Journals >Acta Photonica Sinica
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2015
Volume: 44 Issue 3
35 Article(s)
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Research Article
Simulation of the Rough Target′s Signal in Synthetic Aperture Ladar
DANG Wen-jia, ZENG Xiao-dong, CAO Chang-qing, LAI Zhi, FENG Zhe-jun, and LI Tian-tian
Based on Mente Carlo method, the modulating effect of the target surface roughness on the optical heterodyne signal was discussed. The quantitative analysis of the decoherence effect caused by the roughness of targets was investigated. The relationship between the optical heterodyne signal and rough parameters of the tBased on Mente Carlo method, the modulating effect of the target surface roughness on the optical heterodyne signal was discussed. The quantitative analysis of the decoherence effect caused by the roughness of targets was investigated. The relationship between the optical heterodyne signal and rough parameters of the target was given. It is shown that when the correlation length is 100λ, the optical heterodyne signal increases with the height of the root mean square fluctuation decreasing. When the height of the root mean square fluctuation exceeds 0.2λ, the optical heterodyne signal is very weak. In addition, when the height of the root mean square is 0.1λ, the optical heterodyne signal decreases with the correlation length decreasing. It seriously affects the optical heterodyne detection of a rough target..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 304001 (2015)
Seasonal Requirement of the Infrared Camouflage Paint′s Emissivity
HE Zi-jian, SHI Jia-ming, WANG Jia-chun, YUAN Zhong-cai, ZHAO Da-peng, LIN Zhi-dan, and FENG Yue-yue
To analyses the seasonal requirement of camouflage paint′s average emissivity in 8-14 μm waveband, after simulating the change of the solar radiation, the vegetative cover′s temperature and the air temperature in one day, a temperature model of target and vegetative cover that display the changing of their radiation teTo analyses the seasonal requirement of camouflage paint′s average emissivity in 8-14 μm waveband, after simulating the change of the solar radiation, the vegetative cover′s temperature and the air temperature in one day, a temperature model of target and vegetative cover that display the changing of their radiation temperature in one day of different seasons was built.Hefei as an example, represent four seasons′ climate by the weather conditions of spring equinox, summer solstice, autumnal equinox and winter solstice and collect Hefei′s climate data of these solar terms in recent five years.Imitated the radiation temperature of target that covered the camouflage paint with different average emissivity in 8-14 μm waveband and vegetative cover from 6 to 22 in these solar terms.The Euclid Distance and the camouflage efficiency were obtained by the radiation temperature data to analyze the camouflage effect.When the Euclid Distance is least the infrared characteristic of target is closest to the vegetative cover′s.In this condition, the emissivities in different seasons are 0.58, 0.33, 0.41 and 0.86.Radiation temperature difference between target and background within 4K is the standard to achieve stealth.Reference this standard, the target has the best camouflage efficiency in different seasons when the emissivities are 0.6, 0.3, 0.4 and 0.9..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 304002 (2015)
Applied Research of Dual-wavelength Shearography for Flaw Detection of Composite Material
GUO Yuan, MAO Qi, CHENG Xiao-tian, WU Quan, and ZHEN Wei
A color CCD camera are adopted to make sure shearography can be applied in large deformation of objects dual-wavelength lasers illumination. By separating the spectrum in the Fourier domain, the subtraction of the red wavelength phase and the green wavelength phase yielded a new phase distribution of a synthetic waveleA color CCD camera are adopted to make sure shearography can be applied in large deformation of objects dual-wavelength lasers illumination. By separating the spectrum in the Fourier domain, the subtraction of the red wavelength phase and the green wavelength phase yielded a new phase distribution of a synthetic wavelength. After filtering in frequency domain and phase unwrapping, the continuous phase can be gotten. The number of phase stripes of synthetic wavelength is 0.189 times smaller than that of single wavelength by theoretical derivation. Using the synthetic wavelength can reduce the phase fringe density effectively, and solve the sub-Nyquist sampling problem, which are caused by too intensive interference fringes in object′s deformation. In addition, it also reduces the difficulty of image processing in filtering and phase unwrapping, enhances the reliability of image processing, and improves the measurement accuracy. Phase comparing between synthetic wavelength and single wavelength were given. Moreover, the fringe densities of the two kinds of wavelengths at the same external force also were compared. Experiments verify the effective, accuracy, and reliable of this method. It can process the large deformation measurement of composite material and dramatically expand the measurement rang of shearography in engineering application. It also provides a reference for the designing new type system of shearography..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 312001 (2015)
Selection of Sampling Points in Two Dimensional Lateral Shearing Interferometry
WANG Hong-jun, ZHANG Cong, TIAN Ai-ling, and LIU Bing-cai
To realize the widely use of phase shift type lateralshearing interferometer in large-diameter aspherical online detection, the measuring for aspherical surface by lateral shearing interferometer was simulated to reconstruct the two dimensional surface. Shearing displacement size and sampling points numbers in the x anTo realize the widely use of phase shift type lateralshearing interferometer in large-diameter aspherical online detection, the measuring for aspherical surface by lateral shearing interferometer was simulated to reconstruct the two dimensional surface. Shearing displacement size and sampling points numbers in the x and y direction of simulated aspheric surfaces were analysed, respectively. By using least squares method to strike waves difference and Zernike polynomial quasi to reconstruct wave-front, a non-spherical surface was simulated. The results indicate that, it′s suitable to set the shearing amount of one-tenth about the size of the aperture to guarantee high precision, and only 49 discrete sampling points are needed to display the two dimensional surface topography by using Zernike polynomial fitting.The conclusion provides a theoretical guidance for the phase shift type two-dimensional wavefront reconstruction of lateral shearing interferometry and technical support for the online practical application of large-diameter aspherical surface measurement..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 312002 (2015)
Research on Generating Device of Infinite Low Light Level Weapon Sight Target Simulation
XIAO Zuo-jiang, GUO Xiao-xue, ZHU Hai-bin, XU Zhi-gang, and AN Zhi-yong
According to scene illumination under night sky radiation, when shooters were aiming and positioning at night, the illumination at the entrance pupil of the sight was calculated, and the generating device for infinite target simulation based on double-integrating-sphere in illumination-mode was designed in accordance wAccording to scene illumination under night sky radiation, when shooters were aiming and positioning at night, the illumination at the entrance pupil of the sight was calculated, and the generating device for infinite target simulation based on double-integrating-sphere in illumination-mode was designed in accordance with the illumination. Variable diaphragm applied to offer four switchable low light stress environments for the night vision device according to the principle of the integrating sphere, which was setting between the double-integrating-sphere. Meanwhile, for the sake of the maximum illumination could be received by the Low-Light-Level sight during the test, the installation position of the sight relative to collimator was analyzed. The results show that the three crucial factors which influenced the illumination at its entrance pupil are scilicet the clear aperture of the iris diaphragm setting between the double-integrating-sphere, the field of view of the collimator, and the installation position of the Low-Light-Level weapon sight apart from the collimator objective. Finally, the output illuminance of the integrating sphere and generating device were analyzed and calculated, the results of experiment and measuring showed that the illumination non-uniformity is<2%, which can meet the application requirements..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 312003 (2015)
Achromatism about Negative Refractive Index Lens
ZHANG Bo, CUI Qing-feng, XUE Chang-xi, PIAO Ming-xu, and YU Chun-yan
An example of achromatic designs for a negative-refractive-index plane-concave lens with 100 mm focal length, 20 mm the pupil diameter and negative abbe number in near infrared wave band from 0.848 μm to 1.114 μm was given to explain two achromatic methods about the negative-refractive-index lens.The two methods are coAn example of achromatic designs for a negative-refractive-index plane-concave lens with 100 mm focal length, 20 mm the pupil diameter and negative abbe number in near infrared wave band from 0.848 μm to 1.114 μm was given to explain two achromatic methods about the negative-refractive-index lens.The two methods are combing positive-refractive-index lens with negative-refractive-index lens and introducing the diffractive optical elements into the negative-refractive-index lens.The analysis results show that the positive-refractive-index lens undertakes almost all the power in the method of combing positive-refractive-index lens with negative-refractive-index lens, so a large number of additional monochromatic aberrations are introduced.However, the diffraction optical element can correct the chromatic-aberration of the negative-refractive-index lens without introducing additional aberrations.The diffraction efficiency of the negative-refractive-index diffractive optical elements is deduced based on the special propagating laws and imaging properties of negative-index lenses, the expression for microstructure height is given, and the diffraction efficiencies are calculated.The diffraction efficiency for the negative-index binary diffractive optical element in the design wavelength 0.912 μm is 40.53%, in wavelength 0.848 μm is 35.06%, and in wavelength 1.114 μm is 39.83%..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 312004 (2015)
Characteristic Analysis of Noise Factor in the Periodic Stripe Long Range Surface Plasmon Polaritons Structure
LI Zhi-quan, YAN Lei, GUO Jia-liang, ZHU Jun, and ZHAO Ling-ling
Through the noise factor theory of amplified spontaneous emission of Surface Plasmon Polaritons (SPPs), the variations of noise factor of Long Range Surface Plasmon Polaritons(LRSPPs) were studied.And a waveguide structure with strips embedded in the metal film of LRSPPs structure is designed.Numerical simulation is usThrough the noise factor theory of amplified spontaneous emission of Surface Plasmon Polaritons (SPPs), the variations of noise factor of Long Range Surface Plasmon Polaritons(LRSPPs) were studied.And a waveguide structure with strips embedded in the metal film of LRSPPs structure is designed.Numerical simulation is used to get the noise factor variations of SPPs and LRSPPs.In the numerical simulation, incident wavelength ranges from 0.5 μm to 1.75 μm, and check the characteristics of noise factors for every 0.25 μm, the results show that the noise factors approach to a constant value with the increase of wavelength.The simulation results show that the noise factor of the amplified spontaneous emission of the SPPs and the LRSPPs are enhanced apparently with the increase of grain mediums;noise factors of periodic stripe LRSPPs are increased as the thicknesses of metal film and the height and the number metal strip are increased, where the impact of the thickness of metal film is relatively evident..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 319001 (2015)
Brillouin Scattering Parameters of Different Modes in Multimode Optical Fibers
LI Yong-qian, ZHAO Xu, ZHAO Li-juan, MA Li, LI Xiao-juan, and AN Qi
The characteristics of Brillouin scattering in silica multimode optial fiber were analyzed based on the ray optics and wave optics theory.A method to determine the range of Brillouin scattering angle was proposed and the expressions of Brillouin shift, Brillouin linewidth, Brillouin scattering spectrum and scattering pThe characteristics of Brillouin scattering in silica multimode optial fiber were analyzed based on the ray optics and wave optics theory.A method to determine the range of Brillouin scattering angle was proposed and the expressions of Brillouin shift, Brillouin linewidth, Brillouin scattering spectrum and scattering power of different mode group in step and graded multimode optical fibers are deduced and simulated.The results show that the maximum range of Brillouin scattering angle in step and graded fibers is from twice of the critical incident angle of total reflection to π, and with the increasing of mode group number, Brillouin shift, Brillouin linewidth, normalized peak gain and scattering power of step fiber change more slowly than those of graded fiber, and the above parameters of step fiber decrease nonlinearly in the ranges of 11.084 GHz to 10.932 GHz, 21.760 MHz to 21.168 MHz, 1 to 0.933 and 1.990×10-9 W to 1.857×10-9 W, but the correspending parameters of graded fiber decrease linearly in the ranges of 11.064 GHz to 10.969 GHz, 21.683 MHz to 21.314 MHz, 1 to 0.957 and 2.052×10-9 W to 1.965×10-9 W, respectively..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 319002 (2015)
Research on Comparison of Intelligent Optimization Algorithms in the Parameters Retrieval of Crystal Dispersion Equation
WANG An-xiang, ZHU Chang-jun, and ZHANG Xiao-jun
In order to study iteration searching properties of intelligent optimization algorithms parameters in dispersion equations of different crystal material, genetic algorithm, simulated annealing algorithm and genetic simulated annealing algorithm were employed, respectively, to obtain the coefficients of the improved SelIn order to study iteration searching properties of intelligent optimization algorithms parameters in dispersion equations of different crystal material, genetic algorithm, simulated annealing algorithm and genetic simulated annealing algorithm were employed, respectively, to obtain the coefficients of the improved Sellmeier equation for quartz crystal and calcite crystal according to the measured experimental data.Meanwhile, the differences of iteration searching property, algorithm stability, computation time and sum of squares of deviations in the three algorithms were compared.The results show that the three algorithms are all feasible in terms of coefficients retrieval in the dispersion equation, however, genetic simulated annealing algorithm have rapid large-scale search and strong local search performance deriving from the genetic algorithm and simulated annealing algorithm respectively.It makes optimization results of crystal dispersion equation parameters in inversion to be better.Therefore, we recommend using the genetic simulated annealing algorithm to obtain dispersion equations for other materials.The aforementioned results are of help to the study of iteration searching properties of mixed intelligent algorithms..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 319003 (2015)
Reflection Band Gap in Thue-Morse Quasicrystal Containing Anisotropic Left Handed Material
KANG Yong-qiang, GAO Peng, LIU Hong-mei, and ZHANG Chun-min
By means of transfer matrix method, the reflection band gap of Thue-Morse(T-M) structure containing anisotropic left handed material was studied.The influence of incident angle, polarization and lattice scaling factor on reflection band gap was theoretically investigated.It is shown that there is an Omnidirectional RefBy means of transfer matrix method, the reflection band gap of Thue-Morse(T-M) structure containing anisotropic left handed material was studied.The influence of incident angle, polarization and lattice scaling factor on reflection band gap was theoretically investigated.It is shown that there is an Omnidirectional Reflection Band (ORB) in the structure.The width of the ORB is determined by the higher frequency band edge for TE polarization and the lower frequency band edge for TM polarization.When an impurity is introduced, a defect mode appears in the reflection band gap.The position of the defect modes is weakly dependent on incident angle for TE polarization, but affected by incident angle for TM polarization..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 319004 (2015)
Scattering Spectra of Gold Nanorods Trapped by a Single Laser Beam
DENG Hai-dong, LI Hai, and GUO Zi-zheng
Two dimensional optical trapping of gold nanorods suspended in aqueous solution was investigated by using a single focused laser beam and the interaction between two gold nanorods was studied by measuring the scattering of gold nanorods trapped in the optical trap with a dark-field microscopy.It was found that the two Two dimensional optical trapping of gold nanorods suspended in aqueous solution was investigated by using a single focused laser beam and the interaction between two gold nanorods was studied by measuring the scattering of gold nanorods trapped in the optical trap with a dark-field microscopy.It was found that the two gold nanorods simultaneously trapped would keep certain distance due to the repulsive interaction, which suppressed the localized surface plasmonic coupling between the two gold nanorods.The experimental results will provide technological and experimental references for the optical trapping of gold nanorods and their application in the probing of biomolecules..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 329001 (2015)
Light Scattering Properties of Semitransparent Coatings on Rough Substrate Based on Surface Generation Method
LV Yi, GAO Jun, WANG Ling-mei, and WANG Chi
For the scattering process of light through the two rough surfaces consisted of semitransparent coatings and rough substrate, considering the shading effect and multiple scattering, Monte Carlo model of surface scattering was established based on surface generation method.The reflected light distribution of the semitraFor the scattering process of light through the two rough surfaces consisted of semitransparent coatings and rough substrate, considering the shading effect and multiple scattering, Monte Carlo model of surface scattering was established based on surface generation method.The reflected light distribution of the semitransparent coatings on rough substrate was obtained.The effects of coatings thickness, surface roughness and incident light wavelength on Bidirectional Reflectance Distribution Function (BRDF) were studied.Simulation results show that BRDF is largely affected by surface roughness, and the reflection peak decreases linearly with the root-mean-square slope of the surface.The semitransparent coatings thickness changes the value of BRDF.When the thickness is equal to one-tenth of the wavelength, BRDF reaches the minimum value.The local distribution of BRDF in the specular reflection direction with near-infrared light illumination tends to broaden up in comparison with visible light illumination, and the directional hemispherical reflectance with near-infrared light illumination is also larger..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 329002 (2015)
Study and Fabrication of Broad Band-pass Filters in Infrared Therapy Apparatus
LIU Dong-mei, LIU Shuang, FU Xiu-hua, ZHANG Jing, and HE Song-lin
Design and manufacture of a new type of filters which meet the infrared therapy apparatus needs. By selectively filtering for the light of the infrared light emitted by the therapy apparatus, reducing the portion of the band light carrier energy, improving the safety performance of the therapy apparatus. Based on the uDesign and manufacture of a new type of filters which meet the infrared therapy apparatus needs. By selectively filtering for the light of the infrared light emitted by the therapy apparatus, reducing the portion of the band light carrier energy, improving the safety performance of the therapy apparatus. Based on the use requirements of the filters to infrared therapy apparatus, chose Ti3O5 and SiO2 as high and low refractive index materials respectively. Thin films were prepared through electron beam evaporation method and ion-assisted deposition technique, and the thickness of the filter was controlled using crystal-controlled.By repeatedly optimizing technical parameters, the band-pass filter was prepared. The average transmittance of the filter is higher than 92% at the band of 600-1200nm, the average transmittance of the broad band-pass filter is less than 2% at the band of 300-550nm and1270nm-2000nm. To solve the problem of the single sided film was too thick to prepared. Based on the concept of splitting technical requirements, the double-sided of the color filter were coated. The results show that the difficulty of preparation are reduced, and filters can be easily manufactured in a large scale, the filter meets the actual requirements..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 331001 (2015)
Design and Fabrication of a Broad Spectrum and Wide Angle Beam Splitter in Smart Glasses Imaging System
FU Xiu-hua, ZHANG Yu-shuai, KOU Yang, LI Xu-na, LIU Dong-mei, ZHANG Jing, and LI Guang-hui
Based on the optical film theory, the membrane system was introduced to optimize the evaluation function, and the TFC software was used to optimize the membrane system, so that a 0°to 75°wide spectrum of P-polarized light beam splitter was designed. In order to produce the beam splitter, H4 and MgF2 were chosBased on the optical film theory, the membrane system was introduced to optimize the evaluation function, and the TFC software was used to optimize the membrane system, so that a 0°to 75°wide spectrum of P-polarized light beam splitter was designed. In order to produce the beam splitter, H4 and MgF2 were chosen as high/low refractive index materials, and the electron beam and ion assisted deposition techniques were adopted. During the experiment, the film thickness error was analyzed and a crystal was used to control the highly sensitive layers, which solved the accuracy problem in the film preparation process. Utilizing the inverse analysis method to simulate the experimental results, the P-polarized light transmission spectrum curves become smoother by changing the thickness of the correction factor. The spectral testing shows that the average transmittance of the prepared beam filter is 60.3% with vertical incidence P-polarized light, which meets the requirements of the system..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 331002 (2015)
Effect of Preforming Pressure to Precursor on the Property of Exfoliated Graphite
MA De-yue, LI Xiao-xia, GUO Yu-xiang, and ZHAO Ji-jin
In order to make better use of exfoliated graphite in electro-optical countermeasure, the micro-morphology and expanding volume of preformed precursors and the infrared extinction of exfoliated graphite exfoliated from the precursors were researched, respectively.First, the micro-morphology of precursors preformed at dIn order to make better use of exfoliated graphite in electro-optical countermeasure, the micro-morphology and expanding volume of preformed precursors and the infrared extinction of exfoliated graphite exfoliated from the precursors were researched, respectively.First, the micro-morphology of precursors preformed at different pressure were analyzed by scanning electron microscope, and the morphology of exfoliated graphite from preformed precursors were observed by a stereomicroscope; Then, the expanding volume of the preformed precursors were tested; Finally, the infrared extinction of exfoliated graphite exfoliated from the preformed precursors was measured and analyzed.Experimental results indicate that the scales and layer of the preformed precursors is bended, distorted and fragmented, the opened interlayer spacing becomes shorter, and its intercalated structure is destroyed.As the preforming pressure is increasing, the expanding volume of the preformed precursors decreases from 356 mL/g to 216 mL/g, while correspondingly the infrared screening rate of exfoliated graphite obtained from above precursors decreases from 0.87 to 0.42.Therefore, the micro-morphology of the preformed precursors is destroyed seriously due to performing pressure, and its expanding volume and infrared-extinction of exfoliated graphite exfoliating from the corresponding precursors decrease continually with the increasing of preforming pressure..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 331003 (2015)
Fiber Optics and Optical Communications
Spreading and Wander of Partially Coherent Beam through Atmospheric Turbulence in a Slanted Path
KE Xi-zheng, HAN Mei-miao, and WANG Ming-jun
Based on the the general expression of the beam wander variance modeled by Andrews and Philips, the expression of wander variance for partially coherent Gaussian-Schell model beam considering the outer scale was derived using beam width formula of partially coherent Gaussian-Schell model beam propagating in slanted atmBased on the the general expression of the beam wander variance modeled by Andrews and Philips, the expression of wander variance for partially coherent Gaussian-Schell model beam considering the outer scale was derived using beam width formula of partially coherent Gaussian-Schell model beam propagating in slanted atmospheric turbulence, combining the turbulence structure constant model varying with height, numerical calculations were conducted and the spreading and wander variance of partially coherent beam and fully coherent beam were comparatively analyzed. The results show that, compared to the fully coherent beam, the partially coherent beam spreads faster and is less affected by turbulence under the same propagation conditions, and the beam spreading effect becomes weaker as the initial beam radius becomes larger or the height of the receiver becomes higher. As the propagation distance increases, the beam wander variance decreases with the increase of initial beam radius, the beam wander variance caused by different coherence have little difference. The wander of fully coherent beam is less affected by the wavelength, while the longer the wavelength of the partially coherent beam, the more obviously the beam wanders..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 306001 (2015)
Optical Fiber Bragg Grating Sensor Using Cantilever Beam of Qual Strength for Slope Sliding Displacement Monitoring
GAO Chao, LIU Bang, GUO Yong-cai, and ZHU Zheng-wei
A shear displacement sensoring device for monitoring rock sliding based on the principle of optical fiber Bragg grating.The displacement sensor was designed by attaching the fiber grating to equal strength cantilevers.Then the sensor was embedded inside a Φ50 polyvinyl chloride (PVC) tube.Three test models were made usA shear displacement sensoring device for monitoring rock sliding based on the principle of optical fiber Bragg grating.The displacement sensor was designed by attaching the fiber grating to equal strength cantilevers.Then the sensor was embedded inside a Φ50 polyvinyl chloride (PVC) tube.Three test models were made using Φ75 PVC tube with the Φ50 PVC tube mentioned before in it.Cement mortar was grouted into the gap between the Φ50 and Φ75 PVC tubes as ratio at 1: 1.Indoor shearing tests on the models were carried out.The curve of the relationship between the sliding distance and the grating wavelength shift was also measured.Results show that the sensitivity of this sensor is 0.5 mm and the maximal sliding distance could reach 30 mm while the grating wavelength could shift up to 1200 pm, of which indicates that the sensor could be well applied into sliding displacement measurement which needs a very high sensitivity.It is proved that the features of the fiber Bragg grating (FBG) sensor we designed are more sensitive and reliable, better anti-interference ability and larger measurement range.The structure of the sensor is simple, and it also can realize remote, real-time monitoring.Thus, the sensor can be used for landslide early warning monitoring..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 306002 (2015)
Design and Performance of a Low-loss Chalcogenide Hollow-core Photonic Crystal Fiber at 4.3 μm
DONG Yang-jian, DAI Shi-xun, ZHANG Pei-qing, LIU Yong-xing, YANG Pei-long, and WANG Xun-si
The band-gap maps of As2S3, Ge20Se65Sb15 and As2Se3 chalcogenide glass fibers at different air-fillings were analyzed by using the plane wave expansion method,. The results show that when increased to 0.75, the photonic band gap and air lines have appeared intersection mode, the band gap is wide, and an appropriate lasThe band-gap maps of As2S3, Ge20Se65Sb15 and As2Se3 chalcogenide glass fibers at different air-fillings were analyzed by using the plane wave expansion method,. The results show that when increased to 0.75, the photonic band gap and air lines have appeared intersection mode, the band gap is wide, and an appropriate laser transmission mode in the core of fiber is formed. Under different fiber core diameter, using the finite element method, the fundamental mode confinement loss and effective mode area of homemade Ge20Se65Sb15chalcogenide glass hollow-core photonic crystal fiber were systematically studied. The results show that the confinement loss is the lowest and the effective mode-field area is very small when the core diameter is 9.2 μm. By optimizing the structural parameters of fiber, a hollow-core photonic crystal fiber with low confinement loss (0.00472 dB/m) and effective mode-field area (58.046 μm2) at 4.3 μm was obtained..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 306003 (2015)
Optical Receiving Antenna for Indoor Visible Light Communication Based on Holographic Mirror
WANG Long-hui, LAN Tian, SHEN Zhen-min, LI Xiang, and NI Guo-qiang
A novel method for the design and production of the optical receiving antenna was proposed. The hologram called Holographic Mirror, which has the dual function of gathering beam and filtering ambient wave, is made from holographic material by using the principle of interference and diffraction. The angular selectivity,A novel method for the design and production of the optical receiving antenna was proposed. The hologram called Holographic Mirror, which has the dual function of gathering beam and filtering ambient wave, is made from holographic material by using the principle of interference and diffraction. The angular selectivity, spectral selectivity and diffraction efficiency at any point of the novel optical receiving antenna have been analyzed by coupled wave theory and k vector closed legitimate, the results of simulation show that the field of view and spectral bandwidth at different points of the Holographic Mirror are 0.8°-13.4° and 4.4 nm-7.4 nm respectively, and the overall diffraction efficiency of more than 95.3%. Compared with the combination of a converging lens and a filter into the conventional optical receiving antenna, small size, light weight, and low cost of the holographic mirror can be used as optical receiving antenna for indoor visible light communication..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 306004 (2015)
Output Characteristics of Bidirectional Feedback Brillouin-Raman Fiber Laser
MA Wan-zhuo, WANG Tian-shu, ZHANG Peng, ZHAO Chun-ying, ZHANG Jing, LIU Xin, KONG Mei, and JIANG Hui-lin
The output characteristic of a new-designed bidirectional feedback Brillouin-Raman fiber with Brillouin pump variation was studied.The Brillouin-Raman fiber laser consists of a segment of 7 km long dispersion compensating fiber, 1455 nm Raman pump, tunable laser and double feedback loops.The BP wavelength must be closeThe output characteristic of a new-designed bidirectional feedback Brillouin-Raman fiber with Brillouin pump variation was studied.The Brillouin-Raman fiber laser consists of a segment of 7 km long dispersion compensating fiber, 1455 nm Raman pump, tunable laser and double feedback loops.The BP wavelength must be closer to Raman peak gain to obtain more Stokes lines when RP is fixed at 250 mW.The power difference between the neighbouring Brillouin components and Rayleigh components was reduced by enhancing the BP power, the average intensity of Stokes lines was improved to the saturation value, simultaneously.Affected by the cross-gain in DCF, firstly the number of output lasing lines increase and then decrease when the BP power was adjusted from 1.8 dBm to 6.9 dBm.Maximum 37 output channels was obtained when BP power fixed at 4.4 dBm, the channel spacing is 0.078 nm..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 306005 (2015)
Holography
A Method to Improve Fringe Contrast in Time-average Digital Holography for Vibration Measurement
XIAO Wen, ZHANG Xu-hong, PAN Feng, CONG Lin, and LI Yan
A new algorithm was proposed to improve vibration-related fringes contrast for micro-vibration online detection based on time-average digital holography. First, phase change arising from the longitudinal micro-displacement of the object during vibrating process was corrected. Then phase noise caused by speckle noise waA new algorithm was proposed to improve vibration-related fringes contrast for micro-vibration online detection based on time-average digital holography. First, phase change arising from the longitudinal micro-displacement of the object during vibrating process was corrected. Then phase noise caused by speckle noise was eliminated, and thus fringes pattern contrast that modulated by Bessel function was improved effectively. Finally, the amplitude distribution of the measuring surface was estimated according to Bessel function and fringe progressions. An experimental system based on time-average digital holographic interferometry was proposed for micro-vibration measurement that acoustic wave was used for excitation source. The experiment was verified by the reed that excited at the sinusoidal frequency of 0, 1 100, 2 000 and 9 000 Hz, respectively. The result based on vibration frequency of 2 000 Hz shows that the proposed method can improve vibration-related fringes contrast effectively. Amplitude of three-order zero points are 109.4 nm, 244.2 nm and 356.4 nm, and errors are 6.31%, 3.34% and 3.78%, respectively, compared with theoretical values, which demonstrate the effectiveness of the method within the allowable range..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 309001 (2015)
New Methods of Removing Background and Applications in In-line Digital Holography
WU Xiu-pin, and GAO Wan-rong
Background decrease method and adaptive filtering methods were proposed to solve the background removing problem in digital holographic microscopy in the in-line digital holographic microscopy.In-line digital holography microscopic system was set up, with which the digital holographic images of onion epidermis, the plaBackground decrease method and adaptive filtering methods were proposed to solve the background removing problem in digital holographic microscopy in the in-line digital holographic microscopy.In-line digital holography microscopic system was set up, with which the digital holographic images of onion epidermis, the plant roots′ sample, the lamina stoma sample and the blood cell sample were reconstructed, respectively.In addition, the advantages of the proposed methods were demonstrated by calculating the light intensity distribution curves and the values of the contrast of images obtained with the in-line digital holographic microscope device.The results show that the backgrounds in the measured holographic interferometric fringes change with the experimental conditions and the sample itself.So that the backgrounds could be divided into three types, for each of which an appropriate method was proposed to achieve the best reconstruction image quality.The results may be helpful for reconstructing the better quality images..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 309002 (2015)
Design of Waveguide Holographic Configuration for Display
LIU Yu-jie, DING Quan-xin, LI Wen-qiang, and YAN Zhan-jun
In a holographic waveguide display system, the inconformity of grating parameters of input grating, turning grating and output leads to a lot of difficulties in system design and gratings fabrication process. The main condition that the turning grating should be in 60° conical mounting, on which all the gratings iIn a holographic waveguide display system, the inconformity of grating parameters of input grating, turning grating and output leads to a lot of difficulties in system design and gratings fabrication process. The main condition that the turning grating should be in 60° conical mounting, on which all the gratings in a waveguide holographic display configuration have uniform grating periods, was presented by comparing the grating equations in normal mounting and conical mounting. Under this condition, a novel efficient display was proposed by using a waveguide holographic configuration with three holographic gratings of the same grating periods recorded on a single substrate and a reflector placed on the side face of the substrate. The validity of this configuration was proved by the simulation carried out by the optical design software CODE V. The coupling efficiency loss and invalid area can be dramatically reduced by the reflector on the side face, compared with the traditional configuration. Moreover, the complexity of system design and holographic manufacture can be decreased because all gratings used in the proposed design have uniform grating periods and two of them have uniform orientation. The configuration can be applied to virtual reality display or wearable display..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 309003 (2015)
Imaging Systems
Infrared Image Sequence Complexity Analysis Based on Multi-attribute Decision Making
QIAO Li-yong, XU Li-xin, and GAO Min
To analyse the influences of infrared sequence complexity on the target tracking performance, the infrared sequence complexity evaluation had been modeled as a multi-attribute decision making problem. The each frame complexity of the infrared sequence had been evaluated with seven image metrics based on the modified teTo analyse the influences of infrared sequence complexity on the target tracking performance, the infrared sequence complexity evaluation had been modeled as a multi-attribute decision making problem. The each frame complexity of the infrared sequence had been evaluated with seven image metrics based on the modified technique for order preference by similarity to ideal solution method and entropy weights. The whole infrared image sequence complexity had been evaluated with three metrics based on weighted summation method and entropy weights. The normalized correlation template matching algorithm, basic mean shift algorithm, and the variance ratio algorithm had been used to implement tracking experiments. Infrared sequences with different complexity had beed used to validate the effectiveness of the presented infrared sequence evaluation method. The experiments showed that: the proposed infrared sequence complexity evaluation solution could truly indicate the differences of the tracking task difficulties for diverse infrared sequences, there was strong correlation with the tracking performance, and could accurately reflect the major influencing factors for target tracking task..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 311001 (2015)
Optical System Design of Multispectral Space Camera
LI Xu-yang, YI Hong-wei, and QI Hao-cheng
The reflective optical system which is characterized by the spectrum band 450-900 nm, focal length of 5 000 mm and F number of 10 was designed.The result indicates that the field angle reaches 1.6°, optical system distortion is less than 0.5%.Modulation Transfer Function (MTF) reaches 0.65 at Nyquist frequency(25 The reflective optical system which is characterized by the spectrum band 450-900 nm, focal length of 5 000 mm and F number of 10 was designed.The result indicates that the field angle reaches 1.6°, optical system distortion is less than 0.5%.Modulation Transfer Function (MTF) reaches 0.65 at Nyquist frequency(25 lp/mm) with 6% central obscure, the quality of image reaches the diffraction limited.At the same time, the paper studies the static MTF of all spectrums based on using time delayed integration CCD.So this kind of optical system can meet the demand for the use of multispectral space cameras..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 311002 (2015)
Separable Compressive Imaging with Deterministic Matrices
ZHANG Cheng, CHENG Hong, ZHANG Fen, and WEI Sui
Aiming at the heavy difficulty or high cost for the random orthogonal matrix which used in separable compressive sensing for high-dimensional signals sensing, such as large-scale image compressive reconstruction, deterministic measurement matrices was introduced, and a separable compressive sensing using deterministic Aiming at the heavy difficulty or high cost for the random orthogonal matrix which used in separable compressive sensing for high-dimensional signals sensing, such as large-scale image compressive reconstruction, deterministic measurement matrices was introduced, and a separable compressive sensing using deterministic matrices was proposed, matrix with deterministic structure, such as Toeplitz or Circulant matrix, could be used as a left/right separable matrix in separable compressed sensing. The proposed scheme can significantly reduce the number of independent elements, thus significantly reduce the difficulty and the cost of physical implementation. Numerical simulations evaluated comparisons of reconstruction performance of the proposed method with different downsampling rates and different image sizes. The results indicate that the proposed method can achieve similar reconstruction quality with far fewer independent elements as random orthogonal matrix′s, which demonstrates the feasibility of the proposed method..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 311003 (2015)
Point Spread Function of Pinhole Imaging System for Deviating from Center of Incident γ-Ray
MA Qing-li, TANG Shi-biao, and WU Yan-hua
The Point Spread Function(PSF) of a pinhole imaging system for γ-Ray has been studied through Monte Carlo method.The PSFs under 0, 0.5, 1, 1.5 and 2 pixel bias five different conditions have been obtained and analyzed by fitting the simulating data with Gauss function, the corresponding Modulation Transfer Function(MTFThe Point Spread Function(PSF) of a pinhole imaging system for γ-Ray has been studied through Monte Carlo method.The PSFs under 0, 0.5, 1, 1.5 and 2 pixel bias five different conditions have been obtained and analyzed by fitting the simulating data with Gauss function, the corresponding Modulation Transfer Function(MTF) can be obtained, and the spatial resolutions under these five conditions are compared.As the results show, when the excursion is little, the PSF′ deviation obtained by Gauss function fitting will be less and can meet the requirement of accuracy, but when the excursion is larger, the fitting deviation will be more. In addition, a ideal baffle between pinhole and detector will reduce the error and improve the spatial resolution remarkably..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 311004 (2015)
Optical Device
Studying of Output Power Combining for Cascaded Travelling-wave Photodiode Arrays
WEN Hua-feng, NIE Qiu-hua, LIU Tai-jun, XU Tie-feng, YING Xiang-yue, CLARK Kevin, and LI Ying-feng
In order to fabricate the high-power high-bandwidth photodector for radio-over-fiber communication, a optical-to-electrical conversion circuit of cascaded traveling-wave detector arrays for power combining was proposed. Traveling-wave photodiodes were cascaded and connected with inductors based on the structure of travIn order to fabricate the high-power high-bandwidth photodector for radio-over-fiber communication, a optical-to-electrical conversion circuit of cascaded traveling-wave detector arrays for power combining was proposed. Traveling-wave photodiodes were cascaded and connected with inductors based on the structure of traveling-wave detector arrays to obtain high-power high-bandwidth radio frequency signals. The optical-to-electrical conversion circuit was simulated with EDA tools. The simulation results show that the circuit combines the signals of the cascaded photodiodes effectively, which makes the bandwidth increase significantly. The results agree well with the theortetical analysis. In addition, circuits analysis indicates that the frequency bandwidth of the RF signal incereases effectively as the characteristic impendance increases..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 323001 (2015)
Sub-micron Chalcogenide Glass Ridge Waveguides with Anomalous Dispersion and Its Application to Optical Phase Conjugation
ZOU Lin-er, YAO Song-chao, CHEN Bao-xue, and MAMORU Iso
The finite element method was employed to analyze the effective refractive index and the dispersion characteristics for sub-micron As2S3 chalcogenide glass ridge waveguides with ridge height of 850 nm, ridge width of 800-2 000 nm, and etch depth of 200-600 nm. The results show that some certain structure ridge waveguidThe finite element method was employed to analyze the effective refractive index and the dispersion characteristics for sub-micron As2S3 chalcogenide glass ridge waveguides with ridge height of 850 nm, ridge width of 800-2 000 nm, and etch depth of 200-600 nm. The results show that some certain structure ridge waveguides have anomalous dispersion for the quasi-TM mode within optical communications band, and their zero dispersion wavelengths take place the blue shift with the increasing of etch depth in the same ridge width and ridge height. Moreover, there are two zero dispersion wavelengths in these waveguides with an appropriate structure, the As2S3 waveguide with ridge height of 850 nm, ridge width of 1 000 nm, and etch depth of 350 nm presents two the zero-dispersion wavelengths of 1 510 nm and 1 746 nm, and the dispersion value of -28.62 ps2·km-1 in the quasi-TM mode at 1 550 nm. On this basis, the As2S3 chalcogenide glass ridge waveguide with anomalous dispersion was used as an optical phase conjugation medium, and then applied in 220 km long distance fibre link with 3×40 Gb/s high bit-rate wavelength division multiplexing system by the experimental simulation. The results show this optical phase conjugator based on the chalcogenide glass ridge waveguide achieves availably the four-wave mixing effect and offers effectively the dispersion compensation for the whole system..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 323002 (2015)
A Tunable Terahertz Bandpass Filter with a Slit Aperture Flanked by Symmetrically Distributed Parallel Grooves on Both Sides
YUAN Ming-hui, and ZHAO Di
A low-cost and high efficient tunable terahertz (THz) bandpass filter on aluminum slab with a center slit flanked by symmetrically distributed parallel grooves on both sides was experimentally analyzed by the terahertz time domain spectroscopy (THz-TDS).Experimental results show that a high centre transmittance (>95A low-cost and high efficient tunable terahertz (THz) bandpass filter on aluminum slab with a center slit flanked by symmetrically distributed parallel grooves on both sides was experimentally analyzed by the terahertz time domain spectroscopy (THz-TDS).Experimental results show that a high centre transmittance (>95%) can be obtained at 0.33 THz because of the enhanced transmission effect induced by symmetrically coupled spoof surface plasmon polaritons (SSPPs).And the transmitted THz wave radiated from the slit aperture has a small divergence angle (approximately 5°).Moreover, the transmission peak splits into two peaks: the low-frequency peak shows redshift and the high-frequency peak shows blueshift when the incident tilting angle increases, and the transmission peak blue shifts when the incident pitching angle increases..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 323003 (2015)
Remote Sensing and Sensors
Super Resolution Optic Three-dimensional Imaging Based on Compressed Sensing
WANG Feng, LUO Jian-jun, TANG Xing-jia, LI Li-bo, and HU Bin-liang
A super resolution optic three-dimensional imaging based on compressed sensing was proposed for better optic imaging, in which imaging system was consisted of object glass, coding template, dispersion element, collimating lens, focus lens, detector in the front, hyperspectral data was reconstructed in the end by sparseA super resolution optic three-dimensional imaging based on compressed sensing was proposed for better optic imaging, in which imaging system was consisted of object glass, coding template, dispersion element, collimating lens, focus lens, detector in the front, hyperspectral data was reconstructed in the end by sparse reconstruction algorithm, so the most of data processing was transformed to the back-end from the imaging system. Meanwhile, Piece reconstruction, dislocation pretreatment and multi-frame reconstruction were used for improving accuracy of reconstruction, reducing memory of the back-processing, lowing computation complexity. By comparing the spectral curve, signal noise ratio, spectral error of the original and the reconstructed data cube, and doing classification and identification analysis, it was gained that the proposed compressed sensing could realize super resolution optic three-dimensional imaging, which have better property in imaging and data application, it can be used in big breath, high resolution, low power consumption and moving-target imaging observation..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 328001 (2015)
Super Resolution ISAR Imaging in Receiver Centered Region Area in Bistatic Radar
ZHANG Long, SU Tao, LIU Zheng, HE Xiao-hui, and DUAN Yong-qiang
For the time-variant property of bistatic angles in Receiver Centered Region Area in bistatic radar system, it′s difficult to obtain high resolution ISAR image of target in by using the conventional imaging methods.The signal model for bistatic ISAR was presented, then the time-variant property of the bistatic angles aFor the time-variant property of bistatic angles in Receiver Centered Region Area in bistatic radar system, it′s difficult to obtain high resolution ISAR image of target in by using the conventional imaging methods.The signal model for bistatic ISAR was presented, then the time-variant property of the bistatic angles and its influence on range envelope and azimuth was analyzed.A Radon-TCDS-Relax super-resolution imaging method was brought up for eliminate the effect from high-order azimuth terms of target motion model in receiver centered areas.The chirp rate and its changing rate corresponding to high-order phase terms in cross range was estimated by the proposed method.Scatterers extracting and imaging were achieved by Radon-TCDS-RELAX and TCD-RID respectively.Accuracy analysis and the experimental results with real data both demonstrate the effectiveness of the proposed method..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 328002 (2015)
Analysis of Underlying Surface Impact on Non-synchronous Alternative Spectral Calibration
XU Ai-jun, YUAN Juan, ZHANG Wen-juan, CHEN Zheng-chao, ZHANG Ya-qiong, and LI Hai-wei
In order to provide calibration image selection strategy for non-synchronous alternative spectral calibration, the oxygen absorption band near 760 nm was studied, spectral data of five underlying surface types of vegetation, withered vegetation, manmade objects, sand and snow were chosen to analysize. Based on simulateIn order to provide calibration image selection strategy for non-synchronous alternative spectral calibration, the oxygen absorption band near 760 nm was studied, spectral data of five underlying surface types of vegetation, withered vegetation, manmade objects, sand and snow were chosen to analysize. Based on simulated data, the analysis of calibration results and the accuracy was carried out, and spectral calibration errors of different underlying surface types was compared. Results showed that calibration errors based on the spectral angle matching method and the euclidean distance method are almost the same. When standard deviations of surface reflectance are less than 0.05 nm in 730 nm-800 nm, the spectral calibration precision is within ±0.5 nm. The olive green gloss paint and lush vegetation are not suitable to non-synchronous alternative spectral calibration..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 328003 (2015)
Humidity Sensor Based on Waist-enlarged Fiber Tapers Cascade Structure
ZHANG Yun-shan, QIAO Xue-guang, SHAO Min, FU Hai-wei, LI Hui-dong, and ZHAO Na
An in-fiber Mach-Zehnder interferometer humidity sensor based on waist-enlarged fiber tapers cascade structure was proposed and demonstrated.The sensor head is formed by a taper-single-mode-taper-single-mode-taper structure through arc fusion splicing.The change of the humidity and temperature will make the optical patAn in-fiber Mach-Zehnder interferometer humidity sensor based on waist-enlarged fiber tapers cascade structure was proposed and demonstrated.The sensor head is formed by a taper-single-mode-taper-single-mode-taper structure through arc fusion splicing.The change of the humidity and temperature will make the optical path difference changed of the sensor core mode and cladding modes, causing interference spectral change.Through monitoring the spectra variation can determine the ambient physical quantities.The experimental results show that the humidity sensitivity of the sensor is -0.065 dB/%RH with a linearity of 0.997 in the humidity range of 35-95%RH;the temperature sensitivity of the sensor is 69.4 pm/℃ with a linearity of 0.998 in the temperature range of 30-80 ℃.This sensor can avoid the cross-sensitivity to humidity and temperature, make it a good candidate for high accuracy humidity and temperature applications..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 44, Issue 3, 328004 (2015)
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