Journals >Acta Photonica Sinica
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2011
Volume: 40 Issue 7
30 Article(s)
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Research Article
Fiberoptic Security System Based on Phase Carrier Multiplexing and its Realization Methods
WU Yuan, BIAN Pang, and XIAO Qian
A novel technology for security system was proposed based on phase carrier modulationdemodulation in this paper, to realize the multiplex of the white light interference system. In several sensing terminals of the single core feedback white light interference system, there are several phasemodulators which worked at A novel technology for security system was proposed based on phase carrier modulationdemodulation in this paper, to realize the multiplex of the white light interference system. In several sensing terminals of the single core feedback white light interference system, there are several phasemodulators which worked at different frequencies. The trigger signal in the different interference subsystems could be separated by phase modulation technology. The signals of the different interference subsystems could be demodulated by phase demodulation technology to have the independent time signal of the different interference subsystems. This method adopted fiber to sense certain environment vibration, obtained the vibration signal using whitelight interferometry, and then located the vibration zone by means of phase carrier multiplexing. Theoretical analysis and experimental results show that it can realize the share of interference system of different sensing terminals based on the technology of phase carrier multiplexing. This technology can decrease the complexity of the security system and reduce the system cost. This method is able to monitor the vibration and locate the intrusion zone in realtime rapidly, effectively and sensitivity. Therefore this technology can be applied in large area and long distance multiple zone intrusion detection systems..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 967 (2011)
Stabilizational Tracking Technology for Atmospheric Laser Communication System
LIU Yunqing, JIANG Huilin, and TONG Shoufeng
Aiming at stabilizational tracking technology for atmospheric laser communication system, sensitivity characteristics of the beam position detectors(CCD and QD) were analyzed. Five kinds of turbulence effects such as beam wander, intensity fluctuations,dispersed spot, angle of arrival fluctuation and beam spreading forAiming at stabilizational tracking technology for atmospheric laser communication system, sensitivity characteristics of the beam position detectors(CCD and QD) were analyzed. Five kinds of turbulence effects such as beam wander, intensity fluctuations,dispersed spot, angle of arrival fluctuation and beam spreading for tracking precision and their mathematical models were discussed. Then, simulation results of turbulence effects under various conditions were analyzed. Both the theoretical analysis and the experimental results show that tracking error of shape center capturing algorithms is less than tracking error of centroid localization algorithm..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 972 (2011)
Phase Shifting Shadow Moiré by Iterative Leastsquares Fitting
DU Hubing, ZHAO Hong, LI Bing, LI Zhengwei, ZHENG Liang, and FENG Leilei
Shifting shadow moiré iterative algorithm and procedures for both the calibration of phase shifter and noise reduction approaches are proposed. Compared with the traditional shifting shadow moiré method, the proposed method is insensitive to the height dependent effects and can determine the pointwise phase Shifting shadow moiré iterative algorithm and procedures for both the calibration of phase shifter and noise reduction approaches are proposed. Compared with the traditional shifting shadow moiré method, the proposed method is insensitive to the height dependent effects and can determine the pointwise phase step during the process of demodulation. The effectiveness of the proposed method is demonstrated by both simulations and experiments. They are shown that the proposed method can effectively minimize the effects of the phaseshifting errors and possess a superior performance than existing typical phase shifting algorithms in shifting shadow moiré technique..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 978 (2011)
60 GHz OFDMRoF System Based on RS Code Concatenated with PTCM Technology
ZENG Guanjun, CHEN Lin, YU Jianjun, XIAO Jiangnan, CAO Zizheng, and Li Fan
SSMI and FF in 60 GHz OFDMRoF system were analyzed. RS code concatenated with PTCM and symbol interleaver were applied in the 60 GHz OFDMRoF system to reduce the these bad impacts of optical fiber. Using symbol interleaver to scatter errors in the subcarries of OFDM,RS with high code rate concatenated with PTCM coulSSMI and FF in 60 GHz OFDMRoF system were analyzed. RS code concatenated with PTCM and symbol interleaver were applied in the 60 GHz OFDMRoF system to reduce the these bad impacts of optical fiber. Using symbol interleaver to scatter errors in the subcarries of OFDM,RS with high code rate concatenated with PTCM could correct bit errors caused by intersubcarrier interference and frequency fading to improve the performance of system. Simulation results show that errors in subcarriers become welldistributed and will be favorable for error correction.The receiver sensitivity of 2.5 Gb/s OFDM signal adopted the 64QAM modulation format with RSPTCM can save up to 5 dB receive power relative to 2.25 Gb/s OFDM signal with the uncoded 16QAM scheme..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 983 (2011)
Optical Switch Based on Optical Loop Mirror with Erbiumdoped Fiber and Microstructure Fiber
ZHAO Juan, XU Wenbo, SU Xianxu, LI Wei, YANG Qing, and CHEN Ming
A low switchingpower alloptical switch was designed. The erbiumdoped fiber and the microstructure fiber were inserted into the Sagnac loop mirror simultaneously. Under the effect of the pump modulation, signal light was amplified when passing the erbiumdoped fiber. The symmetry of the loop was broken, two counterpA low switchingpower alloptical switch was designed. The erbiumdoped fiber and the microstructure fiber were inserted into the Sagnac loop mirror simultaneously. Under the effect of the pump modulation, signal light was amplified when passing the erbiumdoped fiber. The symmetry of the loop was broken, two counterpropagating signal lights in the loop acquire nonlinear phase due to the crossphase modulation effect, and the light switch was realized. The theoretical analysis shows that while the signal light goes through erbiumdoped, the larger gain it gets, and the higher coefficients of the microstructure fiber is, the lower switch power is. Furthermore, the transmission rate of signal light in the loop varies with the phase difference of the two counterpropagating signal lights into cosine changes. the simulation results shows that switching power is 26.73 mW, which agrees with the theory..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 989 (2011)
Piezoelectric Ceramic Characteristics Using Fiber Grating Sensor
YU Youlong, TAN Ling, ZOU Ligang, and WANG Hao
A method for characteristics of piezoelectric ceramics was presented using a fiber Bragg grating sensor.An unbalanced Michelson interferometer was utilized to demodulate the fiber Bragg grating sensor signals.The relationship between the displacement of piezoelectric ceramic and the applied voltage was shown by observiA method for characteristics of piezoelectric ceramics was presented using a fiber Bragg grating sensor.An unbalanced Michelson interferometer was utilized to demodulate the fiber Bragg grating sensor signals.The relationship between the displacement of piezoelectric ceramic and the applied voltage was shown by observing the phaseshift induced by wavelengthshift.The hysteretic and creep properties of the piezoelectric ceramic were demonstrated experimentally,and the applied voltagedisplacement curve and the creep curve were obtained.The results show that the fluctuations of light power had no effect on hysteretic,and the voltage direction has nothing with creep..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 994 (2011)
DarkPulse Brillouin Optical Time Domain Analyzer for kmRange Detection with Only One Fiber Section
LIU Lei, ZHANG Zhiguo, ZHANG Min, LIU Mingtao, and ZHANG Xiaopin
In darkpulse Brillouin optical time domain analyzer (DPBOTDA) DPBOTDA the effective sensing length is greatly limited by the severe interaction between the QuasiCW pump light and pump light. A simple DPBOTDA was proposed to prolong the total sensing length without using multisection fibers. To mitigate the impactIn darkpulse Brillouin optical time domain analyzer (DPBOTDA) DPBOTDA the effective sensing length is greatly limited by the severe interaction between the QuasiCW pump light and pump light. A simple DPBOTDA was proposed to prolong the total sensing length without using multisection fibers. To mitigate the impact of the high power QuasiCW pump light, both Brillouin gain and loss effect along fiber were measured simultaneously in this scheme, yielding the Brillouin signal by subtracting the two side bands of the optical carrier suppressed (OCS) Stokes light. Based on this proposal, the total sensing length in DPBOTDA could be increased. Simulations and discussions were conducted to validate the proposal, and the results are useful for designing high spatial resolution distributed Brillouin fiber sensor..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 998 (2011)
Hydrogen Sensor Based on Dshaped Fiber Bragg Grating Coated with WO3Pd Composite Films
DAI Jixiang, YANG Minghong, CHEN Yun, CAO Kun, LIAO Junsheng, and HANG Pengcheng
40 nm WO3Pd composite film was sputtered on the sideface of sidepolished fiber Bragg grating (Dshaped FBG). The FBG sensing head with 40 nm WO3Pd composite film was firstly prepared by a 5 nm WO3 coating realized with radio frequency（RF）sputtering process, followed by depositing 5 nm WO3/Pd composite film, and the40 nm WO3Pd composite film was sputtered on the sideface of sidepolished fiber Bragg grating (Dshaped FBG). The FBG sensing head with 40 nm WO3Pd composite film was firstly prepared by a 5 nm WO3 coating realized with radio frequency（RF）sputtering process, followed by depositing 5 nm WO3/Pd composite film, and then finished with 30 nm Pd film by directcurrent(DC) sputtering method. SEM results show that WO3Pd composite film still has good surface morphology after several cycle′s hydrogen response, which indicates WO3Pd composite film has good mechnical property. The experiment results demonstrate hydrogen sensor has good repeatability under different concentration hydrogen. Compared to standard FBG coated with same hydrogen sensitive film, the sensitivity of Dshaped FBG is increased by 200%. When the hydrogen concentration is 6% in volume, the wavelength shift of Dshaped FBG is about 15 pm. Dshaped FBG hydrogen sensor has great potential in hydrogen′s measurement..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1003 (2011)
Reflection on Surface Photovoltage Spectroscopy for Transmissionmode GaAs Photocathodes of Different Active Layer Thickness
CHEN Liang, QIAN Yunsheng, and CHANG Benkang
Equations for surface photovoltage spectroscopy were deducted,by solving the ondimensional diffusion equation for equilibrium minority carriers of transmissionmode GaAs phtotocathode.Through measuring the surface photovoltage curves for GaAs photocathodes with the active layer thichness of 1.6 and 2.0μm,doping concenEquations for surface photovoltage spectroscopy were deducted,by solving the ondimensional diffusion equation for equilibrium minority carriers of transmissionmode GaAs phtotocathode.Through measuring the surface photovoltage curves for GaAs photocathodes with the active layer thichness of 1.6 and 2.0μm,doping concentration of 1×1019 cm－3,experiments and fitting curves fit very well.By leading the formulas for integral sensitivity of surface photovoltage spectroscopy,the inflection of active layer thickness for integral sensitivity was analyzed under certain body parameters through emulations.It was found that GaAs photocathodes have a optimal active layer thickness and the backinterface recombination velocity inflects more on optimal thickness than electron diffusion length.Furthermore,GaAlAs window layer could help to well reduce the backinterface recombination velocity for active layer thickness..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1008 (2011)
Dynamic Research for Rotating Mirror of Ultrahigh Speed Camera
YU Chunhui, LI Chunbo, LIU Chunping, PAN Ying, CHAI Jinlong, WANG Hongzhi, LI Jingzhen, and HUANG Hongbin
A model and harmonic simulation analysis and experiments have been done separately by the finite element analysis software ANSYS and its first five natural frequencies,vibration models and the frequency response curve of rotating mirror were obtained.In the displacement frequency response curve of rotating mirror,the rA model and harmonic simulation analysis and experiments have been done separately by the finite element analysis software ANSYS and its first five natural frequencies,vibration models and the frequency response curve of rotating mirror were obtained.In the displacement frequency response curve of rotating mirror,the resonance bands of torsional vibration and bending vibration were overlapped,and the maximum peak value at the first bending vibration was greater than others.The stress of the first bending vibration was much larger than the others and the maximum stress appeared in the shaft.The main form of failure is the damage of the shaft,and the front bending vibration is the main reason of rotating mirror failure.With the model of rotating mirror natural frequency sensitivity compiled by ANSYS Parametric Design Language ,the numerical analysis and experiment of rotating mirror natural frequency have been done using the Probabilistic Design System of ANSYS to study the interrelationship between physical dimensions and the natural frequencies.The numerical results reveal that the dependency of the circumcircle radius R5 of mirror body and the radius of shaft 2 with the same frequency is opposite,and the degree of correlation of R5 and R2 is higher than anther.The results of experiment show that the change mode and degree due to the same change of different structural parameters of rotating mirror is identical with numerical analysis.This study provides a quantifiable indicator for dynamic design of rotating mirror..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1013 (2011)
Infrared Dim Target Detection Based on MultiStructural Element Morphological Filter Combined with Adaptive Threshold Segmentation
MA Wenwei, ZHAO Yongqiang, ZHANG Guohua, JIE Feiran, PAN Quan, LI Guoqiang, and LIU Yongjin
Aiming at detection puzzle of small target in grayscale image with low SNR,the characteristics of infrared small targets were analyzed and a detection algorithm was put forward based on multistructural element morphological filter combined with adaptive threshold segmentation.In view of the continuity and regularity oAiming at detection puzzle of small target in grayscale image with low SNR,the characteristics of infrared small targets were analyzed and a detection algorithm was put forward based on multistructural element morphological filter combined with adaptive threshold segmentation.In view of the continuity and regularity of motion for target and the randomness of generation for noise,and considering the characteristics of structure element,the design of morphological filter and a technique via assembly line and pipe scheme were considered to detect target trajectory.Experiments show that the algorithm is able to obtain excellent results toward low SNR infrared image under complex background,and has high detection probability,high speed and low false alarm rate..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1020 (2011)
A Method of Color Image Retrieval Based on Visual Attention Model
HUANG Chuanbo, and JIN Zhong
The feature based on visual attention model is a new feature that can objectively interpret the highlevel concepts. High retrieval efficiency will be achieved and the semantic gap in image retrieval can be also reduced effectively if visual attention mechanism is adopted. An improved Itti′s visual attention model, insThe feature based on visual attention model is a new feature that can objectively interpret the highlevel concepts. High retrieval efficiency will be achieved and the semantic gap in image retrieval can be also reduced effectively if visual attention mechanism is adopted. An improved Itti′s visual attention model, inspired by human visual perception, is proposed. Primary component map is used to take place of intensity map, and the information of texture coarseness is brought in the improved Itti′s model. A novel image retrieval algorithm is proposed based on visual attention distribution feature. Firstly, the image is divided into 38 feature maps by the improved Itti′s visual attention model. Then, by the fixed fourbyfour grid of subregions, the visual attention distribution feature to image retrieval is constructed according to statistical distribution of the 38 feature maps which contain most of the structural information of the image. The experimental results show that the proposed method has better retrieval performance..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1025 (2011)
Principal Component Analysis Method for Muitiplicative Noise Removal
YAO Lili, FENG Xiangchu, and LI Yafeng
The further application of Radar image system relies on the quality of denoising from images. By analyzing the existing denoising algorithms, a new algorithm was presented using principal component analysis for removing multiplicative noise, based on local similarity of images. Multiplicative noise by logarithmic transThe further application of Radar image system relies on the quality of denoising from images. By analyzing the existing denoising algorithms, a new algorithm was presented using principal component analysis for removing multiplicative noise, based on local similarity of images. Multiplicative noise by logarithmic transformation could be converted into the additive noise for processing. Type analysis of the noise in the logarithmic domain was given. In the image logarithm domain, training sample blocks were selected by nonlocal method, and the principal component analysis was used to extract the main features of image blocks. A threshold principle, was proposed by linear minimum meansquare error estimate, which adapted to the signal message. The denoising images were obtained by biased estimation. Experiment results show that the presented method is valid. Compared with the existing variational methods,the new method has higher peak signal to noise ratio and better visual effect. That the performance of the proposed method is practical at a certain extent..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1031 (2011)
A Background Reconstruction Algorithm Based on Pixel Sequence Pattern Classification
YU Chunyan, WU Liqiao, and LI Jianming
Background reconstruction is a fundanmental task of video and image processing. To overcome disadvantages of traditonal backgound reconctruction algorithms, such as complex computation and distortional backgound, a pratical backgound reconstruction algorithm was proposed based on pixel sequence pattern classification. Background reconstruction is a fundanmental task of video and image processing. To overcome disadvantages of traditonal backgound reconctruction algorithms, such as complex computation and distortional backgound, a pratical backgound reconstruction algorithm was proposed based on pixel sequence pattern classification. The pixel sequence patterns, extracted through calculating differences between sequential two frames, were classified by means of pixel sequence patterns’ charateristics determined by those differences. Furthermore, independent background extraction and background update mechanisms were destined for pixels with different pixel sequence patterns. Simulation results indicate that correct backgrounds of video with moving targets can be reconstructed without the models of background and moving targets. And, the background can be effiently updated when backgound is changed..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1036 (2011)
An Improved Thresholding Segmentation Algorithm of Ball Grid Array Xray Digital Image
LI Wei, and ZHANG Shuo
The Xray image of BGA has low SNR characteristic and nonuniformity characteristic. Traditional threshold segmentation is unable to segment BGA solder from background accurately. By analyzing of the histogram of the BGA Xray image, Wiener filtering was used in the image preprocessing procedure. The filter parameter waThe Xray image of BGA has low SNR characteristic and nonuniformity characteristic. Traditional threshold segmentation is unable to segment BGA solder from background accurately. By analyzing of the histogram of the BGA Xray image, Wiener filtering was used in the image preprocessing procedure. The filter parameter was adjusted for different images. Low and high smooth operations were used in minor and bigger differences, respectively. OTSU method was implemented to select a initial threshold, and an improved threshold segmentation algorithm was used to segmented images based OTSU method. It meaned that the BGA image would not be processed directly by OTSU method. In fact, a better threshold would be found by calculating the mean value and calculating the max statistic of pixels. A new pixel value was chosen to replace all pixels value of the background in BGA image. The experimental results show that this algorithm improves the segmented effect compared with the traditional OTSU method..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1046 (2011)
Design Method of a Freeform HMD System with Large Pupil Size
YANG Bo, WEI Xiaona, ZHANG Wei, and ZHUANG Songlin
Usually, freeform optical surfaces do not have rotational symmetry compared with traditional spherical and aspheric elements, so they have more freedom for system design. In some optical systems which have strict package requirements, such as overall length, weight and volume etc., freeform optical elements can help Usually, freeform optical surfaces do not have rotational symmetry compared with traditional spherical and aspheric elements, so they have more freedom for system design. In some optical systems which have strict package requirements, such as overall length, weight and volume etc., freeform optical elements can help to satisfy these requirements through reducing lens number of the system. In this paper, the design method of freeform optical elements was introduced, and proposed several design examples of the optical system were proposed which adopted freeform optical elements. From these design examples, the advantages of using freeform optical elements could be proved. The size of the microdisplay used is 0.61 inch and FOV is 45°. The exit pupil diameter is 10 mm..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1051 (2011)
Influence of Impurity on Radiative Properties of Randomly Oriented Cluster Agglomerates
LEI Chengxin, FENG Dongtai, and WU Zhensen
The influence of impurity on the radiative properties of randomly oriented cluster agglomerates was mainly analyzed. The equivalent complex refractive index of aerosols containing different volume fractions of amorphous carbon was obtained by Bruggeman effective medium theory. The radiative characteristic quantities weThe influence of impurity on the radiative properties of randomly oriented cluster agglomerates was mainly analyzed. The equivalent complex refractive index of aerosols containing different volume fractions of amorphous carbon was obtained by Bruggeman effective medium theory. The radiative characteristic quantities were calculated based on the discrete dipole approximation method, such as the phase function, extinction, absorption and scattering efficiency factor, singlescattering albedo and asymmetrical parameter of randomly oriented cluster agglomerates. The influence of the impurity on the radiative properties of randomly oriented cluster agglomerates was mainly discussed. The results indicate that the influence of the impurity on the radiative properties of randomly oriented cluster agglomerates is obvious, and it varies with the size parameters of the randomly distributed cluster agglomerates. This work is important for the study of radiative characteristics of aerosols with a mixture of various chemical compositions and their climatic effects..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1055 (2011)
Lighting Pattern of Underwater Optical Monitoring System
ZHANG Faquan, WANG Guofu, YE Jincai, LIU Qinghua, and CHEN Liangyi
A method to determine directional angle of light source and installation location was proposed. Using transmission characteristics of underwater rays of light and considering transmission distance, volume scattering function, scattering angle and the small volume unit, the illuminating effect of various directional angA method to determine directional angle of light source and installation location was proposed. Using transmission characteristics of underwater rays of light and considering transmission distance, volume scattering function, scattering angle and the small volume unit, the illuminating effect of various directional angle of the light source were analyzed. The selection principle of directional angle of the light source was proposed. It was that when meeting the requirements of the monitoring area, dirctional angle of the light source should be chosen to make the scattering angle maximum. When the view field angle was 45°, directional angle of the light source should be 67.5°. According to the boundary of the monitoring area and directional angle of the light source, the installation location of the light source was determined. The real results show that the system can meet the requirements of monitoring and has good effect..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1061 (2011)
SWBF Classification Based on BP Neural Network
CHANG Yang, CUI Hong, and ZHANG Jiansheng
A new method which classification of simulated wake bubble films（SWBF）can be obtained by using imaging processing methods. The paper introducts the basic structure and working principals of the BP neural network, the simulation tested classification of SWBF image based on BP neural network. The characteristic quantitieA new method which classification of simulated wake bubble films（SWBF）can be obtained by using imaging processing methods. The paper introducts the basic structure and working principals of the BP neural network, the simulation tested classification of SWBF image based on BP neural network. The characteristic quantities such as mean value,normalized coefficient,the third moment,uniformity, entropy can be extracted based on gray histogram statistical moment. After 14 epochs, training error can be reached 0.001 when we setting neural network learning rate is 0.1, while the classification accuracy can be up to 100% under different pressures on SWBF.The method has characteristics such as visibility, high efficiency and accuracy, and can be apt to applied in engineering projects for wakes′ detection and recognition..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1066 (2011)
Influence of Photonic Band Gap in Non uniform Plasma Photonic Crystals Induced by Compton Scattering
FENG Gang, GAO Lina, and HAO Dongshan
Using the model of the nonlinear Compton scattering and FDTD algorithm, influences on the photonic band gap characteristic of the uniform plasma photonic crystals were studied, induced by the multiphoton nonlinear Compton scattering. A new mechanism of photon band gap induced by incident light and scattered light was Using the model of the nonlinear Compton scattering and FDTD algorithm, influences on the photonic band gap characteristic of the uniform plasma photonic crystals were studied, induced by the multiphoton nonlinear Compton scattering. A new mechanism of photon band gap induced by incident light and scattered light was given out, and the electromagnetic wave equations were amended. The results show that attenuating of the electromagnetic wave peal value is faster after the Compton scattering, prohibit band gap widths of electromagnetic wave transmission chart nearly are not changed along with the increase of the plasma density, central frequencies are clearly moved to the high frequency directions, the upward crest values have bigger increase numbers, and the downward crest values of the reflected chart have bigger decrease numbers. The prohibit band gap widths of the transmission chart have clear decrease numbers along with the increases of the plasma temperature, the upward crest values have even little decrease numbers, and the transmission energy have littler decrease numbers too. The photon prohibit band gap numbers are increased along with the increases of the dielectric constant ratio value in the two mediums, and the band gap intervals are clearly decreased..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1071 (2011)
Polarization Bandpass Filters Based on Onedimensional Dielectric and Magnetic Photonic Crystals
DONG Qiuyun, MA Shuyun, WANG Hui, and QIANG Haixia
Onedimensional traditional pure dielectric photonic crystals have disadvantages that the design of TEpolarization bandpass filters is difficult, and the bandgaps of TE and TMpolarization bandpass filters are narrow. Based on the fact that a greater permittivity (permeability) than permeability (permittivity) makeOnedimensional traditional pure dielectric photonic crystals have disadvantages that the design of TEpolarization bandpass filters is difficult, and the bandgaps of TE and TMpolarization bandpass filters are narrow. Based on the fact that a greater permittivity (permeability) than permeability (permittivity) makes wider TE (TM) bands than TM (TE) bands, three kinds of filters, (TEpolarization bandpass filter, TMpolarization bandpass filter and doublepolarization bandpass filter), were designed by stopband superposition of onedimensional photonic crystals. Each of them was a heterostructure constructed by two subphotoniccrystals, hence the structure provided a narrowfrequency passband and the bandgap was enlarged. Due to the combination of dielectric and magnetic materials, the proposed design has simple structures with wide bandgaps and narrowfrequency passbands. Besides, the effect of magnetic material dispersion on the performance of polarization filters was discussed using a kind of magnetic material which has been reported..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1076 (2011)
Interaction for Bovine Serum Albumin with Fluorescent Whitening Agent by Fluorescence Spectroscopy
PAN Keliang, and LI Shukei
Interaction of bovine serum albumin(BSA) with fluorescent whitening agent(FWA) CBSX, BBU and VBL were studied by fluorescence spectrometry. The quenching mechanism of intrinsic fluorescence of BSA with FWAs were studied by Sternvolmer curve, LineweaverBurk curve and double reciprocal curve. The experimental results Interaction of bovine serum albumin(BSA) with fluorescent whitening agent(FWA) CBSX, BBU and VBL were studied by fluorescence spectrometry. The quenching mechanism of intrinsic fluorescence of BSA with FWAs were studied by Sternvolmer curve, LineweaverBurk curve and double reciprocal curve. The experimental results show that static quenching and fluorescence resonance energy transfer quenching are the main factors of the quenching mechanism of intrinsic fluorescence. The quenching constants and diffusion constants between BSA and FWAs(283 K) were measured, and all of the numbers of binding sites are 1. Based on the theory of Frster energy transfer spectroscopy, the binding distance r and the energy transfer efficiency between BSA and FWAs were obtained. The thermodynamic parameters of binding reactions were determined by the binding constants in 283K and 298K. All of the reaction enthalpies and the entropy were decreased. According to these, the interaction between BSA and FWAs were driven mainly by electrostatic force..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1082 (2011)
Spectral characteristics of Ba2B2P2O10∶Eu2+ green phosphor for white LED
WANG Zhijun, LI Panlai, GUO Qinglin, and YANG Zhiping
A novel green emitting phosphor, Ba2B2P2O10∶Eu2+, is prepared by solid state method, and its luminescent characteristics are investigated. BaCO3, H3BO3, NH4H2PO4 and Eu2O3 were used as starting materials. After these individual materials were blended and grounded thoroughly in an agate mortar, the homogeneous mixture wA novel green emitting phosphor, Ba2B2P2O10∶Eu2+, is prepared by solid state method, and its luminescent characteristics are investigated. BaCO3, H3BO3, NH4H2PO4 and Eu2O3 were used as starting materials. After these individual materials were blended and grounded thoroughly in an agate mortar, the homogeneous mixture was heated at 1 000 ℃ for 5 h in a reduce atmosphere (5:95(H2/N2)), and the phosphor were obtained. The phase present of the samples was characterized by powder Xray diffraction (XRD). The spectral characteristics of the phosphors were measured by a SHIMADZU RF540 fluorescence spectrophotometer. Ba2B2P2O10∶Eu2+ shows a one dissymmetrical band at 522 nm, and the excitation spectrum for 522 nm emission extends from 300 to 450 nm, and the highest peak locates at 381 nm. The crystallographic sites of Eu2+ in Ba2B2P2O10 were calculated by van Uitert formula. The result shows that 507 nm emission band originates from the eight sites of Eu2+, and that 542 nm emission band comes of the six sites of Eu2+. The effect of Eu2+ content on the emission intensity of Ba2B2P2O10∶Eu2+ phosphor was investigated, the result shows that the emission intensity of the phosphor increases with increasing Eu2+ concentration, then decreases, viz., the concentration quenching exists, and the Eu2+ concentration corresponding to the maximal emission intensity is 3 mol%. And the concentration quenching mechanism is the dd interaction..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1087 (2011)
Influence of SiO2 Nanoparticles to Fluorescence Spectra of EthanolRhodamine 6G Solutions
YANG Ailing, ZHAO Weina, YANG Yun, and YAO Chao
SiO2 nanoparticles with eight different concentrations were doped in the Rhodanmine 6Gethanol solutions(3×10－4 M and 1×10－4 M).The influence of SiO2 nanoparticles to the fluorescence spectra of R6Gethanol solutions were investigated. The results shows:1)when the concentrations of SiO2 within in the range ofSiO2 nanoparticles with eight different concentrations were doped in the Rhodanmine 6Gethanol solutions(3×10－4 M and 1×10－4 M).The influence of SiO2 nanoparticles to the fluorescence spectra of R6Gethanol solutions were investigated. The results shows:1)when the concentrations of SiO2 within in the range of n1～n4(1012～1010/mL), the fluorescence spectra at 549 nm were well enhanced, but the fluorescence peaks at 570 nm was obviously quenched and the peaks have a read shift; 2) when the concentrations of SiO2 within in the range of n5～n8(109~107/mL),the fluorescence spectra at 549 nm were not enhanced significantly, but the fluorescence peaks at 570 nm was obviously enhanced, the enhancement factors can get to 10%~20%, and the peaks do not have a red shift. The reasons of the fluorescence enhancing or quenching are relative to the scattering of the nanoparticles to the luminescence and the nonfluorescent Hdimers or fluorescent Jdimers of R6G moleculars..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1091 (2011)
Thickness and Optical Constants Calculation of Hydrogenated Amorphous Silicon Film Based on Transmission and Reflectance Spectra
DING Wenge, YUAN Jing, LI Wenbo, LI Bin, YU Wei, and FU Guangsheng
Hydrogenated amorphous silicon (aSi:H) films were deposited on quartz substrates by reactive facing target sputtering technique. The transmission and reflectance spectra of aSi:H thin films measured by UVVIS transmittance measurement were studied. The absorption coefficient α, therefore extinction coefficient κ, werHydrogenated amorphous silicon (aSi:H) films were deposited on quartz substrates by reactive facing target sputtering technique. The transmission and reflectance spectra of aSi:H thin films measured by UVVIS transmittance measurement were studied. The absorption coefficient α, therefore extinction coefficient κ, were determined by T/(1－R) method. The refractive index n and film average thickness d were determined from the upper and lower envelopes of the transmission spectra, and further modified by the basic equation for interference fringes. The dispersion curve of aSi:H film fitted by Cauchy dispersion relationship of refractive index was given. In order to illuminate the reliability of the determined parameters, the calculated transmission curve was compared to experimental one, the results show the two curves almost match together. Therefore the method is effective to determine aSi: H thin film thickness and optical constants..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1096 (2011)
Light Obstructing Effect of Liquid Membrane
MIAO Runcai, GAO Meiling, HAN Pengbin, and LI Nengneng
When a laser beam passes through the static liquid membrane, the light obstructing effect is observed due to surface total reflection. Based on this fact, the similar light obstructing effect was also observed using a white light source, and the obtained obstructed light photos were clear and with no laser speckles. ThWhen a laser beam passes through the static liquid membrane, the light obstructing effect is observed due to surface total reflection. Based on this fact, the similar light obstructing effect was also observed using a white light source, and the obtained obstructed light photos were clear and with no laser speckles. The obstructed light pattern consists of a bright region with significantly high light intensities in the center, two stripshape dark regions outside, and a bright field between these two stripshape dark regions. The boundaries between these bright and dark regions were clear. It was found that the radius of obstructing increases with the increasing of the refractive index. Moreover, the relationship between the liquid membrane refractive index and the radius of light obstructed was derived, and the necessary and sufficient conditions of the obstructed light photos for liquid membrane were also analyzed. Therefore, according to the effect of light obstructing of liquid membrane, a new method for measuring liquid refractive index was proposed. The refractive index of pure water was measured and the obtained results were good in line with those measured by the traditional methods. The proposed method has advantages in simplifying the equipments and operations, and also possesses sound reliabilities and high measuring accuracy..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1101 (2011)
Research on Remote Sensing Image Generation Modeling in the Visible Regions
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
This paper addresses the research of fidelity and flexibility of remote sensing image generation modeling and simulation, and presented a synthetic image generation model which deals spectrally with multifold effects base on a three dimension digtial geometric scene and raytracing render engine. At first this paper trThis paper addresses the research of fidelity and flexibility of remote sensing image generation modeling and simulation, and presented a synthetic image generation model which deals spectrally with multifold effects base on a three dimension digtial geometric scene and raytracing render engine. At first this paper tried to set up the imaging simulation system from the completeness and expansibility angle by stratifing and modularizing each important factor of whole imaging chain. In order to effectively utilize existing calculation model and able to interoperate for the new algorithm model, the call and communication relations between each module is designed by combining existing 3d technology, light tracing technology, sensor simulation technology. And the radiance calculation module, the ray tracing calculation module and sensor effect simulation module were discussed. Then aimed at a space scene simulation application. The model framework, submodels and spectral image examples achieved by C++ programming language are presented which can be widely use in sensor prototyping, algorithm testing , efficiency assessment at satellite design phase..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1106 (2011)
A Passive Ranging System Based on Image Sequence From Single Lens and the Respective Imaging Direction along with Its Performance
WANG Di, WANG Jie, and FU Xiaoning
Aiming at the passive ranging to a noncooperate target, a system based on image sequence from single lens and the respective imaging direction is introduced with its performance. This ranging system does not need initial distance guiding. The distance from target to camera can be estimated by solving a special rangingAiming at the passive ranging to a noncooperate target, a system based on image sequence from single lens and the respective imaging direction is introduced with its performance. This ranging system does not need initial distance guiding. The distance from target to camera can be estimated by solving a special ranging equation, which is made from target′s characteristic linearity, camera′s coordinates in space, and the target′s azimuth and pitching to the camera. Among these data, azimuth and pitching are obtained by an electrooptical altazimuth. Camera′s coordinates come from a GPS, and the target′s characteristic linearity will be from the image matching between adjacent frames in the image sequence. Analysis shows that the ranging error is mainly determined by the precision of the characteristic linearity, other influencing factors have less impact, which include the measurement error of the target′s azimuth or pitch and the error of the camera′ coordinates. Thus a linearity can be obtained by selecting three matched points in each adjacent frames. These three points have strong Scale Invariant Feature Transform characteristic, with the points a triangle and its circumcircle can be settled. The chord across barycenter of the triangle can be taken as the best characteristic linearity. The experimental result indicates that this ranging method can realize the passive ranging to a noncooperate big target..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1112 (2011)
Finite Element Method for ThreeOrder (P3) Approximation of Radiative Transfer Equation
MA Wenjuan, GAO Feng, ZHU Pingping, and YI Xi
The flux takes the form of an expansion in spherical harmonics, and the twodimensional spherical harmonics equations to threeorder for anisotropic scattering is drived. The equations is solved using finite element method and compared the solutions with the firstorder diffusion equation and Monte Carlo simulation. ThThe flux takes the form of an expansion in spherical harmonics, and the twodimensional spherical harmonics equations to threeorder for anisotropic scattering is drived. The equations is solved using finite element method and compared the solutions with the firstorder diffusion equation and Monte Carlo simulation. The resolut shows that the developed threeorder model with high absorb coefficient is able to significantly improve the diffusion solution in circle geometry, and the radiance distribution close to light source is more accurate..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1117 (2011)
Nonlinear Optical Properties of the “Green” Liquid Laser Medium
PENG Wenxuan, FENG Guoying, ZHANG Qiuhui, WU Aiming, LIU Kui, LI Mi, and SONG Yingsong
Using Nd2O3 and HCl as raw materials, Nd (phen)2Cl3 was obtained and its spectral characteristics were measured. With Nd2O3, benzoic acid and ophenanthroline as the raw material, green liquid laser medium Nd3+ ions complexes—NdB3phen (tribenzoic acidphenanthroline coNd) was prepared. The thirdorder nonlinear opticUsing Nd2O3 and HCl as raw materials, Nd (phen)2Cl3 was obtained and its spectral characteristics were measured. With Nd2O3, benzoic acid and ophenanthroline as the raw material, green liquid laser medium Nd3+ ions complexes—NdB3phen (tribenzoic acidphenanthroline coNd) was prepared. The thirdorder nonlinear optical properties of NdB3phen were studied using femtosecond laser and signalbeam Zscan method. When the incident femtosecond laser pulse wavelength is 400 nm, the peak power density is 2.94×1014 W/m2, and pulse width is 117 fs, the measured nonlinear refractiveindex coefficient of the sample is －2.84×10－15 cm2/W. Under the opening aperture configuration, NdB3phen presents phenomenon of the reverse saturated absorption, and the measured twophoton absorption coefficient is estimated to be 9.11×10－12 m/W. The experimental results show that twophoton absorption coefficient and nonlinear refractiveindex coefficient of NdB3phen refractive index become more intense..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 40, Issue 7, 1122 (2011)
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