18.53% and the linear polarization degree of 0.993, when the power of the pumping light is 630 mW. Used as the seed light, the double-frequency output light of the double-longitudinal-mode laser will be amplified to obtain the high-power THz difference-frequency pumping light, which can realize the narrowband THz-wave radiation via collinear difference frequency generation in the nonlinear crystal, while the theoretical analysis indicates the spectral linewidth of the THz-wave expands to approximately 2 times than that of the THz difference-frequency pumping light, and using the THz difference-frequency pumping light with spot radius of 50 μm and peak power in kilowatt magnitude and 0.8 mm DAST crystal, the THz-wave radiation with output power in milliwatt magnitude can be generated..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 514002 (2013)
Research of Magnetic Effect in Little Non-Planar Resonators
Xu Guangming, Wang Fei, and Song Jianwen
Magnetic effects in the laser gyro application process can cause a change of the bias stability of gyro, which will have a major impact on gyro accuracy. The theoretical model about the magnetic effect of the laser gyro is established to analyze factors which generate the magnetic effect. Analyzing result shows that thMagnetic effects in the laser gyro application process can cause a change of the bias stability of gyro, which will have a major impact on gyro accuracy. The theoretical model about the magnetic effect of the laser gyro is established to analyze factors which generate the magnetic effect. Analyzing result shows that the little non-coplanar optical path in the laser gyro magnetic effects is the main reason of magnetic sensitivity. Magnetic effects of laser gyro can be decreased by adjusting the axial direction of a cavity pan mirror to reduce the optical path of non-coplanar angle. The above conclusions are proved by the experiment..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 514003 (2013)
Technology Research on High Power Slab Laser End-Pumped with Laser Diode Arrays
Li Mi, Hu Hao, Li Jianmin, Wu Yingchen, Lei Jun, Lü Wenqiang, Shi Yong, and Zhao Na
The experiment research and academic analysis on high power slab laser end-pumped with laser diode arrays (LDA) are developed, and the steady laser power output of the thin slab laser is achieved in resonator with 4f system. The continuous-wave laser with average power of 3.24 kW is achieved through plano-concave resonThe experiment research and academic analysis on high power slab laser end-pumped with laser diode arrays (LDA) are developed, and the steady laser power output of the thin slab laser is achieved in resonator with 4f system. The continuous-wave laser with average power of 3.24 kW is achieved through plano-concave resonator when the injecting power approaches to 10 kW. The loss coefficient of the laser resonator and the diffraction loss of the slab end are obtained indirectly by measuring the saturated gain coefficient of the laser medium when the laser output power is steady. The influence of the overlap factor on the laser power is analyzed, and the experimental results provide the basis for the optimization design to high power slab lasers..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 514004 (2013)
Machine Vision
Positioning Algorithm in Multi-Media Refractive Imaging System Based on Particle Swarm Optimization Calibration
Zhang Wenming, Wang Xin, Zhang Qiang, and Li Haibin
Due to the unacceptable errors and severe limitations when using high order radial distortion coefficients to compensate refraction in multi-media imaging system, we propose the multi-media positioning algorithm based on the calibration method using particle swarm optimization (PSO). The calibration toolbox in Matlab iDue to the unacceptable errors and severe limitations when using high order radial distortion coefficients to compensate refraction in multi-media imaging system, we propose the multi-media positioning algorithm based on the calibration method using particle swarm optimization (PSO). The calibration toolbox in Matlab is employed to calculate intrinsic and external parameters of the two cameras. The normal vector and the distance from optical center to refractive interface are calibrated by using PSO algorithm. A high-precision positioning algorithm is obtained using the method of light tracing. Experimental results show that the relative positioning errors are 0.70% and 0.45% in the proposed algorithm for uprightly and slantwise placed objects, respectively, while those are 1.71% and 8.96% in the method of high order distortion compensating refraction. Compared with the previous method, the proposed algorithm obviously decreases the influence of variation in depth of field on measurement precision and effectively improves the positioning accuracy..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 515001 (2013)
Illumination Assessment Method Based on Three-Dimensional Color Space for Automatic Visual Inspection
Xie Yu, Ye Yutang, Zhang Jing, and Liu Lin
Assessment and optimization of illumination are difficult issues in automatic visual inspection. After analyzing the images of visual inspection of printed circuit boards and their pixel value distribution in three-dimensional color space, an illumination assessment method is proposed. This merit function is based on qAssessment and optimization of illumination are difficult issues in automatic visual inspection. After analyzing the images of visual inspection of printed circuit boards and their pixel value distribution in three-dimensional color space, an illumination assessment method is proposed. This merit function is based on quantitative analysis of Euclidean distance of color in red-green-blue (RGB) space, fluctuation extent of pixel value and deviation of defect color. The experimental results show that this method is suitable for evaluating the illumination effect and complies with subjective feeling of human visual system. It is also shown that the precision is better than 1%. An illumination optimization experiment is performed and the optimum lighting effect is obtained based on the merit function. This method can be applied to other visual inspection areas, such as color print quality inspection and plastic product defects inspection..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 515002 (2013)
Optical Design and Fabrication
Development of Limb Imaging Spectrometer for Atmospheric Trace Gas Sounding
Xue Qingsheng, and Duan Minzheng
A prototype of ultraviolet (UV)/visible limb imaging spectrometer is designed and developed to satisfy the urgent requirements of space atmospheric remote sensing. The working waveband are 560～780 nm and 280～390 nm, using first order and second order diffraction of grating separately. The prototype is composed of an ofA prototype of ultraviolet (UV)/visible limb imaging spectrometer is designed and developed to satisfy the urgent requirements of space atmospheric remote sensing. The working waveband are 560～780 nm and 280～390 nm, using first order and second order diffraction of grating separately. The prototype is composed of an off-axis parabolic telescope and modified Czerny-Turner spectrometer. The root mean square(RMS) radius of the disc of confusion is less than 10 μm over the working waveband, and the image quality is obtained satisfactorily. The mass of prototype is 10 kg, the volume is 500 mm×350 mm×200 mm, the spatial resolution is 0.44 mrad, the spectral resolution is 1.52 nm, and all the requirements are satisfied. The field sounding experiment is implemented using the prototype of limb imaging spectrometer. The spectral data measured are compared with spectral data, which indicate that the prototype of limb imaging spectrometer has good function and performance, and satisfies the application requirements of sounding of atmospheric trace gas..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 522001 (2013)
Optical Design of the LED Illumination System with Adjustable View Angle
Xin Di, Liu Hua, Lu Zhenwu, and Wu Hongsheng
In order to satisfy the practical requirements that the view angle and the energy density distribution of the light beam should be adjustable in some specific lighting applications, an effective method to design LED illumination system with adjustable view angle is proposed. Considering the shortage of the traditional In order to satisfy the practical requirements that the view angle and the energy density distribution of the light beam should be adjustable in some specific lighting applications, an effective method to design LED illumination system with adjustable view angle is proposed. Considering the shortage of the traditional structure, a novel total internal reflection (TIR) lens is designed. The refractive surface is designed according to that the output light rays are parallel to the light axis. The TIR surface is designed according to that the total output light rays can realize the uniform illuminance on the remote target plane. A polycarb (PC) TIR lens with the view angle from 8° to 20° is designed as an example with this method. The simulation results show that, compared with the traditional structure, the average optical efficiency is increased by 13% and the average irradiance uniformity is increased by 17%. The volume of the novel TIR lens is decreased to about 1/5 of that of the traditional structure..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 522003 (2013)
Design of Optical System for a Novel Imaging Keratometer
Zheng Shaolin, Liu Yongji, Wang Zhaoqi, and Kong Xiangming
Compared with the traditional keratometer which adopts double image prism to measure the corneal refraction, a novel keratometer′s optical system, based on cursor imaging principle with impact structure and convenience in use, is proposed in this paper. The optical system includes imaging system and illumination systemCompared with the traditional keratometer which adopts double image prism to measure the corneal refraction, a novel keratometer′s optical system, based on cursor imaging principle with impact structure and convenience in use, is proposed in this paper. The optical system includes imaging system and illumination system. Imaging system, which consists of projection objective, cornea and photographic objective, adopts exterior focusing model. Illumination system adopts Kohler illumination, which realizes uniform illumination on the ring cursor, anterior corneal surface and the image plane on the CCD receptor. The image resolution can achieve 133 lp/mm, and the distortion is less than 1%. The measurement accuracy of corneal refraction reaches to 0.25 D (0.02 mm for curve radius), and the measurement range is 30~60 D (5.5~11 mm for curve radius). With high measurement accuracy and a wide range of measurement for the corneal refraction, the optical system simplifies the keratometer′s structure and operation for practitioners effectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 522004 (2013)
Development and Performance Testing of Optical System for Star Sensor
Li Jing, Yang Baoxi, Hu Zhonghua, Xiao Yanfen, and Huang Huijie
According to detection requirements of the star sensor system, a double Gauss optical system with image side telecentricity is designed. This optical system, not only satisfies the special requirements of dispersed spot and energy centralized distribution, but also possesses large aperture, low distortion, small color According to detection requirements of the star sensor system, a double Gauss optical system with image side telecentricity is designed. This optical system, not only satisfies the special requirements of dispersed spot and energy centralized distribution, but also possesses large aperture, low distortion, small color deviation, and insensitivity to defocus. The optical performance of the star sensor is quantitatively measured by modulation transfer function (MTF) analyzer. 80% energy of dispersion spot for each field of view is concentrated in a circle with 20 μm diameter. Meanwhile, a method using one-dimensional precision rotating platform and single star simulator to test the centroid distortion of optical system is proposed. The test results show that centroid distortion of the star point is better than 9 arc second..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 522005 (2013)
Design of Cooled Infrared Dual-Band Common Path Refractive-Diffractive Telephoto Objective
Zhang Yu, and Wang Wensheng
Aiming at the needs of remote infrared target detection, for improving the detection ability of optical system in a complex environment, the cooled common path infrared dual-band refractive-diffractive telephoto objective is designed. The working wave-band of the telephoto objective covers the infrared medium-wave (3~5Aiming at the needs of remote infrared target detection, for improving the detection ability of optical system in a complex environment, the cooled common path infrared dual-band refractive-diffractive telephoto objective is designed. The working wave-band of the telephoto objective covers the infrared medium-wave (3~5 μm) and infrared long-wave (8~12 μm). A transmission common path structure is used in this telephoto objective. The telephoto objective consists of objective and relay lens. The focal length of the telephoto objective is -200 mm, the F number is 2.8, and the full field of view is 3.2°. The detector adopted is HgCdTe mid-wave infrared focal plane array of 2/3 inch (1 inch=25.4 mm). Its resolution is 320 pixel×256 pixel and pixel size is 30 μm. The image quality of this telephoto objective is prefect. At cut-off frequency of 17 lp/mm, the modulation transfer function (MTF) of the infrared medium-wave is greater than 0.5 for each field of view, and the MTF of the infrared long-wave is greater than 0.3 for each field of view. The root mean square radius of spot diagram for the each field of view is much smaller than Airy disk radius. The cold shield efficiency is 100%. This infrared telephoto objective can be used in the observation-aiming system of the tank..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 522006 (2013)
Optical Devices
A Novel LED Photo-Electro-Thermal Model with Simplified Variables
Xu Yuzhen, and Lin Weiming
The existing photo-electro-thermal theory and models of LED are analyzed. Based on the model proposed by Hui et al., combining mathematical derivations, simulations and experiments, a linear relationship between the positive input current and input power is studied when the LED package module is at a constant temperatuThe existing photo-electro-thermal theory and models of LED are analyzed. Based on the model proposed by Hui et al., combining mathematical derivations, simulations and experiments, a linear relationship between the positive input current and input power is studied when the LED package module is at a constant temperature of heatsink. From the circuit control strategy, a novel photo-electro-thermal LED model with simplified variables is proposed. The temperature of heatsink and input current are the two variables of this model, which are easy to measure and control. The feasibility of the proposed model is verified by optical experiments on two typical LED package modules. Compared with the model proposed by Hui et al., the model is simple and convenient to perform circuit drive control. It is helpful for the design of the LED lighting system and the establishment of LED drive power control strategy with excellent optical properties, providing a theoretical basis for LED dimmer control technology..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 523001 (2013)
Optics at Surfaces
Extracting Phase Information of Surface Plasmon Resonance Imaging System
Wang Yijia, Zhang Chonglei, Wang Rong, Zhu Siwei, and Yuan Xiaocong
There is a request of high throughput measurement when surface plasmon resonance (SPR) biosensors are applied to real-time measure binding reaction of bio-molecular, so SPR biosensors need wide-field imaging ability. A differential interferometry SPR imaging biosensor based on Mach-Zehnder configuration which can decreThere is a request of high throughput measurement when surface plasmon resonance (SPR) biosensors are applied to real-time measure binding reaction of bio-molecular, so SPR biosensors need wide-field imaging ability. A differential interferometry SPR imaging biosensor based on Mach-Zehnder configuration which can decrease environment noise effectively is set up. An algorithm is created to extract phase information in differential phase-sensitive SPR imaging biosensor. After signal and reference beams are combined, p and s polarization beams are splitted by a Wollaston prism and received by CCD after focused by lens. A correlation algorithm is used to align these two light spots. The phase is extracted from several periods of p and s polarization interference intensity changes and the noises decreases simultaneously by the average. The differential phase is calculated by point to point subtraction. The differential phase image is obtained by scanning in this way. For phase information is extracted from time axis in the system, there isn't decrease exist in spatial resolution. The system detects one data per 10 s. Spatial resolution of the system is 31.25 μm×20.83 μm and refractive index resolution is 10-5RIU..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 524001 (2013)
Shape Optimization and Analysis of Sensing Properties of Localized Surface Plasmon Resonances for Triangle Metal Nanoparticles
Luo Tingjun, Wan Lingyu, Huang Jiqin, Pang Lin, and Zhang Weiping
Using three-dimensional (3D) finite-difference time-domain method, optical and sensing properties of local surface plasmon resonances of triangle metal nanoparticles with different geometric parameters are studied numerically. The influences of four parameters, including the height, the tip angle, the radius of curvatuUsing three-dimensional (3D) finite-difference time-domain method, optical and sensing properties of local surface plasmon resonances of triangle metal nanoparticles with different geometric parameters are studied numerically. The influences of four parameters, including the height, the tip angle, the radius of curvature of vertex angle of the triangle and the gap, on the extinction spectra, bulk refractive index sensitivities and figures of merit of single-triangle and bi-triangle gold nanostructures are analyzed in detail. An optimization method of sensing properties is given based on the results of numerical calculation. An optimization bi-triangle nanostructure with the bulk refractive index sensitivity of 941 nm/RIU and figure of merit of 6.8 is presented..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 524002 (2013)
Physical Optics
Expressions of Totally Polarized Light Employing Circular and Elliptical Basic Vectors and Methods of Locus Plotting of Optical Vectors
Wang Zhengping, and Yu Long
The expressions of totally polarized light with circular and elliptical basic vectors are two of the approaches to characterize states of optical polarization. Based on the theory of polarization optics and Jones calculus, we derive two sets of fundamental formulae expressing the states of optical polarization exploitiThe expressions of totally polarized light with circular and elliptical basic vectors are two of the approaches to characterize states of optical polarization. Based on the theory of polarization optics and Jones calculus, we derive two sets of fundamental formulae expressing the states of optical polarization exploiting circular and elliptical basic vectors, propose a way to describe simultaneously four physical parameters using two elements of an optical vector，and an approach of drawing complex optical vectors′s locuses. The first step of the approach is to turn the complex optical vector into the form of a sum of two row vectors, and then, to superpose the two ellipses drawn according to the two vectors, into the final ellipse. We assess the feasibility of the methods proposed here, exploiting some typical examples of states of optical polarization. The results show that the formulae derived here are correct and the methods proposed here are feasible..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 526001 (2013)
Optical Conductivity Spectrum in a Conventional Two-Dimensional Electron Gas and Graphene
Yang Cuihong, Wei Xiangfei, Luo Yuan, and Liu Liwei
Monolayer graphene is a two dimensional electron gas (2DEG) which is obtained at room temperature. The optical, electrical and magnetic transport properties (e.g., room temperature quantum Hall effect, high mobility, high thermal conductivity, minimum conductivity, etc.) in graphene represent different transport behaviMonolayer graphene is a two dimensional electron gas (2DEG) which is obtained at room temperature. The optical, electrical and magnetic transport properties (e.g., room temperature quantum Hall effect, high mobility, high thermal conductivity, minimum conductivity, etc.) in graphene represent different transport behaviors for the difference of it′s linear dispersion relation and that of traditional 2DEG. This graphene material has huge potential applications in microelectronics and transparent conductive films. The dielectric function under the random phase approximation (RPA) is employed to evaluate the optical conductivity in the traditional 2DEG and the graphene system. It is found that the main optical conductivity is induced by the inter-band transition with two-branch energy spectrum, while the contribution by the intra-band transition is very small. The shape of the conductivity spectrum depends on the Fermi energy and the broadening width which is determined by the scattering mechanism. When the optical energy is larger than 2EF, the optical conductivity tends to a constant which is consistent with the experimental result..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 526002 (2013)
Spin Angle Splitting in Spin Hall Effect of Light
Zhao Junqian, Zhou Xinxing, and Luo Hailu
Spin angle splitting phenomenon in spin Hall effect of light (SHEL) is studied theoretically. The quantitative relationships of incident angle, polarization state and beam transmission distance upon the spin angle splitting of SHEL are revealed, by establishing horizontal polarization and vertical polarization transmisSpin angle splitting phenomenon in spin Hall effect of light (SHEL) is studied theoretically. The quantitative relationships of incident angle, polarization state and beam transmission distance upon the spin angle splitting of SHEL are revealed, by establishing horizontal polarization and vertical polarization transmission models of beam total internal reflection at the interface from glass to air. It is found that only when the incident angle is bigger than the critical angle, will the spin angle splitting phenomenon appear, or will there be only space shift in SHEL. The angle shift decreases with the increase of the incident angle, it also changes with the increase of transmission distance at the same time. Transverse shift will reverse because of the influence of spin angle splitting in the case of vertical polarization light. The spin angle splitting phenomenon of SHEL can be explained by the aspect of phase difference between parallel and vertical components of Fresnel reflection coefficient. It is predicted that the similar spin angular splitting would also exist in the cases of loss media and layer nanostructures..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 526003 (2013)
Quantum Optics
Entanglement of an Atom Interacting with Glauber-Lachs State in Multiphoton Jaynes-Cummings Model
Feng Chuan, Sachuerfu, and Li Hongxing
The entanglement properties of an atom interacting with Glauber-Lachs state in multiphoton Jaynes-Cummings model are studied by means of full quantum theory. The influences of the mean number of coherent photons, the mean number of thermal photons, the number of transition photons and the atomic initial state on the enThe entanglement properties of an atom interacting with Glauber-Lachs state in multiphoton Jaynes-Cummings model are studied by means of full quantum theory. The influences of the mean number of coherent photons, the mean number of thermal photons, the number of transition photons and the atomic initial state on the entanglement properties of the system are discussed. Results indicate that the entanglement is a non-monotonic function of the mean number of coherent photons and the mean number of thermal photons. With the increasing of the number of transition photons, the oscillation frequency of the entanglement degree of the system increases obviously and the average entanglement degree of the system decreases. And the atomic initial state affects the entanglement degree of the system obviously. Although the mixedness degree of atomic initial state tend to the ground state and to the excited state are identical, the effects on average entanglement of the system are different. The higher the degree of initial mixedness of the atom is, the more obvious the influence on entanglement degree of the system by the number of transition photons will be..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 527001 (2013)
Remote Sensing and Sensors
Image Motion Compensation of Space Camera with Large Field of View Using Earth Ellipsoid
Wu Xingxing, Liu Jinguo, and Zhou Huaide
During the imaging process of space camera with large field of view, longitudes and latitudes of objects on earth corresponding to different field of view positions differ from each other. As a result magnitudes and directions of image motion speeds caused by rotation of the earth are different. As the earth is actuallDuring the imaging process of space camera with large field of view, longitudes and latitudes of objects on earth corresponding to different field of view positions differ from each other. As a result magnitudes and directions of image motion speeds caused by rotation of the earth are different. As the earth is actually an ellipsoid, distances between objects on earth and the projection center change along with field of view position and geocentric angle from ascending node to subastral point. Therefore image motion speed caused by orbital motion of the satellite varies. Formulas for calculation of image motion speed and drift angle at different field of view positions using earth ellipsoid are deduced based on analyzing imaging principle of space camera with large field of view. Influences of adjusting row transfer periods uniformly and separately and drift angles of a space camera with large field of view on imaging quality are analyzed. Results of experiments and analysis indicate that using no more than 5% reduction of modulation transfer function (MTF) as a constraint condition, row transfer periods can be adjusted uniformly if no more than 8 time delay intergration (TDI) stages are used. Otherwise row transfer period of each CCD chip should be adjusted individually. If 16 TDI stages are used, reduction rate of along-orbit MTF should be cut down from 17.33% to 0.53% as row transfer period of each CCD chip is adjusted individually..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 528001 (2013)
Cross-Calibration Method Based on Hyperspectral Imager Hyperion
Xu Wenbin, Zheng Xiaobing, and Yi Weining
A new cross-calibration method is proposed. In this method, hyperspectral imager Hyperion is used as reference sensor, Terra and MODIS are used as sensor to be calibrated, and Dunhuang site is selected as target, with matching elements including field, time, geometry and spectrum considered in the process of cross-caliA new cross-calibration method is proposed. In this method, hyperspectral imager Hyperion is used as reference sensor, Terra and MODIS are used as sensor to be calibrated, and Dunhuang site is selected as target, with matching elements including field, time, geometry and spectrum considered in the process of cross-calibration. At-sensor radiances of fourteen bands of MODIS are predicted, and the predicted values are then compared with the measured values of corresponding bands. The results show that the differences of thirteen bands are no more than 7.7%, and the difference of the ninth bands is 11.9%. The total uncertainties of cross-calibration are superior to 7.7%. The principle feasibility of the new method is validated..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 528002 (2013)
Hyperspectral Sensor in Flight Spectral Calibration Based on Characteristic Spectra of Atmosphere
Chen Hongyao, Zhang Liming, Li Xin, Si Xiaolong, Yang Baoyun, and Zhu Xuemei
Spectral calibration is the premise to realize quantitative of hyperspectral remote sensing. A spectral calibration method based on atmospheric absorption features is presented. The spectral calibration techinque first separate the reflectance caused by atmosphere and surrounding, which is indepedent of the character oSpectral calibration is the premise to realize quantitative of hyperspectral remote sensing. A spectral calibration method based on atmospheric absorption features is presented. The spectral calibration techinque first separate the reflectance caused by atmosphere and surrounding, which is indepedent of the character of the remote sensor, and then is executed by spectral to match between the equivalent spectral reflectance and the one after low-pass filter. Using the spectral calibration method, a domestic airborne hyperspectral sensor is calibrated in flight. The result shows that both the central wavelength and the bandwidth of the sensor change. The accuracy of the spectral calibration can be verified by checking the sharp protruding in the inversion spectral reflectance or by comparing measured and radiative transfer calculated spectral radiance in the oxygen 760 nm absorption peak profiles. Analysis shows that, the main influence factors of the spectral calibration uncertainty are data signal-to-noise and sensor radiometric calibration..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 528003 (2013)
Scattering
Study on Resonant Models in Two-Layer Micro-Sphere Cavity
Sun Xianming, Liu Wanqiang, Wang Haihua, and Lei Chengxin
Optical characteristics of the two-layer micro-sphere cavity are studied based on the method of separation of variables. The affection of the position and size of the inclusion and the incidence angle of the plane wave to the morphology-dependent resonance (MDR) position and profile is analyzed through the calculation Optical characteristics of the two-layer micro-sphere cavity are studied based on the method of separation of variables. The affection of the position and size of the inclusion and the incidence angle of the plane wave to the morphology-dependent resonance (MDR) position and profile is analyzed through the calculation of the scattering efficiency and asymmetry factors of the two-layer sphere. The results show that the position and size of the inclusion affect the MDR of eccentric sphere. Through the computation of the angle-averaged internal intensity, it is found that the MDR position and profile will be greatly affected by the incidence angles of plane wave when the inclusion is located near the position of concentrated intensity..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 529001 (2013)
Spectroscopy
Correction of Spatial Heterodyne Interferogram Base on Frequency Domain Analysis
Ye Song, Xiong Wei, Wang Xinqiang, Hong Jin, and Qiao Yanli
Spatial heterodyne spectroscopy (SHS) is a new spectroscopic technique which can achieve high spectral resolution. The basic concepts of spatial heterodyne spectrometer are described. The two-dimensional (2D) interference fringe distortion is due to asymmetry of double optical path, which caused by the errors from optiSpatial heterodyne spectroscopy (SHS) is a new spectroscopic technique which can achieve high spectral resolution. The basic concepts of spatial heterodyne spectrometer are described. The two-dimensional (2D) interference fringe distortion is due to asymmetry of double optical path, which caused by the errors from optical systems of the interferometer. According to the characteristics of SHS interference fringe distortions, a SHS interferogram correction method based on frequency domain analysis is presented. The corrected coordinate of fast Fourier transform (FFT) frequency domain signal obtained from monochromatic source calibration. Then the calibration curve fitting from corrected coordinate can be used for correction of SHS interferogram. Spectral experiments are operated on the SHS instrument by monochromatic source and Gaussian continuous spectrum source. The experimental results show that the correction method can effectively remove interference of system asymmetry, correct 2D SHS interferogram and improve spectral inversion accuracy of spatial heterodyne spectrometer..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 530001 (2013)
Theoretical and Experimental Researches on the Detection Phase Determination of Frequency Modulation Spectroscopy Based on the Residual Amplitude Modulation
Fu Xiaofang, Ma Weiguang, Tan Wei, Zhao Gang, Li Zhixin, Dong Lei, Zhang Lei, Yin Wangbao, and Jia Suotang
A method of determining the detection phase of frequency modulation spectroscopy based on the residual amplitude modulation is proposed. According to the theoretical analysis, when there is a residual amplitude modulation in the frequency modulation spectroscopy, the signal amplitude without absorption is proportional A method of determining the detection phase of frequency modulation spectroscopy based on the residual amplitude modulation is proposed. According to the theoretical analysis, when there is a residual amplitude modulation in the frequency modulation spectroscopy, the signal amplitude without absorption is proportional to the cosine of detection phase. Based on this result, the detection phase could be determined directly by experiment. In order to increase the measure accuracy, a low frequency voltage control is applied to the electro-optical modulator. Comparing with the detection phase given by fitting the lineshape of frequency modulation spectroscopy with absorption, the new measured detection phase shows a deviation of less than 0.04 rad (2°), which verifies the validity of the new detection method and raises the measure speed of detection phase..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 530002 (2013)
Eliminating Complex Background Noise of Raman Spectrum Based on Configuration Similarity Comparing Method
Xia Liangping, Li Huadong, Yin Shaoyun, Wu Yunfeng, Shi Haofei, and Du Chunlei
The effective information of Raman spectrum is easy to be weakened or even submerged by the background noises in complex environment. The configuration similarity comparing method (CSCM), which is based on the shape similarity of the information and the background spectrum, is proposed to eliminate the background noiseThe effective information of Raman spectrum is easy to be weakened or even submerged by the background noises in complex environment. The configuration similarity comparing method (CSCM), which is based on the shape similarity of the information and the background spectrum, is proposed to eliminate the background noises. Exampled as experimental data, the CSCM principle is analyzed and the processing steps are introduced. By comparing with other two traditional methods, the CSCM recovers more Raman information and the baseline is flat, which is advantageous in further data analysis..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 530003 (2013)
Thin Films
Prepared by Sol-Gel Method Magnesium Fluoride Anti-Reflective Films for Fluorophosphate Glass
Hu Wenjie, Jia Hongbao, Sun Jinghua, Ding Ruimin, Wu Dong, and Xu Yao
Stable MgF2 sols are synthesized by sol-gel method under nitrogen atmosphere at room temperature, with magnesium methoxide and hydrofluoric acid aqueous solution as reactants. Characterized by transmission electron microscopy, MgF2 sols are accumulated by irregular particles of about 10 nm diameter. The X-ray diffractiStable MgF2 sols are synthesized by sol-gel method under nitrogen atmosphere at room temperature, with magnesium methoxide and hydrofluoric acid aqueous solution as reactants. Characterized by transmission electron microscopy, MgF2 sols are accumulated by irregular particles of about 10 nm diameter. The X-ray diffraction results that xerogels and films all show tetragonal crystalline MgF2 and the average grain size is about 8.9 nm. With prepared MgF2 sols, MgF2 anti-reflective films are dip-coated on well-polished and well-cleared fluorophosphate glass substrates. Atomic force microscope images of films indicate that the surfaces of films are very smooth, and the root mean square roughness is as small as 1.6 nm. At 351 nm wavelength, the transmittance of fluorophosphate glass coated by anti-reflective film is 6.49% higher than that of the substrate. The laser damage thresholds of films and substrate are both higher than 35 J·cm-2, tested by 351 nm pulse laser (8 ns pulse width)..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 531001 (2013)
Ultrafast Optics
Polarization-Dependent Optical Guiding in Low Repetition Frequency Femtosecond Laser Photowritten Type II Fused Silica Waveguides
Li Dongjuan, Lin Ling, Lü Baida, and Cheng Guanghua
The dependences of self-assembled nanograting in fused silica on low repetition frequency femtosecond laser parameters and scanning parameters are investigated. The results show that the filling factor of nanograting for scanning path cross section depends on the writing parameters. The type II waveguide in fused silicThe dependences of self-assembled nanograting in fused silica on low repetition frequency femtosecond laser parameters and scanning parameters are investigated. The results show that the filling factor of nanograting for scanning path cross section depends on the writing parameters. The type II waveguide in fused silica can be written under some writing condition and shows polarization-dependent guiding properties. Similar polarization-dependent guiding properties with 100 kHz situation is proved in experiment by hexagonal structures assembled from type II traces. Ideal models of the cross-sectional refractive index profiles of type II waveguides and the hexagonal structures are constructed. Corresponding modes are simulated using the finite element analysis method. It is found that the polarization-dependent optical guiding properties of type II waveguides are due to polarization-dependent scattering of nanograting rather than form birefringence in theory and experiment..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 532001 (2013)
Double-Line-Density Grisms for Dispersion Compensation of Ultra-Short Laser Pulses
Xu Tingting, Sun Meizhi, Yang Qingwei, Wang Nannan, Guo Ailin, Kang Jun, Zhu Haidong, and Xie Xinglong
A new device for dispersion compensation of ultra-short laser pulses is developed. This setup is made up of a pair of double-line-density grisms. Each grism consists of a prism and a grating separated from each other. It is featured that the density of the second grating doubles the first one′s. The numerical results oA new device for dispersion compensation of ultra-short laser pulses is developed. This setup is made up of a pair of double-line-density grisms. Each grism consists of a prism and a grating separated from each other. It is featured that the density of the second grating doubles the first one′s. The numerical results of ray tracing show that this setup can compensate third-order dispersion independently without any spatial distortion, and the compensation sphere covers a wide scale from negative to positive. It provides a certain reference for dispersion compensation of femtosecond pulses in chirped pulse amplification systems..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 5, 532002 (2013)
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