Contents
2009
Volume: 29 Issue 5
56 Article(s)
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Atmospheric Optics and Oceanic Optics
A Method on the Decision of Resolution of Shack-Hartman Sensor According to Far-field Spot
Chen Hongli, and Rao Changhui
A method on how to decide the resolution of Shack-Hartmann sensor when it is used to measure an unknown incident wavefront is presented. The phase of incident wavefront can be according to Fourier progression, the complex amplitude of incident wavefront can be expanded according to Bessel progression, and then the distA method on how to decide the resolution of Shack-Hartmann sensor when it is used to measure an unknown incident wavefront is presented. The phase of incident wavefront can be according to Fourier progression, the complex amplitude of incident wavefront can be expanded according to Bessel progression, and then the distribution of intensity of far-field spot can be got through Fourier transform. The results indicate that the phase spectrum of incident wavefront have affiliation with the distribution of intensity of far-field spot. The resolution of Shack-Hartmann sensor can be decided through measuring the distribution of intensity of far-field spot. This method provides the theoretic support on the decision of the number of sub-aperture of Shack-Hartmann sensor. So the problem of the decrease in accuracy of Shack-Hartman sensor because of the lack of sub-apertures can be solved..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1137 (2009)
Performances Index and Convergence Speed of Parallel Gradient Descent Algorithm in Adaptive Optics of Point Source
Chen Bo, Yang Huizhen, Zhang Jinbao, Li Xinyang, and Jiang Wenhan
The stochastic parallel gradient descent (SPGD) algorithm can be used to correct phase distortion by optimizing the system performance index directly, so it is a promising control algorithm for adaptive optics (AO) system. In the point-source adaptive optics based on SPGD algorithm, the quadratic sum of intensity, the The stochastic parallel gradient descent (SPGD) algorithm can be used to correct phase distortion by optimizing the system performance index directly, so it is a promising control algorithm for adaptive optics (AO) system. In the point-source adaptive optics based on SPGD algorithm, the quadratic sum of intensity, the mean radius and encircled energy are usually used as the system performance index. The relation between the three performance index and the RMS value of aberrant wavefront are analyzed using numerical simulation. Then an adaptive optics experimental system is set up and the static phase-distortion correction experimental is carried out to research three performance index of SPGD algorithm. The experiment results show that the mean radius is the most efficient as the system performance index compared with the other two, which is accordant with the result of numerical simulation previously. The relation between the speed of convergence and control channel number is also researched. The experimental results show that the iteration amount required by convergence of performance index curve is increased remarkably when the control channel number is increased, and it is approximately proportional to square root of control channel number..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1143 (2009)
Phase Errors Compensation in Airborne Synthetic Aperture Ladar Data Processing
Hua Zhili, and Li Hongping
Accurately understanding the effects of phase fluctuation on the laser beam propagation through the atmospheric turbulence, and then making an effective wavefront correction will improve the imaging ability of practical synthetic aperture ladar systems. Based on the phase structure function of laser beam, the structureAccurately understanding the effects of phase fluctuation on the laser beam propagation through the atmospheric turbulence, and then making an effective wavefront correction will improve the imaging ability of practical synthetic aperture ladar systems. Based on the phase structure function of laser beam, the structure-function method for generating phase screens is presented, by which the Kolmogorov turbulence of different strength is numerically simulated to investigate its distortion on SAL imaging ability. By combining it with the rank one phase estimation (ROPE) algorithm, improvement of both accuracy and efficiency can be obtained by overcoming the weakness that ROPE is sensitive to initial value. Experiments show that the simulating results by structure function method, will be much closer to the theoretical value than that by spectrum method, and computational complexity will also be reduced from O(N2) to O(N). At the same time, image distortion induced by atmospheric turbulence within a certain intensity range can be restored by the modified ROPE algorithm. Compared with the traditional ROPE, compensation results by the modified method can have a 5 dB signal-to-noise ratio improvement, and computing time can be cut down by 30%..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1149 (2009)
The Influence of the Aspect Ratio to the Light Scattering Properties of Cylinder Ice Particles
Gong Chunwen, Wei Heli, Li Xuebin, Shao Shiyong, Xu Qingshan, and Chen Xiuhong
The influence of the aspect ratio to the light-scattering properties of small size cylinder ice particles in cirrus cloud is studied by T-matrix method. The light-scattering characteristic quantities such as the phase function, extinction efficiency, asymmetrical parameter and single-scattering albedo are computed.The The influence of the aspect ratio to the light-scattering properties of small size cylinder ice particles in cirrus cloud is studied by T-matrix method. The light-scattering characteristic quantities such as the phase function, extinction efficiency, asymmetrical parameter and single-scattering albedo are computed.The results are compared with those of the equivalent sphere with the equal surface-area, the equal volume and the equal volume-to-surface-area ratio. It is found that properties with respect to the same volume-to-surface-area ratio are mostly close to the reality. The influence of the aspect ratio on light scattering properties of cylinder particles with different size parameters has similarity and should be considered. In addition, there is a nodical point in the phase functions of cylinder particles with the same surface areas but different aspect ratios..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1155 (2009)
Diffraction and Gratings
Fabrication of Organic Groove-Free Gratings
Huang Yuanming, Zhou Fufang, and Zhai Baogai
Banana-shaped compound 1,3-phenylene bis(4-methoxy-benzylidene amine) was synthesized. After a tiny amount of the synthesized banana-shaped molecules were sandwiched between two pieces of glass substrates, the molecules were able to assemble themselves into organic groove-free gratings when the banana-shaped compound wBanana-shaped compound 1,3-phenylene bis(4-methoxy-benzylidene amine) was synthesized. After a tiny amount of the synthesized banana-shaped molecules were sandwiched between two pieces of glass substrates, the molecules were able to assemble themselves into organic groove-free gratings when the banana-shaped compound was cooled in air to room temperature from its melt state at about 150 ℃. Polarizing optical microscopic characterization demonstrates that these banana-shaped molecules can assemble themselves into parallel and equidistant stripes between two pieces of glass substrates with a periodic modulation of the refractive index. He-Ne laser diffraction experiment shows that although the gratings are groove-free, the self-organized optical gratings by the banana-shaped molecules exhibit the same diffraction patterns as classically ruled gratings. From the viewpoint of the steric structure of the banana-shaped molecules, the formation mechanism of the self-assembled groove-free gratings was discussed and the diffraction equation was derived for the self-assembled groove-free gratings for the organic groove-free gratings..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1160 (2009)
FFT Computation of Angular Spectrum Diffraction Formula and its Application in Wavefront Reconstruction of Digital Holography
Li Junchang
Starting from the sampling theorem,the fast Fourier transform (FFT) computation of angular spectrum diffraction formula and its inverse operation are studied. Based on the studied results,the wavefront reconstruction problem in digital holography,that is,the object light passing through an optical system and then reachStarting from the sampling theorem,the fast Fourier transform (FFT) computation of angular spectrum diffraction formula and its inverse operation are studied. Based on the studied results,the wavefront reconstruction problem in digital holography,that is,the object light passing through an optical system and then reaching CCD detector,is studied. Two methods are proposed: inverse operation tracking reconstruction of the object wave field and wavefront reconstruction in image space. Finally,the feasibility of these two methods is proved by digital holography experiments and the calculation of wavefront reconstruction..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1163 (2009)
Fiber Optics and Optical Communications
High-Speed Interfacing between Laser and Laser Driver
Cheng Mu, Wu Chongqing, Wang Dan, Sheng Jiye, and Liu Hua
The design of interface between the laser diode and its driver is important issue for high-speed fiber optic communications design. But the high speed interfacing between laser and the laser driver has few studies. The interface problem between the laser and the laser driver is reviewed. And then, the equivalent lumpedThe design of interface between the laser diode and its driver is important issue for high-speed fiber optic communications design. But the high speed interfacing between laser and the laser driver has few studies. The interface problem between the laser and the laser driver is reviewed. And then, the equivalent lumped parameter circuit models of the laser driver and the laser diode is demonstrated. Based on the theory above, the stability condition of the bias current and the modulation current is presented. At last, the directly modulated laser of 2.5 Gb/s is demonstrated in experiment..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1168 (2009)
Research on Least Number of Degrees of Freedom for Transformation among Arbitrary State of Polarizations
Zhang Xiaoguang, Duan Gaoyan, and Xi Lixia
Automatically controlled polarization controllers (PC) are important devices for treating states of polarization (SOP) of the optical signals in fibers, which are the essential integral parts in an automatic compensator for polarization mode dispersion (PMD). Two types of commercial available PCs are taken as examples Automatically controlled polarization controllers (PC) are important devices for treating states of polarization (SOP) of the optical signals in fibers, which are the essential integral parts in an automatic compensator for polarization mode dispersion (PMD). Two types of commercial available PCs are taken as examples to show theoretically and experimentally that except for the reset-free problem it is necessary to adjust at least three instead of two waveplates in order to transform any input state into any other state covering the entire Poincaré sphere. Therefore we can achieve complete PMD compensation at least using three degrees of freedom instead of two in each stage PMD compensator..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1173 (2009)
Experimental Study on Coupling High-Frequency Fiber-Optic Vibration Sensor
Ma Bin, Xu Jian, and Sui Qingmei
A new kind of coupling high-frequency fiber-optic vibration sensor and its corresponding demodulation circuit and signal process system were presented. The waveform and frequency of high-frequency vibration signals were tested, and the responses of fiber-optic sensor to different drive voltages and different directionsA new kind of coupling high-frequency fiber-optic vibration sensor and its corresponding demodulation circuit and signal process system were presented. The waveform and frequency of high-frequency vibration signals were tested, and the responses of fiber-optic sensor to different drive voltages and different directions were discussed. The influences of transmission medium shape and qualiy on the results were investigated. The experimental results show that the cutoff frequency of the coupling fiber-optic vibration sensor is 8 kHz; its amplitude measuring sensitivity is 325 mV/mm; and its frequency and amplitude response error is less than 1%..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1177 (2009)
Sensing Characteristic of Optical Fiber Refractive Index Sensor Based on Core Diameter Mismatch
Yang Jianchun, Xu Longjun, Zhang Peng, and Chen Weimin
According to Fresnel formula and power reflectance, the sensing principle of optical fiber refractive index sensor based on core diameter mismatch is analyzed. The sensor consists of a multimode fiber in which a short section of standard single-mode fiber is inserted. To validate the theoretical result, output light poAccording to Fresnel formula and power reflectance, the sensing principle of optical fiber refractive index sensor based on core diameter mismatch is analyzed. The sensor consists of a multimode fiber in which a short section of standard single-mode fiber is inserted. To validate the theoretical result, output light power of the sensor is studied by glycerin aquatic solution experiments with different refractive indexes. The results show that output light power of the sensor strongly depends on the refractive index of the external medium. The sensor exhibits output light power with no change in the refractive index range of 1.300～1.441. Output light power drops linearly in the range of 1.441～1.452, with slope of -155.91. As the refractive index of the external medium is close to that of single-mode fiber cladding, the corresponding output light power is almost zero. The glycerin aquatic solution experimental result agrees with the theoretical result, and the refractive index range of linear light power dropping is 1.442～1.454, with slope of -49.67. The method is simple and low-cost. All signals of the sensing system are transmitted by fiber. It can measure refractive index of toxic and hazardous solutions with high resolution, and is suitable for gas concentrations measurement in flammable and explosive, strong electromagnetic interference environments and other particular conditions..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1183 (2009)
Coupled-Mode Theory and Its Application to Fiber Optics
Qian Jingren
Firstly, the development and application of the coupled-mode theory in microwaves and its extension to fiber optics in the early years are briefly reviewed, and it is well known that coupling among modes is described mathematically by the coupled-mode equations which are linear differential equation group of the first Firstly, the development and application of the coupled-mode theory in microwaves and its extension to fiber optics in the early years are briefly reviewed, and it is well known that coupling among modes is described mathematically by the coupled-mode equations which are linear differential equation group of the first order. Then, it is noted that the coupled-mode equations are rigorously transformed from the Maxwell equations along with a perturbed boundary condition, the approximation methods are used when solving these equations and the order of the approximation is given. The coupled-mode method is attributed to its simplicity in principle, intuitiveness in physics and capacity of simulating complete transfer of power. Finally, a variety of applications of coupled-mode theory to fiber optics, including modeling and simulation are shortly introduced. Misuses of coupled-mode theory are also commented..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1188 (2009)
Image Processing
Blurred Image Restoration of Local Uniform Motion Based on Z Transform
Li Minghe, He Bin, Yue Jiguang, and Qin Jianming
A restoration algorithm of local uniform motion blurred image based on Z transform for invariant background motion image detection was proposed. Suppose the foreground and the background is easy to be separated from blurred image. Image foreground was extracted from blurred image based on background subtraction method.A restoration algorithm of local uniform motion blurred image based on Z transform for invariant background motion image detection was proposed. Suppose the foreground and the background is easy to be separated from blurred image. Image foreground was extracted from blurred image based on background subtraction method. Other direction movement of image foreground in the image space was converted into X axis direction movement by rotation matrix. In order to simplify the complex restoration process of local-blurred image, the whole procedure was divided into two steps: 1) image foreground restoration; 2) integration of foreground and background. Restoration and degradation model was established based on Z transform by strict mathematical deduction. Difference equation was changed into algebraic equation to simplify the solving process. Simulation results shown that the proposed method can be restored blurred image of local uniform motion correctly, effectively and rapidly. The algorithm is not sensitive to fuzzy degree; have a certain stability and superiority compared to Wiener filter restoration algorithm..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1193 (2009)
A Fast Iterative Image Reconstruction Algorithm from Few-views Projections Data
Zou Jing, Sun Yanqin, and Zhang Peng
In order to reconstruct high-quality image from projection data at few views, we develop an improved fast iterative reconstruction algorithm based on the minimization of the image total variation (TV). In the algorithm, conjugate gradient method is applied to solve the minimization of the image total variation, and mulIn order to reconstruct high-quality image from projection data at few views, we develop an improved fast iterative reconstruction algorithm based on the minimization of the image total variation (TV). In the algorithm, conjugate gradient method is applied to solve the minimization of the image total variation, and multi-resolution iterative technique is used in the iteration process. We have performed numerical experiments using both computer-simulation data and real CT data. Experimental results demonstrate that the proposed algorithm not only improves the quality of image reconstructed, but also significantly increases the convergence speed of iteration image..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1198 (2009)
Improvement of Iterative Shift-and-Add Image Reconstruction Method
Jin Zhenyu, Liu Zhong, and Qiu Yaohui
Iterative shift-and-add technique(ISA) refers one of the space domain statistical reconstruction methods. The experiments of the space domain statistical reconstruction, of which objective is the multipoint-source objective such as binary star, show that the effect of ISA is better than the speckle masking and also itsIterative shift-and-add technique(ISA) refers one of the space domain statistical reconstruction methods. The experiments of the space domain statistical reconstruction, of which objective is the multipoint-source objective such as binary star, show that the effect of ISA is better than the speckle masking and also its speed is faster than the speckle masking. ISA cannot be directly used to the high-resolution reconstruction of astronomical and space extended objective such as the sun or satellites so that this article discusses the possibilities of applying ISA to extended objective reconstruction by modification and carries out numerical simulation experiments of high resolution reconstruction of satellites under different photon noises. The simulation experiments show the improved ISA can silence photon noise and for the faint expanding objective reconstruction it has better reconstruction effect than frequency reconstruction method such as speckle masking..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1205 (2009)
Panoramic Image Mosaic Method For Rotary Scanning Serial ImageWang Huifeng
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
In the light of the special requirement of inner surface observation of cannon barrel and considering the shortage of traditional image mosaic, a kind of panoramic image mosaic method is presented combining hardware and software, which is based on rotated scanning serial inner surface image. In this method, a reflectorIn the light of the special requirement of inner surface observation of cannon barrel and considering the shortage of traditional image mosaic, a kind of panoramic image mosaic method is presented combining hardware and software, which is based on rotated scanning serial inner surface image. In this method, a reflector with 45° angle and synchronous ratation of a CCD camera driven by a step motor are used to get the equidistant serial inner surface images quickly, then the inner surface full image are coarse mosaic according to the step angle based on the serial images. During the mosaic the rotator step angle θ and the image pixel distance P calibrated first, then the sub-district to be matched are chosen according to calibrating, after that the precision matching on sub-pixel degree are implemented based on phase correlation, so mosaic of the serial images is realized in high precision. In order to obtain a smooth transition in full image seam Gaussian functions weighted amalgamation algorithm based on human visual system(HVS) character is used to blend images. Simulation and test shows that the algorithm can generate the seamless full image of the inner surface quickly and in high precision, the mosaic precision can reach sub-pixel and the time consumption is less than 500 ms,which can meet the real-time observation requirement, and suit to engineering application..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1211 (2009)
Fast Macroblock Mode Decision Algorithm for Multiview Video Coding Based on Mode Correlation
Peng Zongju, Jiang Gangyi, and Yu Mei
In order to reduce computational complexity of multiview video coding, a fast macroblock mode selection algorithm is proposed. On the basis of a detailed analysis of the distribution and rate-distortion features of macroblock modes in joint multiview video model (JMVM), conceptions of macroblock mode correlation and moIn order to reduce computational complexity of multiview video coding, a fast macroblock mode selection algorithm is proposed. On the basis of a detailed analysis of the distribution and rate-distortion features of macroblock modes in joint multiview video model (JMVM), conceptions of macroblock mode correlation and mode aggregative degree are put forward. The analysis of the macroblock mode correlation of the test sequence shows that the optimal mode of the current macroblock is the same as that of the most neighboring macroblocks. The precision of the macroblock mode prediction is explored from the angle of the aggregative degree of the neighboring macroblock regions. In the implementation of the fast algorithm, a threshold formed by the average rate distortion cost of the neighboring macroblocks determines the necessity for full searching all macroblock modes. Experimental results demonstrate that the proposed fast algorithm promotes the encoding speed by 2.43～4.08 times in comparison with JMVM, while the rate distortion performance nearly remains same..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1216 (2009)
Target Recognition Based on Wavelet Multiscale Product
Chen Fanghan, Miao Hua, Chen Yu, and Wang Wensheng
Optical correlation detection can discriminate target from clutter scene by the optical method to realize target recognition. Wavelet transform is applied to hybrid optoelectronic joint transform correlator (HOJTC), it transcends the limitation of Fourier transform, and can analyze detected target in different quartersOptical correlation detection can discriminate target from clutter scene by the optical method to realize target recognition. Wavelet transform is applied to hybrid optoelectronic joint transform correlator (HOJTC), it transcends the limitation of Fourier transform, and can analyze detected target in different quarters and scales. To exploit character of various scales, the method of wavelet multiscale product is proposed to extract edge feature of image. This method considers the detail and contour as well, and combines both of them at different levels. The problem of targets recognition with insufficient information is settled. Optical experimental results show that the method effectively enhances the energy of correlation peaks of target in clutter scene, successfully realizes target detection, and has a good prospect of application..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1223 (2009)
Object Detection Algorithm Based on Moving Background in MPEG-4 Video
Tian Yumin, Wan Bo, and Dong Wentao
Focusing on the problem of moving object detection in moving camera, a new method for the estimation of global motion from compressed image sequences is proposed. With the global motion estimation as basis, utilizing the similarity of the background micro blocks, the algorithm can build background micro blocks sets speFocusing on the problem of moving object detection in moving camera, a new method for the estimation of global motion from compressed image sequences is proposed. With the global motion estimation as basis, utilizing the similarity of the background micro blocks, the algorithm can build background micro blocks sets speedily. Adopting the common four-parameter global motion estimation model, the motion parameters are estimated. By computing and filtering the motion vectors residual, the moving object is detected. The algorithm can utilize the motion information contained in the MPEG-4 video coded stream without decoding the coded stream completely, so it can improve the detection efficiency and effect dramatically.Testing results validate its advantages in global motion estimation..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1227 (2009)
Moire Tomography Based on Phase Reconstruction
Song Yang, Chen Yunyun, He Anzhi, and Zhao Zhimin
According to the problem that processing moiré fringes based on phase reconstruction methods in moiré deflection tomography, the formation of moiré fringes is analyzed from the scalar diffraction theory. The zero-and first-order frequency spectrum is extracted respectively by pinhole filtering. Compared According to the problem that processing moiré fringes based on phase reconstruction methods in moiré deflection tomography, the formation of moiré fringes is analyzed from the scalar diffraction theory. The zero-and first-order frequency spectrum is extracted respectively by pinhole filtering. Compared with results from the traditional geometric superposition principle of moiré effect, Result in this paper fits well and has a more accurate form. Results show that the moiré fringes are generated by shearing interference of multiple wave fronts and moiré patterns with first-order filtering are the strict cosinusoidal intensity distribution. Finally, the combustion of propane in the air is reconstructed by using the Fourier transform method which based on multi-grid phase unwrapping algorithm and the filtered back-projection algorithm of moiré tomography..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1232 (2009)
Fusion Algorithm of Multi-Spectral and High-Resolution Images Based on Region Feature in NSCT Domain
Ye Chuanqi, Wang Baoshu, and Miao Qiguang
An fusion algorithm for multi-spectral and high-resolution images based on multi-level threshold segmentation and the nonsubsampled contourlet transform (NSCT) is proposed. Multi-level threshold segmentation is done for the multi-spectral image, and notions about ratio of region mean (RRM) are used to divide the multi-An fusion algorithm for multi-spectral and high-resolution images based on multi-level threshold segmentation and the nonsubsampled contourlet transform (NSCT) is proposed. Multi-level threshold segmentation is done for the multi-spectral image, and notions about ratio of region mean (RRM) are used to divide the multi-spectral image into the areas which need to be spatially enhanced and need to preserve spectral characteristics. Then the NSCT is performed on the high-resolution image and the intensity component of the multi-spectral image at different scales and directions. The low-frequency coefficients are fused with the windows-based fusion rules and operators, and the high-frequency coefficients are fused with the region-based rules according to the RRM. Finally the fused coefficients are reconstructed to obtain the fused intensity component of the multi-spectral image, and the inverse IHS transform is performed to get the fused multi-spectral image. Experimental results show that the algorithm proposed performs significantly better than the IHS transform, the pixel-based à trous wavelet transform and the pixel-based NSCT..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1240 (2009)
Improved algorithm for 2-D Empirical Mode Decomposition in Image Processing
Zhang Heyong, Ren Deming, Zhao Weijiang, and Qu Yanchen
An improved algorithm of 2-D empirical mode decomposition (EMD) in image processing has been presented. It contains selecting extrema of the pixels and interpolation of them in the course of EMD, in which a variance phenomenon of boundary pixels has been discovered. Delaunay triangulation has been used to partition theAn improved algorithm of 2-D empirical mode decomposition (EMD) in image processing has been presented. It contains selecting extrema of the pixels and interpolation of them in the course of EMD, in which a variance phenomenon of boundary pixels has been discovered. Delaunay triangulation has been used to partition the selected extrema, then replaces the pixels that not contained in the Delaunay polygon through symmetry principle, which can restrain the variance phenomenon that appeared in the cubic spline interpolation. An image has been processed with the improved algorithm, and the result indicates that the standard deviation between the original image and the reconstructed image is 6.667×10-6 . The reconstructed image is in good agreement with the original image. It demonstrates that the improved algorithm presented is accurate and feasible. The application of method of EMD is more and more popular in image compression and de-noising, therefore, the improved algorithm will increase the calculation speed of image processing based on EMD..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1248 (2009)
Imaging Systems
Comparison and Application of Motion Compensation Algorithms in Video Stabilization
Yao Jun, Jiang Xiaoyu, Du Dengchong, and Wang Xi
Motion compensation algorithms are compared and analyzed, including Kalman filter algorithm, average filter algorithm, Gaussian kernel filter algorithm, parabolic fitting algorithm, and damping coefficient algorithm. Motion estimation vectors of several fluctuated video are obtained by Laplacian bit-plane method, whichMotion compensation algorithms are compared and analyzed, including Kalman filter algorithm, average filter algorithm, Gaussian kernel filter algorithm, parabolic fitting algorithm, and damping coefficient algorithm. Motion estimation vectors of several fluctuated video are obtained by Laplacian bit-plane method, which are utilized to test the above compensation algorithms. The conclusion for the preceding five algorithms conduces to select appropriate motion compensation algorithms in video stabilization. It is verified that damping coefficient algorithm is a quite effective algorithm, except that its damping coefficient can not be adjusted automatically. An improved adaptive damping coefficient algorithm is presented, which is more robust and effective..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1254 (2009)
Design and Analysis of New Diffractive Optic Imaging Spectrometer
Yu Bin, Chen Danni, Sun Qiang, Qu Junle, and Niu Hanben
To avoid the shortcoming of magnification change with wavelength, which will cause the spectral image pixel registration error and provide inaccurate relative spectral signal strength in the classical diffractive optic imaging spectrometer, a novel hybrid refraction/diffraction telecentric optical system combining a diTo avoid the shortcoming of magnification change with wavelength, which will cause the spectral image pixel registration error and provide inaccurate relative spectral signal strength in the classical diffractive optic imaging spectrometer, a novel hybrid refraction/diffraction telecentric optical system combining a diffractive lens with an achromatic lens system is presented, and the working principle is then established. Furthermore, the concrete design example for visible/near-infrared imaging spectrometer is analyzed and evaluated with optical design software Zemax. The results prove the proposed method is valid and feasible. The shortcoming is overcome successfully, and the difficulty of the manufacturing process of the diffractive lens is also reduced. The theoretical and practical guidance is thereby provided for the study, design and engineering of the new diffractive optic imaging spectrometer with constant magnification..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1260 (2009)
Vertically Integrated Diode for CMOS Color Image Sensor and Its Colorimetric Characterization
Chen Yuan, Xu Zhihai, and Feng Huajun
The vertically integrated diode can sense blue and red illumination simultaneously, and can provide full color information with green/magenta filter on it. It can also be used in the CMOS image senor for its fully compatibility with standard CMOS process. Through extraction of photogenerated carriers at different depthThe vertically integrated diode can sense blue and red illumination simultaneously, and can provide full color information with green/magenta filter on it. It can also be used in the CMOS image senor for its fully compatibility with standard CMOS process. Through extraction of photogenerated carriers at different depths by vertically integrated diode with two color filters, the full color image is got. Through simulation and experiment, each channals response curve is got, an enhanced sound-robust method with multi-polynomial regression is proposed, and the color space transform matrix is obtained. The sensors four-channel response is converted to CIE XYZ three-stimulus-values. In the CIE L*A*B* space, comporation between cooridinate and sensed color coordinate is proposed, and the apparatus color accuracy is quantitively evaluated. The result shows that the device colorimetric accuracy is superior to that of a simple linear transformation, even better than commercial colorful CCD with Bayer filter..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1264 (2009)
Range Resolution Improvement of Scannerless Laser Radar
Zhang Yong, Zhao Yuan, Liu Liping, Zhang Yu, and Sun Xiudong
The signal-to-noise-ratio (SNR) of the existing scannerless laser radar detector array is relatively low, which affects the range resolution of the system. The noise characteristics of the detector arrays were analyzed. It is pointed out that, the noise is ergodic and the SNR of range detector can be increased by usingThe signal-to-noise-ratio (SNR) of the existing scannerless laser radar detector array is relatively low, which affects the range resolution of the system. The noise characteristics of the detector arrays were analyzed. It is pointed out that, the noise is ergodic and the SNR of range detector can be increased by using spatial domain accumulation in place of time-domain accumulation. According to this conclusion, an image processing method using the neighborhood averaging image processing method is proposed, which can improve range resolution of scannerless ladar system, specially for the scannerless laser radar/TV composite imaging system. The practical application in real system shows this method can effectively increase the range resolution of scannerless ladar system..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1270 (2009)
Measurement Method of X-ray Focus Projection Coordinates of Three-Dimensional Micro-Computerized Tomography Scanning System
Yang Min, Liu Jinghua, Li Baolei, Wu Wenjin, and Wang Gang
In the three-dimensional micro-computerized tomography scanning system, it is impossible to measure the positions of the X-ray focus and imaging plane of the detector by direct means. A simple and feasible method to measure the X-ray focus projection coordinates with high accuracy is proposed. This method is based on tIn the three-dimensional micro-computerized tomography scanning system, it is impossible to measure the positions of the X-ray focus and imaging plane of the detector by direct means. A simple and feasible method to measure the X-ray focus projection coordinates with high accuracy is proposed. This method is based on the theory that the projection of the sphere object in the cone-beam field is an ellipse. Through acquiring the digital radiography images of the double sphere objects, the image and graphics processing methods and the least square fitting method are used to get the intersection point of the major axis of the two ellipses. The intersection point is also the X-ray focus projection on imaging plane of the detector. The experimental results prove that the accuracy of this method can satisfy the requirements of the practical micro-comptuterized tomography scanning system, and is easy to realize with high anti-noise ability..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1275 (2009)
Instrumentation, Measurement and Metrology
Error Analysis of on-Line Temperature-Field Measurement by Infrared CCD
Yang Junwei, Hu Zhongxiang, Shi Xiaojun, and Qian Yaochuan
The temperature-field information collected by infrared CCD is usually interfered by various measurement errors, including optical system error, CCD error and infrared radiation interference. Errors induced by optical system and CCD can usually be controlled by image processing techniques. However, these techniques canThe temperature-field information collected by infrared CCD is usually interfered by various measurement errors, including optical system error, CCD error and infrared radiation interference. Errors induced by optical system and CCD can usually be controlled by image processing techniques. However, these techniques can hardly deal with infrared radiation interferences due to their high randomness. To solve this problem, a series of thermo-couples were preset to monitor temperatures at fixed points, which were used to calibrate the system emissivity. Real-time measurement of temperature field was thus achieved based on the modified system emissivity. The mathematical model and system of calibration are established to prevent the sudden change of temperature with system emissivity. Error and mutation of the on-line temperature field measurement are eliminated. The test results show the feasibility of the calibration system of on-line temperature-field measurement..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1281 (2009)
Quantitative Analysis for Nonlinear Fluorescent Spectra Based on Principal Component Analysis
Chen Yang, Zhang Taining, Guo Peng, Wang Xianghui, Wang Qian, and Chang Shengjiang
A pre-process, feature extraction and quantitative analysis approach based on principal component analysis (PCA) is proposed to analyze the complicated nonlinear fluorescent spectra, emitted by the interaction between femto-second(fs) laser and the impurities in air. The spectral data is denoised and compressed from 39A pre-process, feature extraction and quantitative analysis approach based on principal component analysis (PCA) is proposed to analyze the complicated nonlinear fluorescent spectra, emitted by the interaction between femto-second(fs) laser and the impurities in air. The spectral data is denoised and compressed from 3979 to 664 points using wavelet transform (WT). By fitting the feature peaks of the compressed spectra with different concentration impurities using PCA, the monotone relation between intensity and concentration is identified and it can be used to perform quantitative analysis. Simulation results on three kinds of impurities with low concentration show that the first two principal components can cover 98% information, and the quantitative analysis method based on the first principal component can effectively reduce the error from 0.2694 to 0.02 compared with previous method..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1285 (2009)
Lasers and Laser Optics
Tunable Mode-Locked Pulsed Erbium-Doped Fiber Ring Laser
Song Chuangxing, Xu Wencheng, Luo Zhichao, Chen Weicheng, Gao Yuxin, and Liu Songhao
A simple,stable wavelength tunable passively mode-locked erbium-doped fiber ring laser is reported. The nonlinear polarization rotation effect is used, as equivalent saturable absorber, to achieve the self-starting mode-locking in the laser. The wavelength tuning can be realized by simply rotating the orientation of poA simple,stable wavelength tunable passively mode-locked erbium-doped fiber ring laser is reported. The nonlinear polarization rotation effect is used, as equivalent saturable absorber, to achieve the self-starting mode-locking in the laser. The wavelength tuning can be realized by simply rotating the orientation of polarization controllers. The output of the laser is taken via a wideband coupler, whose operating wavelength is 1550±50 nm. Experimentally, low self-starting threshold mode-locked pulses at 10.23 MHz repetition rate were obtained. The output wavelength was continuously tunable from 1548.64 nm to 1600.24 nm, and the side-mode suppression ratio was beyond 44 dB..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1292 (2009)
Research of Scattering Intensity with Spherical Particles in Laser Cladding
Dong Zhe, and Yang Xichen
In order to analyze the interaction of laser and spherical particles in coaxial laser cladding, the physical model of laser scattering by spherical particles is established by using Mie scattering theory in certain assumptions, which will help select the laser and the spherical powder.The distributions of laser intensiIn order to analyze the interaction of laser and spherical particles in coaxial laser cladding, the physical model of laser scattering by spherical particles is established by using Mie scattering theory in certain assumptions, which will help select the laser and the spherical powder.The distributions of laser intensity with radius of particles and wavelength of laser were drawn by Mathematica software. The simulated results were analyzed. The results show the particles radius and laser wavelength are important parameters affecting the distribution of scattering intensity. There is a secondary maximum with direction deviation beyond 20° as the optical factor is less than 30. It accounts for a higher proportion of scattered light intensity, and it is adverse to the formation of molten pool. The scattering intensity is concentrated in the range from 5° to 6° as the optical factor is more than 30, and the scattering intensity is very strong in this range, which will promote laser cladding..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1296 (2009)
Stability Analysis of Beat Frequency in Double-Longitudinal-Mode He-Ne Laser
Liang Jing, and Long Xingwu
The stability of beat frequency in the double-longitudinal-mode He-Ne laser is discussed. Considering the mode-pulling effect, the relation between the stability of the single mode and that of the beat frequency is deduced theoretically. The stability of the beat frequency in 632.8 nm He-Ne laser is 1000 times of that The stability of beat frequency in the double-longitudinal-mode He-Ne laser is discussed. Considering the mode-pulling effect, the relation between the stability of the single mode and that of the beat frequency is deduced theoretically. The stability of the beat frequency in 632.8 nm He-Ne laser is 1000 times of that of the single mode with the frequency pulling parameter of 10-3. The experimental results show that the stability of the beat frequency is 3.3×10－6, when the single-mode stability reaches 1×10－9..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1301 (2009)
Evolutionary Rules of Time Modulation and Intensity of Stacked Chirped Pulses
Liu Lanqin, Lin Honghuan, Peng Zhitao, Su Jingqin, Wang Jianjun, Hu Dongxia, Jing Feng, and Zhang Xiaomin
The broadband nanosecond shaped laser pulse obtained by chirped pulse stacking(CPS) method can make the output stacking pulse meet the requirement of the inertial confinement fusion (ICF), and CPS is the main technique way adopted in front end systems in some laser facilities. However, temporal pulse shape modulation wThe broadband nanosecond shaped laser pulse obtained by chirped pulse stacking(CPS) method can make the output stacking pulse meet the requirement of the inertial confinement fusion (ICF), and CPS is the main technique way adopted in front end systems in some laser facilities. However, temporal pulse shape modulation will exist due to the pulse coherence for chirped stacking pulse, and spectrum modulation will exist too. Moreover, the peak intensity of this stacked chirped pulses will change rapidly under different influence conditions. The evolutionary rules of the temporal pulse shape modulation, spectrum modulation and the intensity factor are reported. The results show the temporal pulse shape modulation is affected by the broadening factor and the delay time, as spectrum modulation is only affected by the delay time, and the intensity factor changes similarly with the cosine function of the phase factor..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1305 (2009)
Radiometric Characteristics Test of Integrating Sphere Source Using Wavelength-Tunable Laser
Xu Qiuyun, Zheng Xiaobing, Zhang Wei, and Li Jianjun
To reduce the calibration uncertainty of spectral radiance responsivity, a new tunable laser-based integrating sphere source was developed. In this facility, high-power, tunable laser outputs were introduced into an integrating shpere, producing uniform, quasi-Lambertian, high radiant flux planar source. Ti:sapphire laTo reduce the calibration uncertainty of spectral radiance responsivity, a new tunable laser-based integrating sphere source was developed. In this facility, high-power, tunable laser outputs were introduced into an integrating shpere, producing uniform, quasi-Lambertian, high radiant flux planar source. Ti:sapphire laser 710 nm output light was used to study the radiometric characteristics of the source. While two-beam paths were introduced into the sphere and laser speckle was eliminated, the radiance instability was 0.06% in 30 min; the radiance was spatially uniform within 0.16% over the most central region 60 of the sphere exit port; the angular nonuniformities in horizontal and vertical plane within the range of ±22° were 1.3% and 0.7% respectively. This source have the advantages of high stability, high spectral radiant flux, narrow bandpass, large area, tunable wavelength in broad spectral range, etc. The radiometric properties of the source couple with state-of-the-art standard detector whose responsiveness are directly traceable to primary radiometric scales can reduce the calibration uncertainty effectively..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1310 (2009)
Materials
Preparation and Spectroscopic Characterization of ZnO/MCM-41 Composite
Wang Guangjian, Guo Yajie, Yang Zhenxing, Xu Mingxia, and Chen Shifu
In alkaline condition, the mesoporous molecular sieve MCM-41 was synthesized by the hydrothermal reconstruction method with sodium silicate as the silion source and cetyltrimethylammoniumbromide (CTAB) as the surfactant template. The MCM-41 supported nano-ZnO composite was prepared with mesoporous material molecular siIn alkaline condition, the mesoporous molecular sieve MCM-41 was synthesized by the hydrothermal reconstruction method with sodium silicate as the silion source and cetyltrimethylammoniumbromide (CTAB) as the surfactant template. The MCM-41 supported nano-ZnO composite was prepared with mesoporous material molecular sieve MCM-41 as carrier and heating the Zn(Ac)2-loaded MCM-41. The structures of ZnO/MCM-41 composite were characterized by scanning electro microscope, photoluminescence spectroscopy, infrared spectroscopy, N2 absorption-desorption and UV-Vis absorption spectroscopy. The result showed that the diameter of mesoporous molecular sieve was 1.7 \mm. The spectroscopic characterization of the ZnO/MCM-41 synthesised at different temperatures was studied. It was shown that the size of MCM-41 was limited and the size of ZnO was smaller than 2 nm. Owing to the quantum-size effect, the UV-Vis absorption and fluorescence of the nano-ZnO particles were blue-shifted distinctly. By the infrared spectroscopy, the skeleton of mesoporous molecular sieve was not changed after loading ZnO on MCM-41..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1315 (2009)
Exciton Energy Levels of (nc-Si/SiO2)/SiO2 Multi-Layer Quantum Dots Structure
Chen Libai, Guo Zhenning, and Yang Xiaoru
The exciton energy levels and wave functions of (nc-Si/SiO2)/SiO2 multi-layer structure are analyzed, by using the spherical quantum dots model and effective mass approximation theory. The model of finitely deep potential well makes the resuct more accurate and near to reality. The conclusion shows that the ground. StaThe exciton energy levels and wave functions of (nc-Si/SiO2)/SiO2 multi-layer structure are analyzed, by using the spherical quantum dots model and effective mass approximation theory. The model of finitely deep potential well makes the resuct more accurate and near to reality. The conclusion shows that the ground. State energy of mass center′s motional part increases rapidly as the radius of quantum dot decreases, no matter in infinitely deep potential well or finitely deep potential well. The mass center energy in infinitely deep potential well is always higher than the finitely deep potential wells with same radius of quantum dot, and their differences increase as the radius of quantum dot decreases..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1320 (2009)
Raman Studies on Ni-Doped ZnO Powders
Yu Huiqiang, Li Binbin, Zhang Rong, Xiu Xiangqian, Xie Zili, Ye Yuda, Zhang Mengqun, Chen Qiang, and Shen Jiancang
Raman spectrum is performed to study the phonon modes of Ni-doped ZnO powders. The phonon mode of undoped ZnO and two additional modes (AMs) have been observed in the Raman spectra of doped swatch. The observation of E2(h) phonon mode in the samples indicates that the doped ZnO powders still keep the hexagonal structurRaman spectrum is performed to study the phonon modes of Ni-doped ZnO powders. The phonon mode of undoped ZnO and two additional modes (AMs) have been observed in the Raman spectra of doped swatch. The observation of E2(h) phonon mode in the samples indicates that the doped ZnO powders still keep the hexagonal structure. The AM at 652 cm-1 is ascribed as local vibrational mode due to the host defects. In order to identify the origin of the AM at 544 cm-1, Raman spectrums of the Ni-, Co-, and Mn-doped ZnO powders have been carried out respectively. The results show that the AM at 544 cm-1 is related to Ni impurity. Origins of other phonon modes in the spectra are discussed as well. The multi-LO phonons scattering observed by an exciting source of 325 nm on Ni-doped ZnO powders is reported..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1324 (2009)
Study on Spectral Characteristics of Correlated Photon Pairs Based on Photon Crystal Fiber
Li Xibin, Chai Lu, Zhang Yuying, Li Xiaoying, and Wang Qingyue
The phase-matching function and spectral function of spontaneous four-wave mixing in the fiber pumped by picoseconds pulse are derived, to study spectral characteristics of correlated photon pairs at 800 nm based on photon crystal fiber (PCF), The calculation result shows that the optimized spectral symmetry can be achThe phase-matching function and spectral function of spontaneous four-wave mixing in the fiber pumped by picoseconds pulse are derived, to study spectral characteristics of correlated photon pairs at 800 nm based on photon crystal fiber (PCF), The calculation result shows that the optimized spectral symmetry can be achieved by choosing the idler wavelength at 796 nm in the fiber. By using the simplified spectral function, the evolved effects and changing law of the signal light and idle light, were discussed under the condition of the idler light with a single frequency, by changing the dispersion slope at the zero dispersion wavelength, the nonlinear coefficient and the central wavelength of pump pulse. Parameters in favor of high purity photon pairs were presented. These results provide reference for developing entangled photon sources based on photon crystal fiber at 800 nm wave band..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1368 (2009)
Tunable Slow Light by Electro-Eptic Effect in Polymer Photonic Crystal Waveguide
Wang Xueying, Tian Huiping, Li Changhong, and Ji Yuefeng
All-optical buffers have been considered as essential components for all-optical communications. Considering the requirements of controllable optical delay lines and optical buffers, the external dynamic tuning of slow light in photonic crystal waveguides has been studied. A novel photonic crystal waveguide on polymer All-optical buffers have been considered as essential components for all-optical communications. Considering the requirements of controllable optical delay lines and optical buffers, the external dynamic tuning of slow light in photonic crystal waveguides has been studied. A novel photonic crystal waveguide on polymer substrate is proposed. Numerical study using plane, wave expansion method shows that this structure supports a single guided mode transmission,which allows a low group velocity of 10-2c in the vicinity of band edge. Since the substrate material possesses a high electro-optic coefficient and a subpicosecond nonlinear response time, and local field effect induced the by slow light transmission can enhance electro-optic effect greatly, these properties offer the opporunity to tune the slow light mode in wide frequency range with low power. Numerical analysis shows that by applying an external voltage of 80 V, the guided mode will shift 80.8 nm, and moreover the wavelength shift is nearly linearly increased with the increas of applied modulated voltage. Modulation sensitivity is about 1 nm/V. The flexible dynamical tuning of slow light mode can meet the requirements for the use of optical buffer in all-optical network in principle..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1374 (2009)
Medical Optics and Biotechnology
Study on Autofluorescence Spectral Feature for Cancer Cell in Different Stages of Cell Cycle
Lin Xiaogang, Pan Yingjun, and Guo Yongcai
In order to study the autofluorescence spectral changes during cancer cell cycle, the autofluorescence spectrum of synchronically cultured HeLa cell in the G1, S, G2 and M portions of the cell cycle is measured. The results show that there is autofluorescence phenomenon during the cell cycle and the fluorescence intensIn order to study the autofluorescence spectral changes during cancer cell cycle, the autofluorescence spectrum of synchronically cultured HeLa cell in the G1, S, G2 and M portions of the cell cycle is measured. The results show that there is autofluorescence phenomenon during the cell cycle and the fluorescence intensity in each stage is different. The fluorescence sptectrum exhibits the characteristic peaks at 360 nm and 680 nm. The changes of fluorescent molecules (such as aromatic amino acid and porphyrin) in HeLa cells during the cell cycle result in these differences. The fluorescence spectra of different stages reflect the changes of aromatic amino acid and porphyrin in cell during the cell cycle and can be utilized to study the state of the cancer cell cycle..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1328 (2009)
Nonlinear Optics
Optical Nonlinear Properties of CdSeS Quantum Dot
Zhao Lilong, Wu Feng, Tian Wei, and Li Chuanqi
The optical nonlinear properties of CdSeS quantum dots (QDs) are investigated by Z-scan technique using the model locked Nd∶YAG laser second harmonic radiation (λ wavelength of 532 nm, pulse width of 35 ps). The experimental results show that the quantum dots have large two-photon absorption (TPA) which originates fromThe optical nonlinear properties of CdSeS quantum dots (QDs) are investigated by Z-scan technique using the model locked Nd∶YAG laser second harmonic radiation (λ wavelength of 532 nm, pulse width of 35 ps). The experimental results show that the quantum dots have large two-photon absorption (TPA) which originates from the third order optical nonlinearity effect. According to the absorption and fluorescence spectra, it is found that this nonlinear absorption originates from the TPA of CdSeS quantum dots. Z-scan curve of CdSeS quantum dots is measured under different incident intensities, and the experimental results show that the quantum dots have nonlinear refractive index of 1.9×10-8 esu and average TPA cross section of 25283 GM, which are two orders higher than values of commonly used ZnS QDs..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1332 (2009)
Electric-Field-Induced Linear Electro-Optic Effect in Silicon
Chen Zhanguo, Zhao Jianxun, Zhang Yuhong, Jia Gang, Liu Xiuhuan, Ren Ce, Wu Wenqing, Sun Jianbo, Cao Kun, Wang Shuang, and Shi Bao
Based on classical polarization theory, the change of refractive index of silicon is analyzed when direct-current (dc) electric field, alternating-current (AC) modulation electric field, and optical field exist simultaneously, and the physical nature of the electric-field-induced linear electro-optic effect is theoretiBased on classical polarization theory, the change of refractive index of silicon is analyzed when direct-current (dc) electric field, alternating-current (AC) modulation electric field, and optical field exist simultaneously, and the physical nature of the electric-field-induced linear electro-optic effect is theoretically indicated. Near-intrinsic silicon is constructed into a metal-insulator-semiconductor sample, and a transverse electro-optic modulation system composed of the modified Senarmont compensator is applied. The obvious linear electro-optic modulation signal is observed in the space charge region of silicon, and the half-wave voltage of the modulation system less than 170 V is estimated. The electric-field-induced linear electro-optic effect caused by the built-in electric field in silicon is experimentally demonstrated. In addition, the secondary electro-optic modulation signal generated by Kerr effect, and electric signal which changes with the cosine function of double azimuth of the linear polarizaed light and is induced by electric-field-induced optical rectification, are measured. These results are in good accordance with the classical polarization theory, and demonstrate the electric-field-induced linear electro-optic effect indirectly..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1336 (2009)
A Novel Focus Servo Module in Hybrid Magneto-Optical Recording Testing System
Chen Lu, Xu Wendong, and Zhu Qing
The design and establishment of focus servo module in the hybrid magneto-optical recording system are presented. The servo module, which acquires focus error signal through astigmatism method and utilizes the double-laser method integrated with red-laser servo and blue-laser assisted recording, serves as an independentThe design and establishment of focus servo module in the hybrid magneto-optical recording system are presented. The servo module, which acquires focus error signal through astigmatism method and utilizes the double-laser method integrated with red-laser servo and blue-laser assisted recording, serves as an independent dynamic focus servo unit. Thus, with the feature of modularization and palatability, the servo module can be used in both stable and dynamic laser recording system, in both horizontal type and vertical type optical system. For control algorithm design, the amplitude-frequency and phase-frequency characteristics and the nonlinear hysteresis of PZT are studied in detail. High accuracy dynamic focus servo is realized through PI closed-loop control with the inverse system and inverse hysteresis model calibration. Focus error is within ±130 nm under the rotate speed 8 r/s, and the diameter and depth of recording spots are almost uniform..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1341 (2009)
OPTICAL DATA STORAGE
Two-Photon Three-Dimensional Optical Data Storage with Equal Exposure Energy and Time Increase
Tang Huohong, Xing Hui, Huang Wenhao, and Zhang Fushi
Intensity of laser focus was simulated in the condition of refractive index mismatch (n=1.48, NA=0.65) at different recording depth with two-photon writing based on Torok’s theory,in order to increase the readout signal intensity of deep layer bits and the memory capacity of two-photon 3D optical data storage. The relaIntensity of laser focus was simulated in the condition of refractive index mismatch (n=1.48, NA=0.65) at different recording depth with two-photon writing based on Torok’s theory,in order to increase the readout signal intensity of deep layer bits and the memory capacity of two-photon 3D optical data storage. The relationship between the square of the maximum intensity at laser focus and the recording depth was acquired. Based on atomic absorption theory, the relationship between the exposure time and the recording depth in the condition of equal exposure energy without recording power changed was acquired. According to the results and using home-made two-photon 3D optical data memory system, the contrast experiment of recorded bits in eight consecutive layers with equal exposure energy and excitation time increasing was done in a photochromic storage medium. The experimental result indicates that the memory capacity is increased and the readout signal intensity in deep layer is enhanced effectively..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1347 (2009)
Optical Design and Fabrication
Control Construction Functions of Digital-Control Fabrication for Multilayer Dielectric Thin Film Reflector for Spectral Reshaping
Li Ming, Zhang Bin, Dai Yaping, Wang Tao, Fan Zhengxiu, and Huang Wei
In order to compensate the gain-narrowing and gain-saturation effects and improve the signal-to-noise ratio (SNR) of the output high-power laser pulse, attentions have been paid to the spatial distribution, the temporal profile, and the spectral reshaping in the design of kilo-joule peta-watt chirped pulse amplificatioIn order to compensate the gain-narrowing and gain-saturation effects and improve the signal-to-noise ratio (SNR) of the output high-power laser pulse, attentions have been paid to the spatial distribution, the temporal profile, and the spectral reshaping in the design of kilo-joule peta-watt chirped pulse amplification (CPA) systems. The multilayer dielectric thin film reflector fabricated by top-down nano-fabrication processes can be used to realize spectral reshaping of high-power chirped pulse. In the design and fabrication of the multilayer dielectric thin film reflector, it is necessary to determine the fabrication control functions appropriately. The control construction function of digital-control fabrication and the etching depth construction functions of the multilayer dielectric thin film reflector for spectral reshaping of chirped pulse laser in Shengguang-Ⅱ system are investigated. The spectral modulation properties of the multilayer dielectric thin film reflector have been analyzed, and the effect of the reflectivity distribution of the multilayer dielectric film reflector approaching to the object function has also been observed..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1352 (2009)
Optical Devices
Fabrication of Step Filter for Miniature Wavelength-Division Device Based on Photolithography
Wang Shaowei, Chen Xiaoshuang, and Lu Wei
The combinatorial etching technique based on photolithography has been used to fabricate step filters in this paper, in order to eliminate the size limit and shadow effect of mechanical masks. A step filter with 16\X1 channels for miniature wavelength-division device has been fabricated successfully. The width of a filThe combinatorial etching technique based on photolithography has been used to fabricate step filters in this paper, in order to eliminate the size limit and shadow effect of mechanical masks. A step filter with 16\X1 channels for miniature wavelength-division device has been fabricated successfully. The width of a filter element is only 90 μm and the total size of the wavelength-division device is less than 2 mm. The filter channels distribute from 632.4 nm to 739.6 nm with bandwidth narrower than 2.9 nm and transmittance higher than 70%. The filter element size of the step filter can be as small as in micro scale and the shadow effect of mechanical masks can be decreased to micro or sub-micro scale. Such step filters match with CCD completely and can be used as miniature wavelength-division device to compose a miniature spectral system for space applications etc..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1358 (2009)
Experimental Research on the Mechanism of Causing Fast Luminous Attenuation of White Lamp-LED
Wu Haibin, He Sumei, and Wang Changling
The life of many white lamp-LEDs manufactured inland is normally short. This is very different from power white LEDs. The white lamp-LEDs for different aging period have been anatomized. The variety of structure materials in package has been discussed, in order to find the real reason for leading to fast lumen attenuatThe life of many white lamp-LEDs manufactured inland is normally short. This is very different from power white LEDs. The white lamp-LEDs for different aging period have been anatomized. The variety of structure materials in package has been discussed, in order to find the real reason for leading to fast lumen attenuation of the white LED, based on the past research work. By experiments, two phenomena have been found. the first is die attaching resin has been yellowed in some LEDs, the second is that there is a thin layer of deep yellow film on the top of blue dies. Then the blue dies after wiping off the die attaching resin or the thin yellow film have been packaged again, and luminous flux show a dramatic enhancement. Blue dies touch resin mixing phosphor and die attaching resin directly, and is surrounded by them. So the performance variation of two kind of resin has important and direct effect on luminous attenuation of white lamp-LEDs..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1363 (2009)
Physical Optics
Optical Resonance for Subwavelength Ag Particle/Hole
Yang Jingjing, Huang Ming, Wu Zhongyuan, Zong Rong, and Peng Jinghui
Based on effective permittivity theory of heterogeneous material, the effective complex permittivity of two-dimensional subwavelength Ag particle/hole has been simulated. The optical resonance properties of Ag particle/hole are verified. For the Ag particle-dielectric composite structure, the effective permittivity hasBased on effective permittivity theory of heterogeneous material, the effective complex permittivity of two-dimensional subwavelength Ag particle/hole has been simulated. The optical resonance properties of Ag particle/hole are verified. For the Ag particle-dielectric composite structure, the effective permittivity has a negative real part when the optical frequency is larger than the plasmon frequency of Ag. The imaginary part of the effective permittivity shows a resonance near the plasmon frequency of Ag, and the resonance peak displays a red shift with the increase of radius of Ag particle. By calculating the electric field distribution, it is found that optical resonance results in very strong local field enhancements around the Ag particle at the resonant frequency. Similar phenomena are observed for the structure of Ag block with a single hole filled with different materials, and resonant peak shows red shift with the increase of permittivity in the hole, while the resonant peak is blue-shifted with the increase of radius of the hole filled with the same material. In addition, the optical resonance can be controlled by adjusting the size and geometry of the particle/hole. Therefore, the mechanisms for the interaction of light with particle/hole are surface plasmon mode and resonant mode, and the effective-medium theory is a powerful tool for exploring the intriguing enhanced optical transmission phenomena..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1379 (2009)
Laser Breakdown-Generated Sound in Different Optical Focusing Lens Systems
Zong Siguang, and Wang Jiangan
When high-power laser is focused in water through an optical focusing lens system, the water is broken down and high-power acoustic wave is emitted. The different optical focusing lens system relates to different acoustic waveform characteristic, such as the sound pressure intensity, frequency. In order to analyze the When high-power laser is focused in water through an optical focusing lens system, the water is broken down and high-power acoustic wave is emitted. The different optical focusing lens system relates to different acoustic waveform characteristic, such as the sound pressure intensity, frequency. In order to analyze the relation between the pressure signal and optical focusing characteristic, we simulate the dynamic process of the laser-induced cavitation bubble model and the laser-induced acoustic signal model. The experimental investigation is done. The laser-induced pressure acoustic signal is detected with the high-frequency transducer. The laser-induced cavitation bubble expansion and collapse is recorded with high-speed video. The shock wave and cavitation bubble begin after optical breakdown in water. The laser-induced bubble radius and power acoustic density make a linear relation with the laser energy directly. For high-power laser, compared with the unexpanded beam, the bumble radius is larger and the acoustic signal is more intense for the expanded beam. To increase the opto-acoustic efficiency, the laser beam should be expanded and focused..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1384 (2009)
Quantum Optics
Effect of Wetting Layer Transition and Pure Dephasing on Rabi Oscillation Decoherence in Semiconductor Quantum Dots
Liu Wenjuan, Liu Shaoding, Li Jianbo, and Hao Zhonghua
The effect of wetting layer transition, including leakage and Auger capture processes, on Rabi oscillation decoherence process in semiconductor quantum dots is analyzed theoretically. The population dynamic equations of a quantum dot interacting with the wetting layer are deduced, and they fit well with the experimentaThe effect of wetting layer transition, including leakage and Auger capture processes, on Rabi oscillation decoherence process in semiconductor quantum dots is analyzed theoretically. The population dynamic equations of a quantum dot interacting with the wetting layer are deduced, and they fit well with the experimental result. The effect of pure dephasing on Rabi osciuation decoherence process is comparatively analyzed. The calculation results show that the simple intensity-dependent damping factor of pure dephasing can well describe the decoherence properties of complex multi-level system..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1391 (2009)
Remote Sensing and Sensors
Research on Sub-Telescopes′ Beams Parallel and Path Difference Adjustment to the Optical Aperture Synthesis Telescope
Wang Haitao, Zhu Yongkai, Cai Jiahui, Zhang Yajing, and Tian Guiyun
It is an effective way combining optical interference technology with astronomical telescope technology to raise the astronomical observation resolution. We use a telescope array to replace the large-diameter telescope for light-gathering observation. The maximum baseline is equivalent to the largest diameter of traditIt is an effective way combining optical interference technology with astronomical telescope technology to raise the astronomical observation resolution. We use a telescope array to replace the large-diameter telescope for light-gathering observation. The maximum baseline is equivalent to the largest diameter of traditional optical telescope. To a great extent, it solves the problem of single telescope, whose light-gathering ability is not sufficient and angular resolution is not so high. In practice, only if the requirements below are fulfilled can the two beams be partly coherent: the phase difference must be relatively stabilized; it exists the component of mutual parallel oscillation; it has the same frequency; the oscillation amplitude difference of the two beams which vibrate at the meeting point is not so large and the optical path difference (OPD) of the two beams at the meeting point is less than the coherent length and so on. The sub-telescope should be mutual interference. Two parallel beams interference and OPD requirement formula are deduced. We get the requirement of the two parallel beams and the OPD based on the research on the two-beam parallel requirement and the OPD. Two indexes for the OAS telescope sub-telescope beam parallel and OPD are got combined with the OAS telescope character. The method of two beams interference parallel and OPD adjustment is introduced. The adjustment method for parallel and OPD optical system is researched which fits with the OAS telescope. The improvement for the system is discussed in the end..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1397 (2009)
Remote Sensing Quantitative Monitoring and Analysis of Fuel Moisture Content Based on Spectral Index
Li Yuxia, Yang Wunian, Tong Ling, Jian Ji, and Gu Xingfa
Some bands or band combination are used as the spectral indices of fuel moisture content based on analyzing the spectral characteristic and relation of spectrum and fuel moisture content. The optimal function models are respectively established between the fuel moisture content and spectral indices. By analyzing the spSome bands or band combination are used as the spectral indices of fuel moisture content based on analyzing the spectral characteristic and relation of spectrum and fuel moisture content. The optimal function models are respectively established between the fuel moisture content and spectral indices. By analyzing the spectral index and its relative error, it confirms the spectral index SR=R1600/R820 as the characteristic parameters of the model, where R1600 and R820 are the reflectivities at 1600 nm and 820 nm. Utilizing the measured vegetation spectral reflectance and fuel moisture content, the model relation between fuel moisture content and SR spectral index is established. According to the model of fuel moisture content, ETM and ASTER remote sensing data, the quantitative inversion are achieved by the programme based on IDL7.0 platform. The measured data and background data surveyed in the study area are used to evaluate and analyze the inversion results synthetically. The results show that the spectral index SR can eliminate the outside impact of the background environment, the canopy structure, and other factors. The remote sensing retrieval precision of fuel moisture content superior. It can reflect the variety characteristics of the fuel moisture content in the study area veritably..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1403 (2009)
Synthetic Aperture Imaging Ladar(V): Imaging Resolution and Antenna Aperture Function
Liu Liren
The azimuth imaging resolution of synthetic aperture imaging ladar (SAIL) using the telescopes with circular and rectangular apertures is investigated based on the point target SAIL data collection equation, and the analytic expressions of point spread function for imaging are correspondingly achieved. The ideal resoluThe azimuth imaging resolution of synthetic aperture imaging ladar (SAIL) using the telescopes with circular and rectangular apertures is investigated based on the point target SAIL data collection equation, and the analytic expressions of point spread function for imaging are correspondingly achieved. The ideal resolution spot and its degradation due to the target deviation vertically from the footprint center, the mismatch of matched filtering from the quadratic phase history, and the limited width and period for sampling are discussed. And the deficient compensation of phase errors of nonlinear chirping and the others related to range resolution are also detailed. Mathematical criteria are derived for all of these factors. Moreover, an explanation to the resulted azimuth resolution from the earlier experiment in our laboratory-scaled SAIL is given to verify the developed theory. As a conclusion, it is found that the antenna of rectangular aperture telescope can provide a rectangular footprint more suitable for the SAIL scanning format, and this leads not only to an elimination of resolution degradation but also to an optimal design of aperture to give both a fine resolution and a wide scan strip. And it is also found that the delay between the target and the local oscillator must be small enough to eliminate the phase errors from nonlinear chirping and optical frequency instability..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1408 (2009)
Spectroscopy
Study of Spectral Reconstruction Based on Digital Camera
Chen Yiyi, Xu Haisong, Zhang Xiandou, and M. Ronnier Luo
Directly recovering the spectral information of surface colors using digital camera signals is important for color reproduction under various illuminating conditions. The RGB signals for color samples were obtained by a commercial digital camera under two different CIE illuminants, D65 and A, to reconstruct their correDirectly recovering the spectral information of surface colors using digital camera signals is important for color reproduction under various illuminating conditions. The RGB signals for color samples were obtained by a commercial digital camera under two different CIE illuminants, D65 and A, to reconstruct their corresponding spectral reflectance based on the algorithm combining principal component analysis(PCA) and polynomial model. The experimental results indicate that the spectral reconstruction accuracy could be improved by simultaneously utilizing the RGB signals under the two illuminants, in which case the metameric characteristics of color pairs could also be well reproduced..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1416 (2009)
Spectral Characteristics of a New Iridium(Ⅲ) Organic Complex
Sun Xiaochen, Zhu Tuo, Chen Guoqing, and Ding Yuqiang
A new phosphorescent (pq)2Ir(N-phenyl-isobutyramide) complex is synthesized and its spectral characteristics are investigated. The ligands of this complex are phenyl-quinoline and N-phenyl-isobutyramide. The complex is characterized by UV-Vis absorption spectrometry and luminescence spectrometry, and the results show tA new phosphorescent (pq)2Ir(N-phenyl-isobutyramide) complex is synthesized and its spectral characteristics are investigated. The ligands of this complex are phenyl-quinoline and N-phenyl-isobutyramide. The complex is characterized by UV-Vis absorption spectrometry and luminescence spectrometry, and the results show that strong absorption appeared at about 225 nm, 267 nm, 339 nm and 460 nm, respectively. Especially the complex shows single and triplet metal-to-ligand charge transfer from 320 nm to 580 nm. The luminescence spectra indicate that the increase in concentration of the iridium (Ⅲ) organic complex in the solution with the solvent of CH2Cl2 leads to red shift of luminescence spectra. At the excitation wavelength of 460 nm, the luminescence interference of dichloromethane is absent, so the strong metal triplet phosphorescence at around 606 nm of the Ir(Ⅲ) organic complex was generated by itself. Therefore, we conclude that the Ir(Ⅲ) organic complex can be used as a new phosphorescent material for the application in organic electroluminescence area..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1420 (2009)
Thin Films
Fabrication of All-Inorganic Smart Window Device by Cooling Substrate with Liquid Nitrogen and Study on Its Performance
Wang Huaiyi, Diao Xungang, Wang Wuyu, Yang Haigang, Hao Weichang, Wang Cong, and Wang Tianmin
In order to slow down the increase of substrate temperature during sputtering and then obtain electrochromic films with amorphous-porous or nano-microcrystalline structures and ion conductive film with amorphous state, a cooling facility based on liquid nitrogen, with magnetron sputtering installation has been proposedIn order to slow down the increase of substrate temperature during sputtering and then obtain electrochromic films with amorphous-porous or nano-microcrystalline structures and ion conductive film with amorphous state, a cooling facility based on liquid nitrogen, with magnetron sputtering installation has been proposed. By using the facility, a single-substrate all-inorganic electrochromic smart window device consisting of WO3,NiOx, and LiNbO3 films is prepared. Its electrochromic performance has been measured by spectrophotometer, and transmittance averages of its bleached and colored states in range of 400～800 nm wavelengths have been calculated. Experimental results reveal that after 50 cycles, transmittance averages of bleached and colored states of the device have reached 61.5% and 5.5%,respectively. X-ray diffraction and SEM images show that the structures of the WO3, NiOx, and LiNbO3 films are amorphous-porous, nano-microcrystalline, and amorphous states,respectively..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1424 (2009)
Vision, Color, and Visual Optics
Study on Just-Noticeable Color Difference Discrimination Threshold by Using Printed Samples I: Analysis of Visual Evaluation Experimental Data
Huang Min, Liu Haoxue, and Liao Ningfang
In order to study the human color vision characteristics, the just-noticeable color difference discrimination threshold experiment at the 17 basic CIE color centers with about 1000 pairs of samples was carried out by 16 observers with normal color vision on the CIE1976 a*-b* plane, by using reflective samples color stiIn order to study the human color vision characteristics, the just-noticeable color difference discrimination threshold experiment at the 17 basic CIE color centers with about 1000 pairs of samples was carried out by 16 observers with normal color vision on the CIE1976 a*-b* plane, by using reflective samples color stimuli based on the psychophysical method of constant stimuli. And the color discrimination thresholds were represented via chromaticity ellipses. The detailed processing and analysis of the experimental results indicate that the color discrimination characteristics of human eyes are different for individual color regions and directions in the a*-b* plane,and namely the CIE1976 a*-b* plane is visually non-uniform. The visual color tolerance in the third and fourth quadrants is smaller than the first and second quadrants, the biggest tolerance is in the region of high chroma orange, and the smallest is in blue.The visual color difference scale in the red-green direction is generally smaller than that in the yellow-blue one for the 17 CIE color centers. The experimental data provides references for the improvement of uniform color space and color-difference formula..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 5, 1431 (2009)
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