Journals >Acta Photonica Sinica
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2014
Volume: 43 Issue 1
30 Article(s)
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Research Article
Propagation of Partially Coherent Bessel-Gaussian Beams in Non-Kolmogorov Turbulence
JIANG Yue-song, ZHANG Xin-gang, WANG Shuai-hui, OU Jun, and TANG Hua
Based on the extended Huygens-Fresnel principle, analytical expressions for the average intensity and degree of polarization of partially coherent Bessel-Gaussian beams propagating in non-Kolmogorov turbulence were devived. The intensity distribution feature and the variation pricinple of polarization degree were studiBased on the extended Huygens-Fresnel principle, analytical expressions for the average intensity and degree of polarization of partially coherent Bessel-Gaussian beams propagating in non-Kolmogorov turbulence were devived. The intensity distribution feature and the variation pricinple of polarization degree were studied, and the effects of the exponent parameter, structure constant, outer scale, inner scale, topological change and coherent length on the propagation properties were analyzed. The results show that the beam profile approaches to a Gaussian shape from a hollow shape and gets some spreads with increasing the value of the propagation distance. The average intensity distribution changes more quickly and gets more spreads with exponent parameter closer to 3.1, larger structure constant, larger outer scale and smaller inner scale.When the topological charge or coherent length is smaller, the average intensity distribution changes faster, but it has few effects on the spread phenomenon. Furthermore, at near distance the degree of polarization first fluctuates, then a rise and a reduce appear in succession, and when the propagation distance is long enough it tends to a stable value which equals the initial value on the source plane. The variation process is affected by the exponent parameter, structure constant, outer scale, inner scale, topological charge and coherent length..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 101001 (2014)
System Research and Simulation of New Type Dual-channel Mach-Zehnder Frequency Discriminator for Doppler Lidar Wind Measurement
WANG Li, TAN Lin-qiu, XING Mei-li, DI Hui-ge, WANG Yu-feng, and HUA Deng-xin
Mach-Zehnder (M-Z) interferometer can be used in Doppler lidar for wind measurement as frequency discriminator. The common M-Z interferometer′s stability is poor and not easy to adjust. A new type dual-channel M-Z interferometer was proposed as frequency discriminator based on dual prism. Through analyzing the wind meaMach-Zehnder (M-Z) interferometer can be used in Doppler lidar for wind measurement as frequency discriminator. The common M-Z interferometer′s stability is poor and not easy to adjust. A new type dual-channel M-Z interferometer was proposed as frequency discriminator based on dual prism. Through analyzing the wind measurement theory, the system was optimized and designed with optical design software. The wind velocity was retrieved from simulation result through setting experiment parameter. Compared with the theoretical wind velocity calculated from Doppler frequency shift formula, the result indicates that the retrieval simulation wind velocity agrees with theoretical wind velocity; the standard deviation is 0.46 m/s. So the new type structure can be applied in Doppler wind lidar as frequency discriminator. The optical path is easy to adjust and the system stability is improved..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 101002 (2014)
Simultaneous Determination of Aerosol Optical Thickness and Exponent of Junge Power Law over East China Sea Based on MODIS Data
BIAN Jian, CAO Ya-nan, XU Meng-chun, and XU Qing-shan
Based on the reflectance data of the fifteenth and sixteenth channels in near-infrared bands and spatial geometrical angles of the moderate resolution imaging spectro-radiometer, a physical iterative algorithm was proposed, using the Junge power-law size distribution to approximate the actual atmospheric aerosol model.Based on the reflectance data of the fifteenth and sixteenth channels in near-infrared bands and spatial geometrical angles of the moderate resolution imaging spectro-radiometer, a physical iterative algorithm was proposed, using the Junge power-law size distribution to approximate the actual atmospheric aerosol model. The algorithm was used for simultaneous determination of the aerosol optical thickness and the exponent of the Jung power law. The results show that the aerosol optical thickness over most of the studied ocean is in the range of 0.02~0.17, the exponent of the Jung power law is in the range of 2.8~3.8, and both the aerosol optical thickness and exponent of the Jung power law have the trend of descending from coast to open sea. Therefore, the reasonable spatial distributions of the exponent of the Junge power law and aerosol optical thickness were obtained. Comparing the retrieval results with the moderate resolution imaging spectro-radiometer product and aerosol robotic network measurements, the retrieval algorithm whose results are more approach aerosd robotic network data than moderate resolution imaging spectro-radiometer product, is more accurate than moderate resolution imaging spectro-radiometer algorithm. Therefore, the retrieval method which is applied for the studied region is feasible and reliable..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 101003 (2014)
Dynamic Characteristics of Forward Light Scattering by Simulated Bubble Film based on CMOS
ZHANG Jian-sheng, SUN Jian-peng, CHEN Yan, LI Xu-dong, and LIU Hua-cheng
The concepst of Vertical-plane and Horizontal-plane scattering angle of forward laser paraxial were proposed based on CMOS. The dynamic image sequence of light scattering by simulated bubble film, which was captured by CMOS, can be expressed by an image sequence matrix whose line vector and column vector represented onThe concepst of Vertical-plane and Horizontal-plane scattering angle of forward laser paraxial were proposed based on CMOS. The dynamic image sequence of light scattering by simulated bubble film, which was captured by CMOS, can be expressed by an image sequence matrix whose line vector and column vector represented one frame image through computing gray average of column pixel and line pixel of the frame image. The gray distribution and evolution characteristics of 100 frame image sequence of forward light scattering by bubble film generated under presser 0.005 and 0.01 MPa, was analyzed qualitatively through calculating the mean horizontal and vertical gray, as the dynamic range and correlation of 5 frame image was analyzed quantitatively. Through analyzed the dynamic image scattered by bubble film with the increasing pressure on CMOS, the range and amplitude of horizontal and vertical gray of forward light scattering image sequence increased as the increasing scale, number density and rising speed of bubble film..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 101004 (2014)
New Cloud Droplet Probe and Its First Observation Results
BU Ling-bing, GAO Ai-zhen, YUAN Jing, GAO Hai-yang, and HUANG Xing-you
Cloud droplet probe plays an important role in activities of weather modification for its high efficiency and simple structure. In this paper, a new cloud droplet probe in which a single-mode 685 nm laser with fiber output coupling was used as a transmitter. A pinhole was used to cut the beam of the laser, so only the Cloud droplet probe plays an important role in activities of weather modification for its high efficiency and simple structure. In this paper, a new cloud droplet probe in which a single-mode 685 nm laser with fiber output coupling was used as a transmitter. A pinhole was used to cut the beam of the laser, so only the central part of the beam which was relatively homogenous illuminated cloud droplets. An embedded computer with two high speed A/D convert chips (10M/s) was used to acquire and process the signal from cloud droplets continually. All the raw data from cloud droplets was stored on the solid disk of embedded computer as well as the calculated size distribution was sent to the master computer in the carbin. By the calibration using standard particles with known index and sizes, the response curve of probe was obtained from which the magnitudes of cloud signal can be changed into sizes of droplets. In the end, the probe was installed on an airplane and field observation experiments were conducted. The results show that this probe is able to measure cloud droplets..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 101005 (2014)
Design and Experiment of Pocket Infrared Gas Detecter
YU Xin, GAO Zong-li, SONG Nan, LIU Yang, ZHENG Chuan-tao, and WANG Yi-ding
On the base of meeting requirements of gas detection, a low-cost, low-power, low limit of detection, high SNR(signal to noise ratio) pocket methane detector was designed, with the improvement on the original gas absorption theory, and the core sensing module contains a mid-infrared light source, optical path, a mid-infOn the base of meeting requirements of gas detection, a low-cost, low-power, low limit of detection, high SNR(signal to noise ratio) pocket methane detector was designed, with the improvement on the original gas absorption theory, and the core sensing module contains a mid-infrared light source, optical path, a mid-infrared dual detector. The device adopted dry batteries single power supply, and totally the supply current was less than 150 mA while the power consumption was less than 0.9 W, and the gain of the circuit was 43.3 dB. The single and dual channel detection experiments were carried out to contrast, and with the novel proportioning gas method both the sensitivity and the minimum detection limit under low concentration range could reach to 50 parts per million. Compared with the pre-existing wall-mounted devices, this device satisfies the requirement of detecting explosive gases in a more convenient handheld style..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 104001 (2014)
Anode Sulphur Passivation of InAs/GaSb Superlattice Infrared Photodiodes
GUO Jie, HAO Rui-ting, DUAN Jian-jin, XU Lin, and LI Yin-zhu
InAs(8ML)/GaSb(8ML) superlattice with p-i-n structure was grown on GaSb substrates by molecular beam epitaxy. The mid-wavelength infrared photodiodes with different area mesa was fabricated through standard photolithography, wet chemical etching and sputtered metal contacts. The passivation was finished by the anode suInAs(8ML)/GaSb(8ML) superlattice with p-i-n structure was grown on GaSb substrates by molecular beam epitaxy. The mid-wavelength infrared photodiodes with different area mesa was fabricated through standard photolithography, wet chemical etching and sputtered metal contacts. The passivation was finished by the anode sulphur technique and sputtered ZnS thin film. Compared with (NH4)2S solution treatment, the surface leackage currents density decreased three orders of magnitude and the R0A increased up to 103 times. The zero-bias resistance R0 was measured up to 106 ohms. The surface leakage current was not major dark current in photodiodes after the anode sulfur passivation. Capacitance-voltage relation showed that the background concentration in i layer was about 4~5×1014 cm－3. The property of the photodiode appeared no degradation after exposured in air for one month. It verified that anode sulphur passivation is an easy and effective technique..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 104002 (2014)
Study on Electro-optical Diffraction Characteristics of Periodically Poled Lithium Niobate Based on the Rigorous Coupled Wave Theory
WAN Ling-yu, LU Zhi-yong, LIAO Yang, CHAO Liang-fang, and HU long-gan
Using the rigorous coupled wave theory, the electro-optical diffraction properties of periodically poled lithium niobate with different parameters were numerically studied. The analysis show that, the periodic domain structures of a periodically poled lithium niobate act as an index of refraction diffraction grating unUsing the rigorous coupled wave theory, the electro-optical diffraction properties of periodically poled lithium niobate with different parameters were numerically studied. The analysis show that, the periodic domain structures of a periodically poled lithium niobate act as an index of refraction diffraction grating under the applied electric fields and its diffraction characters have relation to the geometry structures, the period, the applied electric-fields and the incident angles. The periodically poled lithium niobate produces Bragg diffraction under the Bragg condition. In this case, the 0 order of diffraction light is periodically converted to －1 order of diffraction light with the increase of applying electric field. The maximum conversion efficiency can reach to 100% and the conversion voltage value can be reduced effectively by lengthening crystal. If angle of incidence is the Bragg angle, and the propagation of light in periodically poled lithium niobate does not satisfy the conditions of Bragg diffraction, the power of 0 order diffraction light can not transfer to －1 order of diffraction light with 100%. Meanwhile, the periodic modulation are damaged. The 0 order light is converted to corresponding multiple orders of diffraction lights with high diffraction efficiency when the incident angles are multiple Bragg angles. The maximum conversion efficiency is also reach 100%. The analysis results are helpful for developing the integrated devices of periodically poled lithium niobate..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 105001 (2014)
Design of High-efficiency Full Polarization Blazed Gratings with Rectangular Groove
ZHAO Hua-jun, WU Qiang, and REN Xiao-xia
A plan wave incident upon the grating will excite discrete modes. The modes with n2eff>0 can propagate through the gratings, while those with n2eff<0 are evanescent modes. The basic idea behind the simplified modal investigation is the excitation and coupling of the propagating modes in gratings. If an odd numberA plan wave incident upon the grating will excite discrete modes. The modes with n2eff>0 can propagate through the gratings, while those with n2eff<0 are evanescent modes. The basic idea behind the simplified modal investigation is the excitation and coupling of the propagating modes in gratings. If an odd number multiple phase difference is accumulated for the first two propagating modes, the incident light will be diffracted into the －1st order with nearly 100 % diffraction efficiency. A highly efficient full polarization blazed grating with rectangular groove was designed theoretically by modal method in the resonance domain. The design procedure of the full polarization rectangular blazed grating could be divided into three steps. Step 1: present the grating period in the resonance domain. Step 2: present fill factor by the eigenvalue functions of the grating. Step 3: present groove depth based on the phase difference of the propagating modes. As an example, the design of the fused silica full polarization rectangular blazed grating was demonstrated for the wavelength of 633 nm, which has about 96.7% and 98.1% negative first-order diffraction efficiency for TE and TM polarizations, respectively. The full polarization blazed grating with fused silica has a wide-band incident angles and incident wavelengths, which especially has high fabrication tolerances..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 105002 (2014)
Effects of Amplitude Ratio on Composite Stokes Singularities in Coherently and Incoherently Superimposed Vector Optical Beams
BAI Wen-hai, HE De, and GAO Zeng-hui
Based on the Stokes parameters, the complex Stokes scalar fields and the Fresnel diffraction integral method, the expressions for the composite Stokes singularities versus amplitude ratio η in two coherently and incoherently superimposed paraxial monochromatic vector optical beams were derived. The properties of composBased on the Stokes parameters, the complex Stokes scalar fields and the Fresnel diffraction integral method, the expressions for the composite Stokes singularities versus amplitude ratio η in two coherently and incoherently superimposed paraxial monochromatic vector optical beams were derived. The properties of composite Stokes singularities in coherently and incoherently superimposed vector optical beams with amplitude ratio propagating in free space were investigated, and the degree of polarization versus the amplitude ratio is analyzed. It is found that, during propagating in free space, the number, position and singularity index of composite Stokes singularities are affected by the amplitude ratio of two vector beams. In the coherent superposition the degree of polarization P=1. At the z=0 plane, when the amplitude ratio η≠1, singularity indices of C-points, S23 and S31 singularities may be reversed. The creation of S23 singularity with double singularity index may take place at the z>0 plane. In the incoherent superposition, the degree of polarization P is less than 1 and is variable with η, by varying the amplitude ratio η V-points may appear, which are unstable and split up into S23 singularities and C-points with handedness reversal. With a further increase of ηS23 singularities may annihilate. In addition， the sum of singularity indices of composite Stokes singularities is conserved in the process..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 105003 (2014)
Detection of Moving Objects in Dynamic Scenes Based on Robust M-estimator and Mean Shift Clustering
XU Cheng, and HUANG Da-qing
Focusing on the problem of moving objects detection in dynamic scenes, a novel algorithm based on robust M-estimator and mean shift clustering was proposed. First, considering the case of global illumination change, M-estimator was constructed to estimate the global motion in order to minimize the absolute residuals ofFocusing on the problem of moving objects detection in dynamic scenes, a novel algorithm based on robust M-estimator and mean shift clustering was proposed. First, considering the case of global illumination change, M-estimator was constructed to estimate the global motion in order to minimize the absolute residuals of pixels luminance between two adjacent frames. The structured outliers could be extracted according to the weight map of every pixel. Then the grid points were selected evenly from outliers and different point belong different moving object was clustered by mean shift algorithm. The convex hulls were generated under clustering results, to accurately segment the moving object regions. Experimental results show that this method can accurately detect multiple moving objects in dynamic scenes, and MODA can reach 95%. Besides, only two frames are needed to detect and lock the moving objects by this algorithm, which can meet real-time processing requirements and has a certain degree of engineering significance..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 110001 (2014)
Improved Non-uniformity Correction Algorithm Based on Integration Time Calibration for IRFPA
LENG Han-bing, ZHOU Zuo-feng, YI Bo, ZHANG Jian, YAN A-qi, WANG Hao, and CAO Jian-zhong
The infrared image quality and temperature resolution is degraded significantly by the non-uniformity response of infrared focal pattern array. Calibration-based and scene-based non-uniformity correction algorithms provide feasible way to handle this problem. Due to its simplicity and accuracy, traditional blackbody caThe infrared image quality and temperature resolution is degraded significantly by the non-uniformity response of infrared focal pattern array. Calibration-based and scene-based non-uniformity correction algorithms provide feasible way to handle this problem. Due to its simplicity and accuracy, traditional blackbody calibration-based non-uniformity correction method is widely used but with the disadvantage of highly dependence on the existence of blackbody and its temperature control equipment to provide uniform irradiances. In this paper, an improved two-level non-uniformity correction algorithm based on integration time calibration was proposed. Given the irradiance, the different response data is first obtained through integration time variation. Then the least square method is used to estimate the initial gain coefficients and bias coefficients for two point correction algorithm. Finally, the one point correction coefficients are estimated throuth two point correction of different response data. Experimental results show that the proposed algorithm has the merits of low complexity, high precision, excellent non-uniformity correction performance, and can easily be integrated into hardware platform..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 110002 (2014)
Temporal High-pass Filter Nonuniformity Correction Algorithm Based on Non-local Means Filter for Infrared Focal Plane Array
ZHANG Shuang, ZHOU Hui-xin, NIU Xiao-xue, QIN Han-lin, and QIAN Kun
The nonuniformity correction algorithm with the temporal high-pass filter for infrared focal plane array is a typical scene-based nonuniformity correction technique, but it has the ghosting artifacts problem. Based on the basic principle of temporal high-pass filter algorithm, the superposition of the whole image inforThe nonuniformity correction algorithm with the temporal high-pass filter for infrared focal plane array is a typical scene-based nonuniformity correction technique, but it has the ghosting artifacts problem. Based on the basic principle of temporal high-pass filter algorithm, the superposition of the whole image information will result in the elimination of stationary scene and the stay of a reversed image which can be referred to as the ghosting artifacts on the current position of the moving scene. A new scene-based nonuniformity correction technique based on the non-local means filter was proposed to eliminate the ghosting artifacts in the temporal high-pass filter algorithm. In this algorithm, the original input image was separated into two parts, which were the high spatial-frequency part and the low spatial-frequency part. And then the output of the low-pass filter was estimated recursively only by using the high spatial-frequency part of the image which contains most of the noise and nonuniformity. The performance of this presented algorithm was tested with two infrared image sequences, and the experimental results show that the algorithm can significantly reduce the ghosting artifacts in THF and achieve a better nonuniformity correction effect..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 110003 (2014)
Hand Vein Recognition Based on Feature Fusion
HU Yun-peng, WANG Zhi-yong, LI Fei, YANG Xiao-ping, and XUE Yu-ming
Image translation and rotation reduces the accuracy of hand vein recognition. Aiming at this problem, a new hand vein recognition algorithm was proposed based on multi-feature fusion. The characteristic of the approach was to combine local and global features for hand vein recognition. Firstly, intersection points and Image translation and rotation reduces the accuracy of hand vein recognition. Aiming at this problem, a new hand vein recognition algorithm was proposed based on multi-feature fusion. The characteristic of the approach was to combine local and global features for hand vein recognition. Firstly, intersection points and endpoints were selected as feature points. The reference point for image matching was extracted from feature points. The relative distances between the reference points to feature points were computed. The angles between the adjacent connections were calculated and used as local features. Then the moment invariants were calculated as global features. Finally these features were combined for hand vein recognition. Experimental results show that the proposed algorithm is able to achieve hand vein recognition reliably and quickly..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 110004 (2014)
A Distortion Field-calibrating Method Based on Feature Parallel Lines of Image
WANG Gui-ping, WANG Hui-feng, LIU Pan-zhi, and JU Yong-feng
Considering the effect on the image measurement system, a distortion calibration method was designed after analyzing the model of lens distortion. The method consists of two steps, namely calibration on the non-linear distortion and calibration on the perspective distortion. In the first step, the non-linear distortionConsidering the effect on the image measurement system, a distortion calibration method was designed after analyzing the model of lens distortion. The method consists of two steps, namely calibration on the non-linear distortion and calibration on the perspective distortion. In the first step, the non-linear distortion coefficients of the lens were obtained form drawing the multi feature straight lines and straightening the feature lines. With these coefficients, the non-linear of the image was calibrated, and an image without any non-linear distortion was achieved. In the second step, the distortion parameters were obtained through fitting the parallel-line feature of the image. With these parameters, the perspective distortion was calibrated, and an image without perspective was achieved.The experiments and simulations show that the radial and the perspective-distortion relatively error can be reduced to 5% with this method, which can be used in many similar engineering systems based on image measurement and target recognition in non-fixed locations..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 111001 (2014)
Three-channel Polarization Imaging Systems and System Error Correction Method
JI Er-you, GU Guo-hua, BAI Lian-fa, and QIAN Wei-xian
The existing polarization imaging systems are hard to meet the requirements of target detection and tracking in real-time image processing field. A three-channel polarization imaging system was put forward to solve above problems, and correction methods were proposed to solve the field differences and non-uniformity erThe existing polarization imaging systems are hard to meet the requirements of target detection and tracking in real-time image processing field. A three-channel polarization imaging system was put forward to solve above problems, and correction methods were proposed to solve the field differences and non-uniformity errors of the three-channel polarization imaging system. This system used three separate channels to acquire the polarization images from the direction of 0°, 60° and 120°. SIFT algorithm was used to solve the field differences among three independent channels. According to depolarization characteristics of the integrating sphere and linear response model of the detector, integrating sphere was used to produce unpolarized light to correcte the non-uniformity errors. Experimental results show that: 1) the imaging effect of the corrected three-channel polarization imaging system can be close to the level of single-polarization imaging system′s; 2) the system can capture images real-time meanwhile overcome the quality-descent problem of the polarization images caused by multi-channel, improving the practical applicability..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 111002 (2014)
Design of Tripleband Optical Imaging System and Analysis of Ghost Image
GUO Bang-hui, WANG Jian, HUANG Jian-bo, and SUN Qiang
In order to measure multiband radiation characteristic of objects, a tripleband optical imaging system working in 300～1 000 nm range was designed, which shared the same optical window. In this system, two right-angle prisms were used to split light of different waves, and each band used independent optical lens. This sIn order to measure multiband radiation characteristic of objects, a tripleband optical imaging system working in 300～1 000 nm range was designed, which shared the same optical window. In this system, two right-angle prisms were used to split light of different waves, and each band used independent optical lens. This system can obtain images at the same time in the wavebands of ultraviolet, visible and infrared. The ghost image of the system was simulated and analyzed with the help of Lighttools software. It is shown that there are multiple ghost images which reduce the contrast ratio of the images on the surface of detector, because of light multiple reflected between the surfaces of right-angle prism and window. Experimental results show that the tripleband optical imaging system can achieve good image quality, and the ghost images can be cleared away when the angle of the optical window and the first prism is controlled in seven seconds. The efforts of this paper are referable for research and design of multiband optical imaging system using prism to split light..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 111003 (2014)
Calibration Algorithm of Underwater Imaging System Based on PSO
ZHANG Qiang, WANG Xin, and LI Hai-bin
Light refraction occurs when imaging in the water, and the pin-hole imaging model is no longer valid. Calibration methods existing can′t calibrate the system parameters correctly. This paper presents an underwater calibration algorithm based on particle swarm optimization. Firstly, Zhang′s calibration method is employeLight refraction occurs when imaging in the water, and the pin-hole imaging model is no longer valid. Calibration methods existing can′t calibrate the system parameters correctly. This paper presents an underwater calibration algorithm based on particle swarm optimization. Firstly, Zhang′s calibration method is employed to calculate intrinsic parameters and external parameters of the two cameras in the air. The evaluation function is accomplished via length measurement, and then the distance from optical center to refractive interface d, the normal vector nπ and the thickness of waterproof cover h are calibrated by using particle swarm optimization. Trough experimental comparison, the relative positioning errors are 3.29% and 2.68% in the method of high order distortion compensate refraction, while those are 1.99% and 0.62% in the proposed algorithm. Compared with previous method, the proposed algorithm can calibrate parameters accurately and decrease the relative positioning errors obviously, which is important to positioning research in submerged circumstance..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 111004 (2014)
Effects of Different Thicknesses of Modified Cathode Material LiF on the Performance of Poly(2-methoxy,5-octoxy)-1, 4-phenylenevinylene-SWNT-PbSe Composite Solar Cells
ZHENG Jian-banga, WU Guang-ronga, QU Jun-ronga, HUANG Xing-yangb, and CAO Chong-dea
Single-walled carbon nanotubes have characteristics of good conductivity, baryon transmission performance, and high photoelectric conversion performance of quantum dot composite material. In situ condensation method was used to prepare polymer/poly(2-methoxy, 5-octoxy)-1, 4-phenylenevinylene-single walled carbon nanotuSingle-walled carbon nanotubes have characteristics of good conductivity, baryon transmission performance, and high photoelectric conversion performance of quantum dot composite material. In situ condensation method was used to prepare polymer/poly(2-methoxy, 5-octoxy)-1, 4-phenylenevinylene-single walled carbon nanotubes-PbSe quantum dot composites. X-ray diffraction, transmission electron microscope, UV-vis absorption spectroscopy were applied to study their characteristics. The results indicate: poly(2-methoxy, 5-octoxy)-1, 4-phenylenevinylene, single walled carbon nanotubes and PbSe quantum dots can be effectively combined, especially the single walled carbon nanotubes and poly(2-methoxy, 5-octoxy)-1, 4-phenylenevinylene form a network structure in poly(2-methoxy, 5-octoxy)-1, 4-phenylenevinylene matrix; PbSe quantum dots, each with an average size of 5.75 nm, can be dispersed to form a coating or mosaic structure in the polymer substrate of poly(2-methoxy, 5-octoxy)-1, 4-phenylenevinylene -single walled carbon nanotubes, producing the light induced charge transfer phenomenon. The study of composite photoelectric performance shows that inserting different thicknesses of modification cathode material LiF, improving the photoelectric performance of the composite, and when the thickness of LiF is 3 nm, open circuit voltage is 0.558 V, short circuit current is 2.338 mA, fill factor is 37.6%, conversion efficiency is 0.466%. Compared with that without LiF, the optoelectronic properties increased 30%..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 116001 (2014)
Enhancing Electric Field with Gold Subwavelength Slits and Nanowires
SONG Chao, HAO Peng, YU Mu-xin, ZHOU Wen-chao, CHEN Si-wei, and WU Yi-hui
In order to strengthen the electric field between two gold nanowires, a kind of structure was designed by putting them into periodical subwavelength slits. This structure combined the effect of amplifying electric field from the near-field coupled effect and the quasi-Fabry-Perot resonance. Theoretical study indicated In order to strengthen the electric field between two gold nanowires, a kind of structure was designed by putting them into periodical subwavelength slits. This structure combined the effect of amplifying electric field from the near-field coupled effect and the quasi-Fabry-Perot resonance. Theoretical study indicated that the electric field between gold nanowires showed periodical variation when depth of slits changes, and the peak of electric field appeared when Quasi-Fabry-Perot resonance happened, and nanowires were able to modulate the depth of resonance. The electric field turned out a sharp peak when the period was approaching to the wavelength of incident light, and it decreased rapidly as the interval of wires increased. According to the result calculated by finite element method, enhancing effect is considerable when the interval varies from 1 nm to 2 nm. It gets a 200 electric field enhancement which means a 109 Raman enhanced factor in hot spot between the two gold nanowires in subwavelength slits by reasonably adjusting the period and depth of the slits, which is three orders of magnitude than two lonely wires..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 116001 (2014)
Systematic Study of Finite-difference Frequency-domain Method for Spontaneous Emission in a Two-dimensional Environment
QI Jian-nan, HUANG Zhi-xiang, WANG Han-lin, WU Xian-liang, CHU Jing-yang, and ZHOU Li
The improvement of the efficiency of spontaneous emission will give great help to the research and manufacture of optoelectronic devices such as single photon resource. The local density of elestromagnetic states was calculated which is represented by the electric dyadic Green′s function through the finite-difference fThe improvement of the efficiency of spontaneous emission will give great help to the research and manufacture of optoelectronic devices such as single photon resource. The local density of elestromagnetic states was calculated which is represented by the electric dyadic Green′s function through the finite-difference frequency-domain method, the local density of states and the spontaneous emission rate in different metal materials, structures and wavelengths were analyzed, and the intrinsic physical mechanism was explored. The results show that the spontaneous emission rate of atoms can be greatly enhanced when surface plasmon polariton couple to the emiter, and different structure and the refractive indices of materials have different improvement of spontaneous emission rate. This research can provide important reference for the manufacture and optimization of optoelectronic devices..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 116002 (2014)
Dehydration Processing in Nd3+-doped Phosphate Laser Glass
CAO Liang-jun, YU Tian-lai, QIU Hong, MO Da-hong, and WANG Zhao-ning
Nd3+-doped phosphate laser glass with the composition of 64P205-5.9A12O3-7.1K2O-19BaO-4.0Nd203 (Wt%) was prepared by means of reaction atmosphere dehydration process. The dehydration efficiencies of O2+POCl3 and O2+SOCl2 were studied, and the influence of identical dehydrator on the fluorescence lifetime of the prepareNd3+-doped phosphate laser glass with the composition of 64P205-5.9A12O3-7.1K2O-19BaO-4.0Nd203 (Wt%) was prepared by means of reaction atmosphere dehydration process. The dehydration efficiencies of O2+POCl3 and O2+SOCl2 were studied, and the influence of identical dehydrator on the fluorescence lifetime of the prepared Nd3+-doped phosphate laser glass with different dehydration time, dehydration temperature and bubbling flux were also analyzed. The results showed that the dehydration efficiency of POCl3 overmatches SOCl2; the dehydration rate is the fastest at the initial bubbling stage, dehydration temperature raising benefits eliminating moisture; but it′s more appropriate to dehydrate under 1 200℃ due to influence from smelting equipment and process; prolonging the dehydration time and increasing the bubbling flux are beneficial to improving dehydration efficiency; dehydration efficiency of glass is mainly influenced by the interface reaction between OH and dehydrator; fluorescence lifetime is increased with the extension of the dehydrate time and it tends to a stable valve finally; there is an optimum value for bubbling flux that is 0.8litres every minute in the experiment..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 116002 (2014)
Nano Pyramid Microstructures on Ag Film Induced by Low Energy Ion Beams
CHEN Zhi-li, LIU Wei-guo, ZHANG Jin, and WANG Meng-jiao
Ion beam sputtering induced experimental method was used to assist the silver film deposition on monocrystalline silicon(100) and the induced deposition effects of low energy Ar+ ion beams was discussed with different ion energies, fluxes and substrate temperatures at the ion incidence angle of 30°. The experimentIon beam sputtering induced experimental method was used to assist the silver film deposition on monocrystalline silicon(100) and the induced deposition effects of low energy Ar+ ion beams was discussed with different ion energies, fluxes and substrate temperatures at the ion incidence angle of 30°. The experiment indicated that temperature change had significant influence on the nano microstructure size and roughness. When the substrate temperature was between 32℃ and 100℃, the closely packed nano pyramid microstructures were obtained with grains consistent in size; when the substrate temperature rose between 32℃ and 200℃, the microstructures transverse size (λc) of samples increased rapidly, but the roughness decreased at first (32~100℃), and then increased rapidly (100~200℃). When ion flux density was within 15~45 μA/cm2 with an ion beam energy of 1 400 eV, the increase of ion beam flux densities at the same deposition temperature could achieve the nano crystal grains with unchanged lateral sizes and more compact arrangement, and slightly increased roughness; when ion beam energy was within 1 000~1 800 eV with an ion beam flux of 15 μA/cm2, the increase of ion beam energies could lead silver nano microstructure sizes to increase, and the surface roughness of samples to increase first and then decrease slowly. The pattern transformation of self-organizing nano-structure results from the interaction of spurting roughening and relaxation mechanism..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 116003 (2014)
Impact of BePP2 Deposition Rate and Thickness on the Performance of Blue Organic Light-emitting Diode
AN Tao, YUAN Jin, LIN Tao, and GAO Yong
Experiments using the vacuum thermal evaporation methods, under the monitoring of highly accurate film thickness controller, prepared the ITO/2T-NATA(25 nm)/NPB(30 nm)/BePP2(X nm)/Alq3(30 nm)/LiF(0.6 nm)/Al(80 nm)blue organic light-emitting diode structure, analyzed and experimental researched the organic light emittinExperiments using the vacuum thermal evaporation methods, under the monitoring of highly accurate film thickness controller, prepared the ITO/2T-NATA(25 nm)/NPB(30 nm)/BePP2(X nm)/Alq3(30 nm)/LiF(0.6 nm)/Al(80 nm)blue organic light-emitting diode structure, analyzed and experimental researched the organic light emitting layer of BePP2 deposition rate and thickness of the organic light emitting diode luminance and luminous efficiency. Experiments show that:When beam source furnace aperture is Φ1.5 mm, beam source furnace temperature is 120℃~150℃, BePP2 evaporation rate is smooth, the slope change is small, easy to film thickness precision control, and the film are denser to meet the needs of the device; when light-emitting layer BePP2 best deposition rate is 0.02 nm/s (evaporation temperature is 135 ℃) , and the thickness of BePP2 is 35 nm, get lights on voltage of 5.34 V, luminescence brightness of 9 100 cd/m2, 4.4 cd/A luminous efficiency of the ideal blue device can be obtained..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 123001 (2014)
A Dual-wavelength Terahertz Wave Power Splitter Based on Photonic Crystal
CHENG Wei, and LI Jiu-sheng
The combination of photonic crystal technology and THz technology provides a new approach to design novel THz wave functional devices. A dual-wavelength THz power splitter based on two-dimensional photonic crystals was proposed. A directional coupler was formed by introducing three parallel single mode waveguides, and The combination of photonic crystal technology and THz technology provides a new approach to design novel THz wave functional devices. A dual-wavelength THz power splitter based on two-dimensional photonic crystals was proposed. A directional coupler was formed by introducing three parallel single mode waveguides, and a 1×2 Y-shaped waveguide was introduced as well. Two additional rods were added at the branch of the Y-shaped structure. The coupling lengths for coupled waveguides at different frequencies were calculated by the plane wave expansion method and the principle of directional coupling, and the transmission characteristics of the power splitter were analyzed and investigated by using the finite-difference time-domain method. The results show that the power splitter can split the input field into output port1 waveguide and output port2 waveguide with equal power at frequency of 1.0 THz. However, the input beam can even be split into output port3 waveguide and output port4 waveguide with an arbitrary output energy ratio at frequency of 0.893 THz by asymmetrically changed the refractive index of the two additional rods..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 123002 (2014)
Controlled Quantum Secure Direct Communication by Using Five-particle Cluster States
NIE Yi-you, XU Wei, ZHANG Qin-nan, LI Yuan-hua, and SANG Ming-huang
A novel controlled quantum secure direct communication scheme by using five-particle cluster states is proposed. In this scheme, the quantum channel between the sender Alice, the controller Charlie and the receiver Bob consists of an ordered sequence of five-particle cluster states which are prepared by Alice. After deA novel controlled quantum secure direct communication scheme by using five-particle cluster states is proposed. In this scheme, the quantum channel between the sender Alice, the controller Charlie and the receiver Bob consists of an ordered sequence of five-particle cluster states which are prepared by Alice. After determine the security of quantum channel, Alice prepares the encoded Bell-state sequences, and Alice and Bob perform Bell-state measurements on the particles at hand, respectively, and then Charlie may make a single-particle measurement. Then Alice and Charlie tell their result to Bob, Bob can get the secret information through the analysis of their results. In our scheme, the information-carrying particles do not need to be transmitted over the public channel. Moreover, we analyze the security of the controlled quantum secure direct communication protocol, and demonstrate that our scheme is determinate and secure. In the future, our scheme might be realizable based on present experimental technology..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 127001 (2014)
Experimental Investigation of Entanglement and Bell-type Inequality of Generalized Greenberger-Horne-Zeilinger States
ZHAO Jia-qiang, CAO Lian-zhen, LU Huai-xin, and WANG Xiao-Qin
Three qubits entanglement and Svetlichny inequality of generalized Greenberger-Horne-Zeilinger states were measrued. Based on the density matrix of the generalized Greenberger-Horne-Zeilinger states, the degree of tripartite entanglement was calculated. Through the experimental investigation of the three qubits generalThree qubits entanglement and Svetlichny inequality of generalized Greenberger-Horne-Zeilinger states were measrued. Based on the density matrix of the generalized Greenberger-Horne-Zeilinger states, the degree of tripartite entanglement was calculated. Through the experimental investigation of the three qubits generalized Greenberger-Horne-Zeilinger entanglement and Svetlichny inquality, the relation between the entanglement and nonlocality property was obtained. The results show that the three-body entang lement measurement valuse are lonsistent with the theoretical values within the limits of experimental error. The expectation values of Svetlichny operator are consistent with the theoretical results. The nonlocal properties are closely related to the degree of the entangled system. The nonlocal properties decrease as the entanglement derates..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 127002 (2014)
Thin-film Solar Cell's Characteristic with Periodic Structure Based on FDFD method
WEI Yuan, XIAO Feng, WU Bo, HUANG Zhi-Xiang, and WU Xian-Liang
Using the new inhomogeneous medium interface equivalent parameter scheme combined with the finite-difference frequency-domain method, numerical analysis on mechanism of the optical properties of the thin-film solar cell with periodic structure was presented. The plasmon resonance condition was used to study the reflectUsing the new inhomogeneous medium interface equivalent parameter scheme combined with the finite-difference frequency-domain method, numerical analysis on mechanism of the optical properties of the thin-film solar cell with periodic structure was presented. The plasmon resonance condition was used to study the reflection, the transmission, the absorption characteristics, and the distribution of total field. In the low frequence point, the enhancement of the total field is obviousat the interface of the medium layer and the Ag layer, and the absorption increases significantly. Furthermore, the relationship between the enhancement factor, the structure, the incident wavelength and the angle of incidence was discussed, and its intrinsic physical mechanism was also analyzed. The enhancement factor is very large at low frequency and increases with the enhancement of the incident angle. The results show that the enhancement factor can increaseto 5.7. The proposed research work can provide a relevant theory and technical reference for the design and optimization of the actual organic thin-film solar cells..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 131001 (2014)
Design and Fabrication of Near-infrared Narrow-band Filters with Wide Rejection Band
LIU Dong-mei, WANG Xiao-juan, FU Xiu-hua, ZHANG Jing, and PAN Yong-gang
In order to meet the special requirements for filter coating of the space optical communication system, a narrow-band filter with high rejection in near-infrared band was prepared. The filter can reduce the interference of the stray light perfectly in the range of deep background. Through analyzing the characteristics In order to meet the special requirements for filter coating of the space optical communication system, a narrow-band filter with high rejection in near-infrared band was prepared. The filter can reduce the interference of the stray light perfectly in the range of deep background. Through analyzing the characteristics of the coating materials, continually optimizing the film system design curve, an easily prepared narrow-band filter film structure was obtained. Thin films were prepared through electron beam evaporation method and ion-assisted deposition technique, and the thickness of the filter was controlled using crystal-controlled and light control monitoring methods at the same time. By continually optimizing technical parameters, the transmittance of the central wavelength increased, and the filter membrane with better spectral performance was obtained successfully. After the spectrum testing, the average transmittance of the filter is lower than 0.3% at the band of 800~1 530 nm and 1 600~1 800 nm, the transmittance at 1 565 nm is higher than 92% and the full-width at half maximum of the filter is 18 nm, and the technical requirements of the optical system are satisfied..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 131002 (2014)
Calibration of Fading Curve of Imaging Plate for X-ray Diagnostics
WEI Min-xi, HOU Li-fei, YI Tao, YANG Guo-hong, and LI Jun
Based on the X-ray diffractometer in the lab, the calibration experiment of the fading curve of the imaging plate (IP) was introduced. The type of the sample was Fuji SR-2025 and the concerned signals were X-rays. A Cu X-ray tube was used as the X-ray source in the experiment while a trihydroxymethylaminomethane (TAM) Based on the X-ray diffractometer in the lab, the calibration experiment of the fading curve of the imaging plate (IP) was introduced. The type of the sample was Fuji SR-2025 and the concerned signals were X-rays. A Cu X-ray tube was used as the X-ray source in the experiment while a trihydroxymethylaminomethane (TAM) crystal was used to provide Kα monochromatic radiations. The type of IP scanner was BAS-5000 and the environment temperature was (20±1) ℃. Under the conditions that the X-rays were stable, the spatial uniformity and the line response of the IP were examined well, and the fading curve of the IP was obtained by exposing the IP on different place in different time. Fitting analysis of the fading curve was carried out and the uncertainty was discussed. The experimental results show that the instability of X-ray source is 0.7% and the spatial uniformity of IP is less than 1%; excellent linear response of the sample is also proved; at the energy point of Cu-Kα 8 027.84 eV, the fading curve of the IP decreases slowly in exponential form η(t)=0.36884·exp(－t/159.647 56)+0.633 72; the recorded signals remain 80% while 125 minutes after exposure with visible light shielding..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 43, Issue 1, 134001 (2014)
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