Journals >Acta Photonica Sinica
Contents
2011
Volume: 40 Issue 11
29 Article(s)
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Research Article
Progress and Applications of Highresolution and Superresolution Optical Imaging in Space and Biology
YAO Baoli, LEI Ming, XUE Bin, GAO Peng, YAN Shaohui, ZHAO Hui, ZHAO Wei, YANG Jianfeng, FAN Xuewu, QIU Yuehong, GAO Wei, ZHAO Baochang, and LI Yingcai
Large to observe the boundless expanse of universe with astronomical optical telescopes, small to detect the infinitesimal nanoworld with optical microscopes, optical imaging technology plays a very important role for human beings in the exploration and discovery of the mysteries of the unknown world. To see farther, Large to observe the boundless expanse of universe with astronomical optical telescopes, small to detect the infinitesimal nanoworld with optical microscopes, optical imaging technology plays a very important role for human beings in the exploration and discovery of the mysteries of the unknown world. To see farther, to see more details and to see more clearly are people′s constantly pursuing goal. The traditional optics theory has proved that all classical optical systems are diffractionlimited, i.e., the physical limit of the spatial resolution of optical systems is determined by the light wavelength and the relative aperture (or numerical aperture) of the system. Can this diffractionlimited barrier be broken through? Is it possible to continue to improve the imaging resolution of optical systems? Around this issue, this paper reviews the recent progress of a variety of highresolution and superresolution optical imaging techniques, and their developments in the fields of space exploration and biological applications..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1607 (2011)
Spacebased Telescope with Variable Resolution at Any Field Angle by Active Optical Zoom
XIE Yongjun, ZHU Shaolan, HU Shaolei, ZHAO Hui, MA Zhen, CHEN Rongli, QIU Yuehong, GAO Wei, FAN Xuewu, ZHAO Baochang, and LI Yingcai
A new kind of spacebased telescope with variable resolution at any field angle by active optical zoom is proposed theoretically. It can change the magnification of imaging system at any field angle that means the effective focal length can be changed at a limited region of interest and simultaneously maintain high resA new kind of spacebased telescope with variable resolution at any field angle by active optical zoom is proposed theoretically. It can change the magnification of imaging system at any field angle that means the effective focal length can be changed at a limited region of interest and simultaneously maintain high resolution. It comprises two static aspheric mirrors and two deformable mirrors and the focal length can be adjusted from 399 to 558.6 mm by changing the curvature of the two deformable mirrors. Comparing with the mechanical zoom systems, they are active optical zoom systems, in addition, they avoid the precisely moving of elements and reduce the response time. The imaging quality of this optical zoom system is examined by analyzing the Spot Diagrams and the Modulation Transfer Function (MTF) curves at different field of view especially about the outside of the specific FOV. The Root Mean Square (RMS) radius of field angle at 0, 0.51 and 0.7 degrees are about 1.6 μm, 1.0 μm, and 1.7 μm, respectively, and the MTF values in the Spatial Frequency (SF) of 68 lp/mm is almost unchanged at 0.7. The novel system reduces the bandwidth of data transmission and may find potential applications in remote sensing..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1619 (2011)
Micro Scanning Mirrors with Laser Diode for Pattern Generation
LI Zhao, YUAN Weizheng, WU Meng, YAN Bin, QIAO Dayong, and LIU Yaobo
A novel micro scanning mirror based on MEMS technology with a laser diode could be used in the projection of Lissajous patterns. Two micro scanning mirrors twisted in Xaxis and Yaxis are used to deflect the laser beam onto the desired projection area to draw a 2dimensional pattern. The optical scanning angle of the A novel micro scanning mirror based on MEMS technology with a laser diode could be used in the projection of Lissajous patterns. Two micro scanning mirrors twisted in Xaxis and Yaxis are used to deflect the laser beam onto the desired projection area to draw a 2dimensional pattern. The optical scanning angle of the mirror can reach ±12° in 15V square wave driving signal at twice the mirror′s resonant frequency. Given the sinusoidal movement of the mirrors in each axis, the laser beam follows a Lissajous pattern. Through analyzing the principle of the generated patterns and simulating them with Matlab, oscillation frequency combination of 2 400 Hz(Xaxis) and 2 425 Hz (Yaxis) for image generation is chosen. This combination can achieve 194×192 pixels at refresh frequency 25 Hz which is enough for movie frames. A method of projecting arbitrary images by modulating the laser diode through FPGA is given, which provides the basis for developing micro projectors..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1625 (2011)
Encapsulation′s Thermal Characteristics for Organic Electroluminescent Devices
LI Yongtao, SONG Xiaofeng, CHEN Jianlong, YAO Rihui, and WEN Shangsheng
The stability of OLED device is closely related to the encapsulation structure, while the quality of the encapsulation technology will have a direct impact on the lifetime of OLED device. Several familiar OLED encapsulation structures are introduced, adopting the thermal impedance model to analyse the impedance of thesThe stability of OLED device is closely related to the encapsulation structure, while the quality of the encapsulation technology will have a direct impact on the lifetime of OLED device. Several familiar OLED encapsulation structures are introduced, adopting the thermal impedance model to analyse the impedance of these encapsulation structures. And by using the thermal analysis module of the ANSYS finite element analysis software, the thermal characteristics of these packaging technologies are researched, obtaining the temperature field distribution of each structures. The differences of the heat dissipation performance are derived through comparison. There′s not much difference in the effect of heat dissipation between the traditional encapsulation structure and the hybrid encapsulation structure, while the Barix encapsulation structure has the best heat dissipation performance. The simulation results show that when the thickness of the glass increases from 0.5 mm to 0.9 mm, the temperature of luminous layer of traditional encapsulation structure raises 0.124 ℃, and that of Barix encapsulation structure only raises 0.262 ℃, which indicates that the heat dissipation performance has little to do with the thickness of the glass layer. When changing the airflow rate of the surface of the device to make the convection coefficient increase from 25 W/(m2·K) to 85 W/(m2·K), the temperature of luminous layer of traditional encapsulation structure decreases from 42.911 ℃ to 26.85 ℃, which has a remarkable impact on reducing the temperature of the active layer..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1630 (2011)
Effects of External Stress Applied to PM Fiberpigtail on Extinction Ratio of a Ybranch Multifunctional Integrated Optical Device
LIU Fumin, HUANG Tao, LI Ruilong, and ZHENG Guokang
Effects of external stress applied to polarizationmaintaining(PM) fiber pigtail of a Ybranch multifunctional integrated optical device on extinction ratio as well as its temperature stability are researched.Based on the analysis of stress on the fiber,expression of extinction ratio as a function of the magnitude andEffects of external stress applied to polarizationmaintaining(PM) fiber pigtail of a Ybranch multifunctional integrated optical device on extinction ratio as well as its temperature stability are researched.Based on the analysis of stress on the fiber,expression of extinction ratio as a function of the magnitude and direction of the stress is deduced,and the temperature stability of extinction ratio is discussed.Results show that the external stress is the main factor which affects extinction ratio and its stability.When the direction of stress is at an angle from the birefringent axes of a free PM fiber,the maximum extinction ratio achieves during fiberchip coupling is smaller than that of a free fiber.As a result,the polarizing direction of the chip and the slow axis of the fiber will be misaligned.The change of the stress in magnitude and direction caused by temperature results in the fluctuation of the extinction ratio.While the stress is along the birefringent axes of the fiber,it has no effect on extinction ratio,and the polarizing direction of the chip and the slow axis of the fiber can be precisely aligned.Fiber pigtails fixed with a Vgroove and with a Ugroove are analyzed in comparison,and test results show that a fixing block with a Vgroove can improve extinction ratio and its stability effectively..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1636 (2011)
Fluorescence Spectra Recognition of Hypertriglyceridemia Serum Using Principal Component Analysis and Probabilistic Neural Networks
LI Peng, ZHOU Jianmin, and ZHAO Zhimin
A novel method for recognizing fluorescence spectra of hypertriglyceridemia serum was presented based on principal component analysis and probabilistic neural networks. Firstly, two sorts of fluorescence spectra of normal and hypertriglyceridemia serum were measured at 290 nm and 350 nm excitation. And initial feature A novel method for recognizing fluorescence spectra of hypertriglyceridemia serum was presented based on principal component analysis and probabilistic neural networks. Firstly, two sorts of fluorescence spectra of normal and hypertriglyceridemia serum were measured at 290 nm and 350 nm excitation. And initial feature vectors were obtained from fluorescence intensities at intervals of 1 nm, 2 nm and 5 nm respectively. Secondly, principal component analysis was used to distill initial feature vectors and establish new sample′s feature vectors according to the cumulate reliabilities (>95%). Finally, the probabilistic neural network was designed. Recognition rates with different smoothing parameter and sampling interval were studied. Results show that recognition rates of the normal and hypertriglyceridemia serum are 95% and 100% respectively, when the sampling internal is 5 nm and the smoothing parameter is in range of 0.26~0.92..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1641 (2011)
Emission Properties of Eudoped NanoLu3Al5O12 Powders by Ultrasonic Atomization and Coprecipitation Method
HU Yuan, XIA Haiping, and ZHANG Li
Eu3+ doped nanoLu3Al5O12 powders were prepared by ultrasonic atomization and coprecipitation method with Lu2O3, Eu2O3 and Al(NO3)3·9H2O as raw materials, and the obtained powders were sintered at various temperature. Xray diffraction and scanning electron microscopy were employed to characterize the particle siEu3+ doped nanoLu3Al5O12 powders were prepared by ultrasonic atomization and coprecipitation method with Lu2O3, Eu2O3 and Al(NO3)3·9H2O as raw materials, and the obtained powders were sintered at various temperature. Xray diffraction and scanning electron microscopy were employed to characterize the particle size and phase composition of the nanopowder. The emission, excitation and phononside band spectra of Eu3+∶Lu3Al5O12 were measured. The result indicated when the sintering temperature was higher than 900℃, the luminous intensity was significantly enhanced and the optimum doping concentration of Eu3+ was 5~7 mol%. The Ω2 and Ω4 parameters of Eu3+ for optical transition were calculated from their emission spectra in terms of reduced matrix U(t) (λ=2,4,6) character for optical transitions. The results indicated that the intensity parameters Ω2 reached to minimum and electronphonon coupling to the maximum when the doping concentration of Eu3+ was ~5 mol%. With the increase of Eu3+ content, the optical parameter increased slightly and the electronphonon coupling became weaker. It suggests that the symmetry becomes weaker, the bands of Eu and O atoms become higher and the covalence of Eu and O atoms increases. The Ω2 of the powder shows an obvious lower value by comparing with those of Eu3+ in glass and crystal matrix, which is result from the symmetrical decreasing of the nanoparticles induced by a large number of defects and structural aberrations..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1646 (2011)
Backscattering Spectroscopy for Sizing Spherical Submicron Particles
YANG Yifeng, YANG Hui, ZHENG Gang, LIU Guobin, and XING Shitong
Optical single backscattering spectroscopy can be used for sizing spherical particles suspended in water, but the accuracy for sizing submicron particles cannot be satisfied. To improve the accuracy, the backscattering coefficients between 300~400 nm spectral region is applied to the determination of diameter of calibOptical single backscattering spectroscopy can be used for sizing spherical particles suspended in water, but the accuracy for sizing submicron particles cannot be satisfied. To improve the accuracy, the backscattering coefficients between 300~400 nm spectral region is applied to the determination of diameter of calibrated spherical latex polystyrene particles. Through Mie calculations, fast Fourier transform (FFT) and linear regression, the diameters of particles covering the range between 0.25 μm and 1 μm for monomodal particles are determined. The linear regression average error is ±0.02 μm, which is reduced in more than an order of magnitude compared to the data given by the preference. The method can also be applied to bimodal samples..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1652 (2011)
Raman Spectroscopic Study of the Crystallization of Intrinsic Amorphous Silicon Thin Films with a 488 nm Continuouswave Laser
DUAN Guoping, CHEN Junling, HAN Junhe, and HUANG Mingju
Intrinsic amorphous silicon thin films were prepared by plasma enhanced chemical vapor deposition method，and the crystallization of the films by 488 nm and 514 nm continuouswave laser under different power densities and irradiation time were studied by microRaman spectroscopic measurements. It is shown that intrinsicIntrinsic amorphous silicon thin films were prepared by plasma enhanced chemical vapor deposition method，and the crystallization of the films by 488 nm and 514 nm continuouswave laser under different power densities and irradiation time were studied by microRaman spectroscopic measurements. It is shown that intrinsic amorphous silicon films are able to be crystallized within 60 s at laser power densities is above 1.575×105 W/cm2. When the power density reaches to 2.756×105 W/cm2, there is transformation from amorphous silicon to singlecrystalline silicon. With the increase of the laser power density, it is still singlecrystalline silicon. At the laser power density of 2.362 ×105 W/cm, 60 s irradiation time crystallized the effect is better; and at the power density of 2.756×105 W/cm2, the effect of crystallization with 488 nm wavelength is better than that of with 514 nm in 60 s, and they are all singlecrystalline silicon..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1657 (2011)
Conditional Probability Statistical Distributions in Variant Measurement Simulations
ZHENG Jeffrey
Two quantum interactive experiments are shown in strong wavelike interference properties, ie Young double slit experiment and very lower intensive and very long time explosin experiment for quanta. This paper is based on a classical statistic scheme: Bayes statistics on Conditional Probability to propose conditional pTwo quantum interactive experiments are shown in strong wavelike interference properties, ie Young double slit experiment and very lower intensive and very long time explosin experiment for quanta. This paper is based on a classical statistic scheme: Bayes statistics on Conditional Probability to propose conditional probability measurements and relevant statistcal models to visualized complex properties of their interactions. Variant measurement simulation model is established and corresponding measring equations and perameters are formulated . Two typical cases are selected and each time has corresponding to four groups of results in 16 histograms. Under this construction, it is feasible to understand the intrinsic wavelike properties of quantum interactions. Under the conditional probability model, intrinsic wavelike statistical distributions are observed on both normal conditions and interferenced conditions in their spatial statistical distributions respectively..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1662 (2011)
A Fiber Optic Displacement Sensor with Temperature Compensation
CUI Liuzhu, JIANG Yi, and LIU Youhai
Displacement measurement is one of the most important parameters to be monitored. A Fiber Bragg Grating (FBG) displacement sensor based on double cantilever beams is developed, in which the displacement is changed to wavelength shifts of two FBGs. The influence resulted from temperature to displacement measurement is rDisplacement measurement is one of the most important parameters to be monitored. A Fiber Bragg Grating (FBG) displacement sensor based on double cantilever beams is developed, in which the displacement is changed to wavelength shifts of two FBGs. The influence resulted from temperature to displacement measurement is reduced by the differential of the two wavelengths, since they have the same wavelength shifts when they are in the same environment. The operation principle based on FBG theory is deduced, and the reasons of measurement error are analyzed. Experimental results show that the displacement sensitivity is 123 pm/mm in the range of 0~20 mm, and the temperature crosssensitivity is 17 μm/℃ after temperature compensation. With the particular advantage, this FBG displacement sensor may find tremendous applications in engineering..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1667 (2011)
A Novel Method for Simultaneous Intrusion Detection and Fire Alarm in a Single FBGbased Fiber Fence Monitoring System Configuration
WU Huijuan, LI Shanshan, LU Xianglin, WU Yu, and RAO Yunjiang
The fiber Bragg grating is sensitive to both the temperature and the strain on sensors, while the trends of their wavelength drifts differ to each other a lot. A special fiber fence monitoring system based on the fiber Bragg grating sensing network is investigated, which can realize the perimeter intrusion detection anThe fiber Bragg grating is sensitive to both the temperature and the strain on sensors, while the trends of their wavelength drifts differ to each other a lot. A special fiber fence monitoring system based on the fiber Bragg grating sensing network is investigated, which can realize the perimeter intrusion detection and the area fire protection simultaneously in a single sensing system configuration. A signal processing method is proposed which can intelligently tell if there is any threat and which kind of event it is according to the extracted signal characteristics in the time and frequency domains. Thus a normal perimeter security system possesses a second function of fire prediction, without any additional temperature sensing cables or other fire alarm systems in parallel. The results show the effectiveness of the method..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1671 (2011)
Theoretical Analysis of Dyedoped Microstructured Optical Fiber Fluorescence Sensor
LI Bingxin, and QIU Hui
Aiming at the insufficient capacity for the general optical fiber fluorescence sensors to collect the fluorescence, a novel fluorescence sensor filled with high index solution was designed that doped dyes in the air holes of microstructured optical fiber. Using the adjustable boundary condition fourier decomposition meAiming at the insufficient capacity for the general optical fiber fluorescence sensors to collect the fluorescence, a novel fluorescence sensor filled with high index solution was designed that doped dyes in the air holes of microstructured optical fiber. Using the adjustable boundary condition fourier decomposition method, the mode field distribution of this microstructured fiber was given, and the fluorescence capture fraction was calculated under the influences of optical fiber structural parameters and the refractive index of solution. The results show that small core radius and higher refractive index of solution than that of core materials can enhance the absorption of the excitation light, and increase the fluorescence capture fraction and the sensitivity of these fluorescence sensors..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1677 (2011)
Influence of Gaintoloss Ratio on the Performance of Ring Laser Gyro
MA Yanghua, LEI Jianjun, XU Hongcai, and HAN Zonghu
The intensity tuning profile is the base for mode selection and frequency stabilization in ring laser gyro (RLG), which is decided directly by the gaintoloss ratio (GTLR). To improve the performance of the RLG, the dependence of the output bandwidth on the GTLR for twomode RLG with the gain medium making of the mixtThe intensity tuning profile is the base for mode selection and frequency stabilization in ring laser gyro (RLG), which is decided directly by the gaintoloss ratio (GTLR). To improve the performance of the RLG, the dependence of the output bandwidth on the GTLR for twomode RLG with the gain medium making of the mixture of Neon isotopes (Ne20 and Ne22) is numerically analyzed, with the consideration of comprehensive broadening (both homogeneous broadening and inhomogeneous broadening). It is shown that the output bandwidth increases monotonically with the GTLR of RLG. The intensity tuning profiles with different GTLRs of RLG are simulated and the results show that the intensity tuning profiles can be divided into three typical forms, according to the relative value of the output bandwidth to the adjacent longitudinal mode spacing, exhibiting great agreement with the experimental ones. The potential influence of improper GTLR selection on the application performance of RLG is analyzed and experimentally demonstrated. The ideal selection of GTLR for RLG is proposed, that is, the output bandwidth of the RLG should be approximately equal to its adjacent longitudinal mode spacing..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1682 (2011)
Calibration of Phaseshifted Sensitivity of Optical Fiber Hydrophone in the Frequency Range 20 Hz to 10 kHz
CHEN Yi, ZHANG Jun, ZHANG Min, and WANG Liwei
Through accurately measuring the phaseshifted sensitivity of the head of optical fiber hydrophone using phased generated carrier demodulation technique, calibration of phaseshifted sensitivity of optical fiber hydrophone in the frequency range 20 Hz to 10 kHz was realized. At the frequencies from 20 Hz to 1.25 kHz, tThrough accurately measuring the phaseshifted sensitivity of the head of optical fiber hydrophone using phased generated carrier demodulation technique, calibration of phaseshifted sensitivity of optical fiber hydrophone in the frequency range 20 Hz to 10 kHz was realized. At the frequencies from 20 Hz to 1.25 kHz, the calibration method was standing wave tube comparison method. And at the frequencies from 1.25 kHz to 10 kHz, the calibration method was freefield toneburst comparison method. The No.35 TMD optical fiber hydrophone was calibrated by the calibration system. The calibration results show that the phasedshifted sensitivities measured by two methods are very close, and the deviation value of sensitivity at the frequency 1.25 kHz is only 0.8 dB. Analysis of measurement uncertainties prove that the expand uncertainty (at k=2) of this calibration system is 0.9 dB..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1686 (2011)
Low Misstatement Rate Distributed Optical Fiber Fence Intrusion Detection System by Variety of Wavelet Decomposition Method
WU Xiuwei, WU Huijuan, RAO Yunjiang, WU Yu, and ZHAO Tian
Because the distributed fiber fence system based on the phasesensitive optical timedomain reflectometer is very sensitive to its ambient environments, high false alarm rate is a quite normal phenomenon which is very annoying and difficult to avoid. In this paper, different wavelet decomposition methods are compared fBecause the distributed fiber fence system based on the phasesensitive optical timedomain reflectometer is very sensitive to its ambient environments, high false alarm rate is a quite normal phenomenon which is very annoying and difficult to avoid. In this paper, different wavelet decomposition methods are compared for extracting the singularity information buried in the noisy intrusion signals. A comprehensive judgment method is proposed which combines several different wavelet decomposition methods to reduce the system′s false alarm rate. The experiment results show that different wavelet decomposition methods can extract different detail information at different levels, thus it can provide much more sufficient information and conditions for the decisionmaking process. The false alarm rate of the new method can be lowered to none or once per 24 hours, which is much lower than the other methods based on a single wavelet analysis way. It can efficiently improve the system′s robustness and its decision′s confidence level..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1692 (2011)
Fourier Transform Profilometry Using Zero Frequency Elimination Based on Gray Modulation
LIU Dahai, and LIN Bin
The bicolor sinusoidal fringe patterns are used to depress the effect of zero frequency extension on fundamental frequency component in Fourier transform profilometry.A novel intensitymodulated method is proposed to eliminate the zero frequency component,which can improve the measuring precision and range.Two compounThe bicolor sinusoidal fringe patterns are used to depress the effect of zero frequency extension on fundamental frequency component in Fourier transform profilometry.A novel intensitymodulated method is proposed to eliminate the zero frequency component,which can improve the measuring precision and range.Two compounding monochrome fringe patterns with phase difference of π can be obtained by separating color channel of one color image.After calibration of intensity modulation and zero component elimination,the shape is obtained.The feasibility of the algorithm is validated by both theoretical simulation and experiment performance.Compared to the traditional phase shift method to eliminate the zero frequency component,this method has a significant advantage at speed and is suitable for realtime measurement of threedimensional objects..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1697 (2011)
Rapid Subsequence Match in Pseudo Random Sequence Projection Based Threedimensional Measurement System
CHEN Liangfeng, and LI Yong
A rapid algorithm for threedimensional measurement was proposed based on pseudo random sequence projection. Firstly, a multilayer table was constructed according to source sequence and length of subsequence. Then, the operation of looking up table was performed from table on top layer to which on bottom layer corresA rapid algorithm for threedimensional measurement was proposed based on pseudo random sequence projection. Firstly, a multilayer table was constructed according to source sequence and length of subsequence. Then, the operation of looking up table was performed from table on top layer to which on bottom layer corresponding to the character in subsequence from left to right. Finally, the position of subsequence was obtained by looking up the table on bottom layer. That is to say, the address of table on second layer was obtained by looking up table on top layer according to first (left) character in subsequence. Then, the address of table on third layer was obtained by looking up table on second layer according to second character in subsequence. The rest can be done in the same manner. Finally, the address of table on bottom layer was obtained and the position of subsequence was obtained by looking up this table. The theory analysis and experimental results were presented. The results show that the speed of algorithm based on lookup table for representative scene is about 60 times faster than the general ones on mainstream computer..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1702 (2011)
Three-dimensional Capture and Display of Real Scene with Video Speed
Li Yong, Lu Shijiang, Song Fang, Gao Zhiqiang, Jin Hongzhen, and Wang Hui
An approach for capture and display three-dimensional real scene with video speed was proposed. A real-time three-dimensional imaging system using fringe projection was designed. And a real-time color holographic display system using liquid crystal spatial light modulator was designed. Two fringe patterns with phase shAn approach for capture and display three-dimensional real scene with video speed was proposed. A real-time three-dimensional imaging system using fringe projection was designed. And a real-time color holographic display system using liquid crystal spatial light modulator was designed. Two fringe patterns with phase shift π and an encoding pattern were adopted in 3D imaging system. Absolute phase was obtained and isolated objects could be measured. A high speed projector was obtained by modifying a projector using digital micromirror device. Three-dimensional capture with video speed was realized by combining the modified projector and high speed camera. The color image and range image of three-dimensional scene was captured with the proposed three-dimensional imaging system. Then, Fresnel holograms were produced with these three-dimensional data. Finally, color threedimensional images were reconstructed with proposed display system. The speed of capture and display reaches 60 fps..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1706 (2011)
Analysis of Particle Holograms Based on Hough Transform and Linear Chirp Transform
CEN Yuting, KUANG Shengping, ZHAO Xiaojuan, and HAN Peng
A method on particles holograms analysis was proposed based on Hough transform and linear chirp transform. Particles sizes were calculated using the position of minimum point in space domain and frequency domain. After pretreatment of noise reduction filtering and edge detection to the holograms, string midpoint Hough A method on particles holograms analysis was proposed based on Hough transform and linear chirp transform. Particles sizes were calculated using the position of minimum point in space domain and frequency domain. After pretreatment of noise reduction filtering and edge detection to the holograms, string midpoint Hough transform was used to detect the center position of the particles, and the intensity distribution curve was described according to the cumulative normalized gray value of each circumference. Light intensity signal is applied to Fourier transform, combined with linear chirp transform for local spectral amplification, and then the accurate position of first minimum point in frequency domain can be known. Finally the particle sizes can be resolved by the obtained position in space and frequency domain. In terms of further particle spacing of particle holograms, numerical simulation results show that the method error were 2.5% or less..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1711 (2011)
Design of Highbrightness Fibercoupled Diode Laser System Based on Astigmatism and Ideal Imaging Theories
OU Xiang, XIONG Lingling, ZHANG Pu, DING Xiaochen, JIA Shuhai, and LIU Xingsheng
A highbrightness fibercoupled diode laser system is designed, based on the principle of astigmatism and ideal light source imaging theory. As an example, details of the calculation methods and design steps of the fiber coupled laser diode are given whose wavelength is 808 nm and output power is 10 W. Semiconductor laA highbrightness fibercoupled diode laser system is designed, based on the principle of astigmatism and ideal light source imaging theory. As an example, details of the calculation methods and design steps of the fiber coupled laser diode are given whose wavelength is 808 nm and output power is 10 W. Semiconductor laser beam can be coupled into the 50 μm core diameter optical fiber with a numerical aperture of 0.22. It is found that this fibercoupled system has an output power of 9.712 W, a coupling efficiency of 97.12% and a power density of 1.1224×106 W/cm2. The proposed method is simple in principle, and the designed fibercoupled system has high coupling efficiency, small size and strong practical value..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1718 (2011)
Electrooptical Tunable Filter with Symmetric Generalized Fibonacci Photonic Crystal
LIU Xiao, ZHOU Jun, ZHU Benqiang, and JIN Li
A structure of symmetric generalized Fibonacci photonic crystal is proposed to design the electrooptical tunable filters based on the electrooptical effect of LiNbO3 material. The characteristics of the tunable filter are theoretically investigated by the transfer matrix method. The numerical simulation results show A structure of symmetric generalized Fibonacci photonic crystal is proposed to design the electrooptical tunable filters based on the electrooptical effect of LiNbO3 material. The characteristics of the tunable filter are theoretically investigated by the transfer matrix method. The numerical simulation results show that the channel wavelength of the filter can be modulated by the external electric field which is applied on the LiNbO3 layers without changing the geometrical structure of the symmetric generalized Fibonacci photonic crystal, and the channel wavelength will linearly move to short wavelength as the increase of the external electric voltages. In addition, if the external electric voltage is fixed, the channel wavelength will move to short wavelength as the increase of the incident angle; if the incident angle is fixed, the channel wavelength will move to short wavelength for the increase of plus external electric voltage, while the channel wavelength will move to long wavelength for negative external electric voltage. Lastly, the characteristics of the tunable multichannel filter with double external electric fields are discussed. It provides an important reference for design of novel photonic crystal devices..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1723 (2011)
Novel Highly Bireferingent Photonic Crystal Fiber Based on an Elliptical Hole Fiber Cladding and a Fiber Core of Doublemicrohole Units
LIU Xuan, WU Genzhu, CHEN Daru, LIU Jun, and LU Qijing
A novel highly birefringent photonic crystal fiber (PCF) with elliptical air holes in the fiber cladding and arrays of subwavelength doublehole units with size of about 0.16 μm in the fiber core was proposed. Dispersion and birefringence property of the proposed PCFs was investigated by using a fullvector finiteelemA novel highly birefringent photonic crystal fiber (PCF) with elliptical air holes in the fiber cladding and arrays of subwavelength doublehole units with size of about 0.16 μm in the fiber core was proposed. Dispersion and birefringence property of the proposed PCFs was investigated by using a fullvector finiteelement method (FEM) and anisotropic perfectly matched layers. Curves between modal birefringence (confinement loss) of the proposed PCFs and the wavelength of the input light for PCFs with different parameters of ellipticity, normalized area，diameter of the two microholes, distance between the two microholes are reported in details. Simulation results showed that high birefringence (larger than 0.001) and ultralow confinement loss (less than 0.000 2 dB/km) are achieved. The proposed design of the PCF is an approach to achieve both the high birefringence and the low confinement loss by introducing asymmetric microstructure both in the fiber cladding and in the fiber core..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1728 (2011)
Photonic Localization in Reverse Opal Photonic Crystal Constituted by TiO2 in Middle Infrared Band
XU Qingjun, and ZHANG Shiying
In oder to obtain the influence on the photonic localization in reverse opal photonic crystal constituted by TiO2, the photonic localization parameters are calculated numerically and analyzed theoretically, based on the Mie scattering theory and the low density approximation. It was found that the incidence wavelength In oder to obtain the influence on the photonic localization in reverse opal photonic crystal constituted by TiO2, the photonic localization parameters are calculated numerically and analyzed theoretically, based on the Mie scattering theory and the low density approximation. It was found that the incidence wavelength and scattering body′ size have the obvious influence on localization phenomena in thesurplus ray zone of the oxide. The results show that the photonic localization phenomena appear in middle infrared band (13.3~15.3 μm) under the conditions of scatterer′s density of 10% and relative refractive index greater than 3.8. With the increase of the scattering body′s radius, the localization area shifts to long wavelength; simultaneously, the localization parameter firstly increases, then decreases. These research results can provide an academic reference to achieve experimentally the photonic localization phenomenon in the kind of photonic crystal..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1733 (2011)
Effect of Pump Area on Lasing Modes in Two Dimensional ZnO Nanorods Random Media
YOU Qiaoqin, LI Bingxiang, YANG Huan, HU Dabo, LEI Yuan, WANG Yueming, and XIE Yingmao
Based on the growth and photoluminescences experiment of Zinc Oxide (ZnO) nanorods, the structrue model of twodimensional random media, in which the location and radius of ZnO nanorods are all disordered, was constructed. Using ZnO gain model, the spectrum characteristics and spatial distribution of optical field at sBased on the growth and photoluminescences experiment of Zinc Oxide (ZnO) nanorods, the structrue model of twodimensional random media, in which the location and radius of ZnO nanorods are all disordered, was constructed. Using ZnO gain model, the spectrum characteristics and spatial distribution of optical field at some resonant peak in ZnO nanorods random media were simulated numerically by means of the finite difference time domain method, and the localized mode was found. The effect of pump area on stimulated radiation of the local mode in ZnO nanorods random media was studied from four aspects: changing the pump intensity, increasing the pump size every two columns from left to right, only pumping a zone of localized mode, and increasing the excitation area (the number of the ZnO nanorods) in localized area and nonlocal area respectively when the pump intensity is fixed. The results show: there exists a critical pump power; when the pump intensity is smaller than pump intensity at the lasing threshold, no localized mode can be excited with the size of the pump area; when the pump power reaches above the critical pump power, in the case of different pump powers, localized modes can be excited with different critical pump sizes; when the power size is fixed, the relative light intensity increases with the increasing of the pump intensity and the relative light intensity increases rapidly when the pump intensity exceeds the lasing threshold..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1738 (2011)
Tight Focusing of Stochastic Electromagnetic Vortex Beams
[in Chinese], [in Chinese], and [in Chinese]
Based on vectorial Debye theory, the focusing properties of stochastic electromagnetic vortex beams by a high numerical aperture objective are investigated. The influence of numerical aperture of the objective, the degree of polarization, the topological charges, and the transverse coherent length of the incident vorteBased on vectorial Debye theory, the focusing properties of stochastic electromagnetic vortex beams by a high numerical aperture objective are investigated. The influence of numerical aperture of the objective, the degree of polarization, the topological charges, and the transverse coherent length of the incident vortex beam on the intensity and spectral degree of coherence in the focal region are investigated. Studies in intensity distribution reveal that elliptical light spots and the flat top beam, which have many applications, can be obtained by selecting certain parameters. The degree of coherence at a point between two orthogonal electric field components, the degree of coherence at a pair of points between two identical electric field components, and the degree of coherence at a pair of points between two orthogonal electric field components of stochastic electromagnetic vortex beams in the focal plane are investigated respectively. It is shown that the topological charges and transverse coherent length of incident vortex beams have very obvious effects on the coherence of focused beams..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1744 (2011)
Crosstalk in Scintillating Fiber Array Detector Irradiated by Highenergy Xray
MA Qingli, TANG Shibiao, XU Shimin, DANG Shuangping, and ZOU Jiwei
The crosstalk in plastic scintillating fiber array detector with highenergy gamma incident was studied through MonteCarlo simulation. The relationship between crosstalk and lead layer was also analyzed. Modulate transfer function(MTF),which shows quantity of spatial resolution of imaging detector, was analyzed and The crosstalk in plastic scintillating fiber array detector with highenergy gamma incident was studied through MonteCarlo simulation. The relationship between crosstalk and lead layer was also analyzed. Modulate transfer function(MTF),which shows quantity of spatial resolution of imaging detector, was analyzed and compared in order to get the MTF results caused from the difference thickness of lead layer. The results show that there exists severe crosstalk in the detector irradiated by highenergy particles, and the lead layer can reduce the effect. On the other hand, the pixel of detector may become big as the lead layer is introduced, which can reduce the spatial resolution. Through the simulation computation, it is proved that the right thickness of lead layer will reduce crosstalk and increase spatial resolution of imaging detector..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1751 (2011)
Linear Transmission Spectrum and the Nonlinear Bistable Characteristics of Magnetooptic Fiber Bragg Gratings Based on the Lorentzian Function Perturbation
KONG Deqian, and ZHANG Guanmao
Based on the nonlinear coupled mode theory, by using the reversely recursive RungeKutta method, the influence of introducing the Lorentzian function perturbation to the magnetooptic coupling coefficient on the linear transmission spectrum and the bistable characteristics of magnetooptic fiber Bragg gratings is invesBased on the nonlinear coupled mode theory, by using the reversely recursive RungeKutta method, the influence of introducing the Lorentzian function perturbation to the magnetooptic coupling coefficient on the linear transmission spectrum and the bistable characteristics of magnetooptic fiber Bragg gratings is investigated numerically. The results of the study show that introducing the Lorentzian perturbation to the magnetooptic coupling coefficient can open up a narrow transmission window in the linear transmission spectrum stopband. The perturbation widths and the perturbation center positions can affect the position, the width, and the peak amplitude of the transmission window. The bistable characteristics can show significant differences when the perturbation widths and the perturbation center positions change. The bistable characteristics can be further optimized by choosing perturbation parameters reasonably..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1755 (2011)
An Integral Histogrambased Particle Filtering Tracking Method
QIU Jiatao, LI Yushan, WANG Cailing, and LIU Yang
A particle filtering tracking method is presented with low computational complexity using integral histogram technique. Integral orientation histogram is adopted for the construction of a response map. Based on this response map, a proposal is constructed such that particles are drawn from regions of the state space wiA particle filtering tracking method is presented with low computational complexity using integral histogram technique. Integral orientation histogram is adopted for the construction of a response map. Based on this response map, a proposal is constructed such that particles are drawn from regions of the state space with high likelihood. Also, an integral color histogrambased likelihood model is proposed. Simulation results show that the proposed tracking method has lower computational complexity than that using straightforward histogram extraction method when using large number of particles for tracking large objects. The results are much accurate compared with that using traditional color MeanShift method under illumination change conditions..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 11, 1761 (2011)
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