Journals >Acta Photonica Sinica
Contents
2016
Volume: 45 Issue 5
27 Article(s)
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Research Article
Performance Analysis of Atmospheric Boundary Layer Height Measurement in Nagqu Based on Ceilometer
LIAO Xi-wei, SONG Xiao-quan, WANG Dong-xiang, ZHANG Qian, DAI Guang-yao, and WU Song-hua
With the support of the Third Tibetan Plateau Experiment of Atmospheric Sciences, variations of the atmospheric boundary layer height of Nagqu area in summer(Jul-Aug 2014) were compared. Ceilometer derived atmospheric boundary layer height was estimated via gradient method of backscatter signal. The result shows that, With the support of the Third Tibetan Plateau Experiment of Atmospheric Sciences, variations of the atmospheric boundary layer height of Nagqu area in summer(Jul-Aug 2014) were compared. Ceilometer derived atmospheric boundary layer height was estimated via gradient method of backscatter signal. The result shows that, when the cloud top height is determined as atmospheric boundary layer height, the upper limit of convection boundary layer height could reach 3800 m. And, for nocturnal stable boundary layer, the lower limit is only 40 m. Radiosonde derived atmospheric boundary layer height was obtained using gradient method of potential temperature and relative humidity. By analyzing the valid dataset derived from the simultanious measurements of ceilometer and radiosonde within the 40 days, the correlation coefficient of atmospheric boundary height obtained by gradient method of backscatter signal and potential temperature, is calculated as 0.78, while the standard deviation is 738.84 m. In addition, it has been found that signal-to-noise ratio of ceilometer detection is insufficient under clear sky condition by analysis of 8 sets of abnormal data. In short, results indicate great diurnal variation of atmospheric boundary layer height by comparing daily measured data, which could be attributed to that the high altitude of Nagqu district causes stronger solar radiation compared to plain area, and hence intense diurnal variation of temperature and convection in summer..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 501001 (2016)
Aerosol Detection Method Based on Wide-Range Particle Spectrometer
LIU Xian-yun, Fang Jia-yi, LI Lei, and YUAN Chun-mei
In light of the interest that this class of atmospheric compounds currently attracts, the response of temperature on aerosol particle concentration was reviewed, through changing the temperature controlling method based on the Wide-range Particle Spectrometer(WPS). Firstly, the temperature of the sampling system of theIn light of the interest that this class of atmospheric compounds currently attracts, the response of temperature on aerosol particle concentration was reviewed, through changing the temperature controlling method based on the Wide-range Particle Spectrometer(WPS). Firstly, the temperature of the sampling system of the wide range particle spectrometer is changed by the switching of the tantalum tube heater and the non - heating temperature control system. With the improving sampling system, the ambient and room aerosol were detected. According to the distribution of atmospheric aerosol at different temperatures, the distribution of atmospheric aerosol is discussed and analyzed. Results show that compared with the room aerosol, the peak value of the number concentration for ambient aerosol is obviously larger than the room air, which means there are more large diameter particles in ambient aerosol. This research will lay the basis that Wide-range Particle Spectrometer is very suitable for the detection of aerosol, and provide a scientific basis for the detection of atmospheric aerosol pollution..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 501002 (2016)
Polarization Model of Quantized Gaussian Schell-model Fields in an Oceanic Turbulence
XIA Ming-chao, ZHANG Yi-xin, LI Ye, and WU Yu-qian
The effects of turbulence on the performance of the polarization degree of quantized Gaussian-Schell model beams propagating through oceanic optical communication channel were studied. The annihilation and creation operator of the linearly polarization quantized Gaussian Schell-beam were structured based on Huygens-freThe effects of turbulence on the performance of the polarization degree of quantized Gaussian-Schell model beams propagating through oceanic optical communication channel were studied. The annihilation and creation operator of the linearly polarization quantized Gaussian Schell-beam were structured based on Huygens-fresnel principle of quantized field in oceanic water. An expression for the polarization properties of Gaussian Schell-model quantization fields propagating through the oceanic channel is derived based on the spatial power spectrum of the refractive index of ocean water. The numerical experimental results show that under given parameters, as the ratio of temperature and salinity contributions to the refractive index spectrum varies from －4.5 to －0.5, the polarization degree decreases from 0.75 to 0.21；when the number of receiving photon increases from 20 to 50, the polarization degree also increases from 0.91 to 0.96; when the source′s transverse size varies from 0.02 m to 0.12 m, the polarization degree changes from 0.82 to 0.97; the effects of temperature-induced polarization decrease is surpassing the effects of salinity fluctuations；increasing the launch photon number and the radius of the aperture are an effective way to mitigate turbulent disturbance..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 501003 (2016)
Modeling Analysis and Calculation of a Brillouin Optical Time Domain Reflectometer System Using Multi Longitudinal Mode FP Laser
LI Yong-qian, CAO Cui-xin, LI Xiao-juan, and AN Qi
By using the theory of coherent detection, a Brillouin optical time domain reflectometer sensing system was proposed based on the external modulation of multi-longitudinal mode Fabry-Perot laser and the self-heterodyne detection of Rayleigh and Brillouin scattering. The principles of the stimulated Brillouin scatteringBy using the theory of coherent detection, a Brillouin optical time domain reflectometer sensing system was proposed based on the external modulation of multi-longitudinal mode Fabry-Perot laser and the self-heterodyne detection of Rayleigh and Brillouin scattering. The principles of the stimulated Brillouin scattering threshold improvement by the utilization of the multi-longitudinal mode Fabry-Perot laser, the self-heterodyne detection of Rayleigh and Brillouin scattering were analyzed, the expression of signal-to-noise ratio of the system was deduced, and the longitudinal mode number dependences of peak power and bandwidth of superposed Brillouin spectrum, and signal to noise ratio, temperature and strain measurement accuracy of the system were analyzed and calculated. The results show that with the increasing of the longitudinal mode number, the signal to noise ratio, temperature and strain measurement accuracy of the system at the end of 25 km long fiber are improved significantly for a multi-longitudinal mode Fabry-Perot laser with a mode interval of 0.141 nm, and the optimal value of temperature and strain measurement accuracy is 3.81 ℃ and 86.69 με respectively, when the longitudinal mode number takes the number of 19..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 506001 (2016)
Nonlinear Propagation Characteristic of the Short-Interval Pulse Trains and Chaotic Soliton Wavepacket Generation in Optical Fibers
DU Xian-tong, ZHONG Xian-qiong, CHENG Ke, and SHENG Jia-nan
The nonlinear propagation characteristic of the short-interval pulse trains in the anomalous dispersion regions of optical fibers was investigated numerically by adopting split-step Fourier algorithm for time intervals between two adjacent elementary pulses respectively being 1, 2, and 3, and number of elementary pulseThe nonlinear propagation characteristic of the short-interval pulse trains in the anomalous dispersion regions of optical fibers was investigated numerically by adopting split-step Fourier algorithm for time intervals between two adjacent elementary pulses respectively being 1, 2, and 3, and number of elementary pulses being 9, 17, and 25. The results indicate that, although the pulse number, pulse position, pulse intensities, and the time interval between two adjacent pulses, may vary with distance, and although the weak pulse pedestal may extend to very wide temporal range during propagation, the whole main wavepacket all along maintains localized with their temporal duration being nearly unchanged instead of broadening obviously and rapidly. What is more, the main pulse wavepacket never repeats its previous profile, which means that the wavepacket evolution exhibits chaotic behavior. Thus, in this sense, the nonlinear evolution of short-interval pulse trains can cause the chaotic soliton wavepacket generation. Both the elementary pulse time interval and pulse number of the pulse trains affect the chaotic soliton wavepacket in terms of its sub-pulse number and especially its temporal duration..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 506002 (2016)
Ultrasonic Detection of Metal Sheet Using Fiber Bragg Grating
ZHENG Yan, YU You-long, MEI Yu-jie, and LI Hui
A detection system of ultrasonic stress wave based on fiber Bragg grating was established, whose working principle was expressed. The linear relationship between the output voltage and plate strain based on the connection between the dynamic strain and center wavelength shift of fiber Bragg grating was derived. A pulseA detection system of ultrasonic stress wave based on fiber Bragg grating was established, whose working principle was expressed. The linear relationship between the output voltage and plate strain based on the connection between the dynamic strain and center wavelength shift of fiber Bragg grating was derived. A pulse of 28 kHz generated by ultrasonic signal generator drived the ultrasound vibrator, the signal was conveyed to a 5052 aluminum alloy plate through a organic glass wedge to generate stress waves which were detected by a fiber Bragg grating strain sensor. After that, a new wave packet appeared in the measured ultrasonic waves when there was a crack of 98 mm in the plate. The arriving time difference between the new wave packet before and after the damage can be used to determine the crack location. The position deviation of the crack is 2.7 mm. It is shown that instead of an ultrasound probe, the fiber Bragg grating can be used to detect the low-frequency ultrasound waves..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 506003 (2016)
Blind Separation Algorithm for Hyperspectral Image Based on the Denoising Reduction and the Bat Optimization
JIA Zhi-cheng, XUE Yun-yan, CHEN Lei, GUO Yan-jun, and XU Hao-da
In order to solve the problem that the blind source separation is difficult to be directly applied to the hyperspectral unmixing, the linear spectral mixture model was introduced in the presence of Abundance Non-negative Constraint (ANC) and Abundance Sum-to-one Constraint (ASC) as the objective function of the blind sIn order to solve the problem that the blind source separation is difficult to be directly applied to the hyperspectral unmixing, the linear spectral mixture model was introduced in the presence of Abundance Non-negative Constraint (ANC) and Abundance Sum-to-one Constraint (ASC) as the objective function of the blind source separation to change the traditional independence assumption. Then, the Bat Algorithm (BA) was introduced to optimize the objective function. This algorithm solves the problem that the traditional gradient optimization algorithm is easy to fall into the local extremum. A method was proposed for dimensionality reduction, which is based on Singular Value Decomposition Denoising-orthogonal Subspace Projection (SVDD-OSP). The experimental results on synthetic data and real remote sensing data indicate that the proposed algorithm has a high convergence rate and a high accuracy. In addition, it has the strong anti noise interference ability and can be applied to the data with a low purity..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 511001 (2016)
Non-diffraction Beam Improves the Resolution Ratio of Imaging System
CHEN Zi-yan, HU Wei-wang, WU Feng-tie, ZHU Qing-zhi, and HE Yan-lin
An incoherent source non-diffraction beam imaging system was designed under incoherent source by using the axicon. The formula of the resolution of the imaging system was derived based on the the diffraction integral theory and the point spread function of the system. The optical software was used to simulate the initiAn incoherent source non-diffraction beam imaging system was designed under incoherent source by using the axicon. The formula of the resolution of the imaging system was derived based on the the diffraction integral theory and the point spread function of the system. The optical software was used to simulate the initial structure model of the non-diffraction beam imaging system. With a blue light LED as the light source, combining with the optical components such as the striped object, lens and axicon, the experimental verification was conducted. According to the experimental results, the incoherent source non-diffraction Bessel beam imaging system can enhance the image resolution by applying the non-diffraction beam properties, which is consistent with theoretical derivation..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 511002 (2016)
Principle and Tolerance Analysis of a Rotating Parallel-mirror-pair Spectrometer
CAI Qi-sheng, XIANG-LI Bin, FANG Yu, and TAN Zheng
The tolerance of a rotating parallel-mirror-pair spectrometer (RPMPS) and some other considerations are analyzedusing the modulation depth and the phase error criterion.These include the vibration of the parallel-mirror-pair (PMP), the alignment error of the fixed end mirrors, the parallelism of the two rotating mirrorThe tolerance of a rotating parallel-mirror-pair spectrometer (RPMPS) and some other considerations are analyzedusing the modulation depth and the phase error criterion.These include the vibration of the parallel-mirror-pair (PMP), the alignment error of the fixed end mirrors, the parallelism of the two rotating mirrors, and the field of view. The theoretical results show that the vibration of the PMP is the most sensitive factor to RPMPS. However, as an ultra rapid continuous rotational system, the rotation inertia will reduce the effect of the vibration dramatically. The RPMPS is less sensitive to the parallelism of the two rotating mirrors. The tolerance for the alignment error of the fixed end mirrors and the field of view are similar to the traditional Michelson interferometer. Compared to the traditional linear motion form spectrometer, the RPMPS is an ultra rapid scanning Fourier-transform spectrometer with stability advantages.These analyses will also give a theoretic guidance for system design and manufacture of RPMPS..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 512001 (2016)
Research on System Calibration of Structured-Light Measurement Based on Neural Network
QI Zhao-shuai, WANG Zhao, HUANG Jun-hui, XUE Qi, and GAO Jian-min
A structured-light system calibration method based on a neural network was proposed. By using the method of projective transformation and error compensation, the mapped relation between the camera image plane and the projector image plane was obtained. Then, with the relation and the camera image-coordinates, the correA structured-light system calibration method based on a neural network was proposed. By using the method of projective transformation and error compensation, the mapped relation between the camera image plane and the projector image plane was obtained. Then, with the relation and the camera image-coordinates, the corresponding projector image coordinates were calculated. So, a three-layer neural network was constructed. For this network, the inputs are two image coordinates and outputs are 3D world coordinates. The training set consists of two image coordinates and 3D world coordinates of calibration points. Then, the neural network was trained by Back Propagation (BP) algorithm while the system model was fitting with it. When the process of the training was finished, the calibration was also accomplished. The results of the experiments prove that the method proposed in the paper reveals a higher degree of accuracy comparing with the conventional methods, and reduces the complexity of the model and simplifies the process of calibration. Besides, it can be applied in various conditions gererally..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 512002 (2016)
Study of Large Field of View Compound-eye Orientation Technology
GUO Shu-ji, SHI Li-fang, CAO A-xiu, WU Xiang-dong, and DENG Qi-ling
Aiming at the target detection in a large field of view, a localization method was presented based on the artificial compound-eye. By analyzing the relationship between the sub eye Field of View angle and the total Field of View angle, combining with the consideration about the sub eye arrangement of multi-vision positAiming at the target detection in a large field of view, a localization method was presented based on the artificial compound-eye. By analyzing the relationship between the sub eye Field of View angle and the total Field of View angle, combining with the consideration about the sub eye arrangement of multi-vision positioning, the designed method of artificial compound eye structure was studied which contains multiple sub eyes and can realize the detection in a large field of view. To analyze the three-dimensional space mapping law, the two dimensional images were cropped and mapped to 3D space, and the large field of view in 3D space was realized. To analyze the relationship between the sub image coordinates and the three-dimensional coordinates, the mathematical model of multi vision object location was established and the target location algorithm was compiled. A prototype was manufactured which contains of 19 sub eyes and can achieve 120 degree angle of large field of view, and the system parameters were obtained by Zhang Zheng-you calibration method. Then we carried out the 3D localization experiments. Experimental results show that the positioning error is 0.19% when we use the artificial compound eye imaging system to detect the target in 5.35 m..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 512003 (2016)
Multi-Camera Calibration Based on Vanishing Point Constraint
ZHANG Chao, YANG Hua-min, HAN Cheng, and YANG Fan
As for the one-dimensional multi-camera calibration algorithm of low precision, anti-manic and poor stability, a multi-camera calibration algorithm was proposed based on the mutual constraint among vanishing points. In order to avoid the impact of radial distortion caused by the imaging, the geometric characteristics oAs for the one-dimensional multi-camera calibration algorithm of low precision, anti-manic and poor stability, a multi-camera calibration algorithm was proposed based on the mutual constraint among vanishing points. In order to avoid the impact of radial distortion caused by the imaging, the geometric characteristics of position constrains in Euclidean space were used to calculate the distortion parameters. By combining the constraints of target feature points with projective invariance of camera to eliminate interference of miscellaneous points, then the consistency of angles in the space vanishing points, line which consisted of target feature points and the parallelism of the reverse-ray of the vanishing points were used to calculate the camera parameters. When one-dimensional targets move randomly, a critical problem is existed which is inability to distinguish the target feature points corresponding to the image points, this problem can be avoided by taking use of the inverse theory of mathematical analysis. By constructing the multi-camera system to calibrate the experiments, we can see that this method has a higher precision calibration, the calibration results have a certain degree of noise immunity and stability with the increasing of noise. The relative error value shows that this method can be applied in multiple camera systems..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 512004 (2016)
Fisheye Camera Calibration Algorithm Optimized by Centroid Method
SONG Tao, CHU Guang-yu, HOU Pei-guo, LI Hai-bin, and CHEN Chen
Due to the low calibration accuracy for fisheye lenses by using circular control points, this paper proposes a fisheye camera calibration algorithm optimized by centroid method. Firstly, initial values of intrinsic and extrinsic parameters of imaging model were obtained, and then initial value of distortion parameters Due to the low calibration accuracy for fisheye lenses by using circular control points, this paper proposes a fisheye camera calibration algorithm optimized by centroid method. Firstly, initial values of intrinsic and extrinsic parameters of imaging model were obtained, and then initial value of distortion parameters were solved by Two Step method. Secondly, centroid of ellipse detected from image and ellipse projected by imaging model were solved respectively. Then distance between those two centroid was minimized and cost function was established in order to optimizing the model′s parameters. Finally, parameters of imaging model were calibrated precisely. Experiment results with quantitive and qualitative comparison show that our method can improve the accuracy of calibration for fisheye lens..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 512005 (2016)
Influence of Temperature on “Smile” in High Power Diode Laser Bars
WANG Shu-na, ZHANG Pu, XIONG Ling-ling, NIE Zhi-qiang, WU Di-hai, and LIU Xing-sheng
By the numerical modeling and experimental test, the influence of temperature on “smile” was studied. By using the finite element method, the thermal stresses induced during bar bonding and operating process were simulated respectively. In simulations, it is assumed that the deformation of the laser bar is only caused By the numerical modeling and experimental test, the influence of temperature on “smile” was studied. By using the finite element method, the thermal stresses induced during bar bonding and operating process were simulated respectively. In simulations, it is assumed that the deformation of the laser bar is only caused by the thermal stress. The simulated results show that the thermal stress across the laser bar decreases with the increasing of heatsink temperature. As thus, the curve of the laser bar induced by packaging thermal stress will decrease with the increasing of the temperature. In this experiment, “smile” of five samples from the same wafer and batch was measured under different heatsink temperatures. Experimental results show that “smile” of the five samples increases or decreases as heatsink temperature increasing. The possible reason which is related with the combined action between the primitive bending shape of the bare bar and the mounting thermal stress. If the bare bar before packaging is flat or convex, “smile” of the diode laser bar will decrease as the heatsink temperature increasing. In addition, if the bare bar is concave and the laser bar is still concave after packaging, “smile” will increase with the increasing of heatsink temperature..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 514001 (2016)
Numerical Simulation of Femtosecond Laser Multi-Pulse Ablation of Ni-Ti Alloy
ZHANG Yan-fei, WANG Lei-lei, and GONG Jin-liang
In order to study the influence of the femtosecond multi-pulsed laser accumulation effect on the Ni-Ti alloy material, by considering the time interval to rewrite the laser source terms in the two-temperature equation, improving the two-temperature model, and using the finite-difference method, the distribution of femtIn order to study the influence of the femtosecond multi-pulsed laser accumulation effect on the Ni-Ti alloy material, by considering the time interval to rewrite the laser source terms in the two-temperature equation, improving the two-temperature model, and using the finite-difference method, the distribution of femtosecond three-pulse laser ablation of Ni-Ti alloy temperature field was simulated. The temperature evolution of electron and lattice with time and ablation depth was attained, and the internal mechanism of multi-pulse accumulation effect was also analyzed. Then the influence of different parameters on the temperature of electrons and lattices under the condition of three pulses was discussed. The results show that, under the ablation of the femtosecond three-pulses on Ni-Ti materials, electron has three increments of peak temperature, which is compared with the effect of single pulse, the three- pulses make the electron and lattice temperature increase significantly. The time interval is an important parameter for multi-pulse, which can directly affect the accumulation effect of multi- pulses. The pulse width mainly affects the peak temperature and the time to reach the peak temperature. The laser energy density mainly affects the temperature of electrons and lattices. The electron-lattice coupling coefficient also has an important influence on the coupling time of electron and lattice and the equilibrium temperature of electron and lattice..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 514002 (2016)
Optimum Directional Detonating Technology of Pulsed Laser Circumferential Detection
XU Xiao-bin, and ZHANG He
According to the requirements of the optimum directional detonating of conventional ammunition, the models of optimum detonating delay time and optimum detonating azimuth were established for single and double scan of the pulse laser circumferential detection system. Matlab is used to simulate the parameters of the modAccording to the requirements of the optimum directional detonating of conventional ammunition, the models of optimum detonating delay time and optimum detonating azimuth were established for single and double scan of the pulse laser circumferential detection system. Matlab is used to simulate the parameters of the model. The influence of detection azimuth, missile-target distance and target pitch angle on the optimum delay time and the detonating azimuth was analyzed. When the laser circumferential detection system scans a target once, the optimal initiation time increase withs the increasing of the missile-target distance, and then increases with the increasing of the azimuth. The change range of the optimal initiating delay is between 0 ms and 20 ms. When the pulse laser circumferential detection system scans target twice, the optimal initiation delay time is 0 ms in most of the time. In the non-zero region, the optimal initiation delay increases with the increasing of missile-target distance..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 514003 (2016)
Numerical Simulation and Experimental Study of Multi-band Trace TNT Detection by Imaging
LIU Hao, SHI Jia-ming, YUAN Zhong-cai, and LIU Yang
The simulation of CO2 laser illumination on explosives was implemented. The three-dimensional models are built for the study of radiation temperature variation of the target surface during process of laser illumination and cooling down in 8~14 μm and 3~5 μm waveband. The target with explosive residues are observed withThe simulation of CO2 laser illumination on explosives was implemented. The three-dimensional models are built for the study of radiation temperature variation of the target surface during process of laser illumination and cooling down in 8~14 μm and 3~5 μm waveband. The target with explosive residues are observed with the thermal imaging equipment(8~14 μm and 3~5 μm). The studies show that the radiation temperatures of TNT and substrates are determined by the emissivity and reflectivity in process of laser illumination in 8~14 waveband. The radiation temperatures of TNT and substrates are determined by the emissivity in 3~5 μm. In the illumination process, the radiation temperature of TNT areas is higher than surrounding areas in 8~14 μm waveband. In 3~5 μm, the radiation temperature of target surface has decreased instantly, and the radiation temperature of stained areas is lower than surrounding areas..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 514004 (2016)
Influence of the Silica Films Inserted into Silicon Substrate on the Light Trapping Performance of Silver Nanoparticles
BAI Yi-ming, YAN Ling-ling, WANG Yan-ning, SU Lin, LIU Hai, CHEN Nuo-fu, and YAO Jian-xi
Introducing silica dielectric film deposited by magnetron sputtering on silicon substrates, the dependence of the surface coverage ratio, morphology, formation mechanism and optical properties for silver nanoparticles on silica dielectric film was exploited. The results indicate that the surface coverage ratios of silvIntroducing silica dielectric film deposited by magnetron sputtering on silicon substrates, the dependence of the surface coverage ratio, morphology, formation mechanism and optical properties for silver nanoparticles on silica dielectric film was exploited. The results indicate that the surface coverage ratios of silver nanoparticles increase but the mean diameters for silver nanoparticles decrease obviously after introducing silica dielectric film. The reason of morphological evolution for silver nanoparticles was explained by an improved model for silver film rupture based on the formation mechanism of silver nanoparticles. A red shift of up to 86 nm of the dipole extinction peak of silver nanoparticles is realized by adjusting the thickness of the silica film but the peak intensity decrease greatly, as analyzed by an ultraviolet-visible spectrophotometer. Numerical simulations of the optimized structures demonstrate that the number of scattered photons by the silver nanoparticles is decreased by as much as 2×1018 after inserting a silica layer. Therefore, it is undesirable to deposit silica layer on silicon substrate before silver nanoparticle formation for the light trapping performance of silver nanoparticles..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 516001 (2016)
Reflection Characteristics of One-dimensional Polybasic Photonic Crystals by Using Heterostructure
DENG Li-er, and GONG Lei
The reflection characteristics of one-dimensional polybasic photonic crystals by using heterostructure were studied by transfer matrix method．The influence of the disorder of three element compound dielectric layers was mainly disscused. The results indicate that the heterostructure consists of two one-dimensional polyThe reflection characteristics of one-dimensional polybasic photonic crystals by using heterostructure were studied by transfer matrix method．The influence of the disorder of three element compound dielectric layers was mainly disscused. The results indicate that the heterostructure consists of two one-dimensional polybasic photonic crystals with suitable photonic bandgap can substantially enlarge omnidirectional reflection frequency range. When the incident angle is in the range of 0°～89°, the band of total refection can be achieved from 0.410w/w0to 0.785w/w0. Completed with the two element compound dielectric layers, three element photonic crystals can decrease the influence of the disorder produced in crystal preparation process. The results provide theoretical support for the preparation and application of wide-angle reflector invisible and infrared light band..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 516002 (2016)
Preparation and Optical Properties of SiO2@Fe3O4@C Colloidal Nanoparticles
WANG Chong-yang, QIAO Xuan-xuan, SUN Ai-hua, GUO Jian-jun, ZHU Yue-jin, and XU Gao-jie
Highly dispersed SiO2@Fe3O4@C core-shell nanoparticles with controllable particle sizes were prepared. Under electric field, the optical properties of SiO2@Fe3O4@C nanoparticle suspensions of different size, different concentrations, different the solvent was studied, and the results show that the reflection spectrum oHighly dispersed SiO2@Fe3O4@C core-shell nanoparticles with controllable particle sizes were prepared. Under electric field, the optical properties of SiO2@Fe3O4@C nanoparticle suspensions of different size, different concentrations, different the solvent was studied, and the results show that the reflection spectrum of 150 nm SiO2@Fe3O4@C nanoparticles at a concentration of 10%(mass fraction) obtain the widest tunable range from 735 nm to 540 nm. With increasing concentration of nanoparticle suspension, the overall reflectance spectra blue shift. The solvent dependence of the electric field-responsive photonic crystals by dispersing 150 nm particles into different solvents was investigated, and the results show that the greater refractive index, the greater the reflection wavelength. The response time of the suspensions is 150 ms, and the suspensions have recovery after electric field disappeared..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 516003 (2016)
Preparation of TiO2-AgNPs Surface Enhanced Raman Basal and Its Active Research
YAO Juan-juan, WU Shi-fa, JIN Shang-zhong, CHEN Hua-cai, TONG Jing, and DING Jian-hua
Three different lasers with the wavelengths of 532, 632.8 and 785 nm, were used and have been given a preferable TiO2-AgNPs basement suited to each wavelength. On this condition,Raman spectra experiment of R6G and serum were conducted. When the lifting speed is up to 200 mm/min, photocatalytic activity of TiO2 thin filThree different lasers with the wavelengths of 532, 632.8 and 785 nm, were used and have been given a preferable TiO2-AgNPs basement suited to each wavelength. On this condition,Raman spectra experiment of R6G and serum were conducted. When the lifting speed is up to 200 mm/min, photocatalytic activity of TiO2 thin films is no longer increased. In the range of 440~600 degrees, Titania crystal is still an anatase structure. Film thickness, temperature and ultraviolet irradiation time have an influence on the growth of silver particles together, 200 mm/min pulling speed, 520 ℃ calcination temperature and UV irradiation 80 min's condition can give TiO2-AgNPs basement a better Raman enhancement factor.It is found that the excitation laser with different wavelength has an obvious effect on spectrum.For 532 nm ,the enhancement factor of large wave number'spectral peak is significantly higher than that of small wave number,the conclusion is just opposite when laser of 785nm is used.SERSp drived by 632.8nm of the laser wavelength is different form the other two consequences and show uniform enhancement factor between large and small wave number.Paper analyzes fluorescence excitation's contribution to the Raman enhancement may be the main influence factors which lead to the SERp's significant difference ..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 516004 (2016)
Spectral Properties of Ho3+/Tm3+ Co-doped α-NaYF4 Single Crystals
FENG Zhi-gang, XIA Hai-ping, WANG Cheng, JIANG Dong-sheng, ZHANG Jian, HE Shi-nan, TANG Qing-yang, SHENG Qi-guo, ZHANG Yue-pin, GU Xue-mei, JIANG Hao-chuan, and CHEN Bao-jiu
Cubic NaYF4 single crystals co-doped with ~1.90 mol% Ho3+ and various Tm3+ concentrations (0.99mol%, 1.58 mol%, 2.37 mol%, 3.16 mol%, 3.99 mol%, 7.19 mol%) were grown by using the Bridgman method. The energy transfer from Tm3+ to Ho3+, concentration quenching of Tm3+ and the optimum fluorescence emission around 2.04 μmCubic NaYF4 single crystals co-doped with ~1.90 mol% Ho3+ and various Tm3+ concentrations (0.99mol%, 1.58 mol%, 2.37 mol%, 3.16 mol%, 3.99 mol%, 7.19 mol%) were grown by using the Bridgman method. The energy transfer from Tm3+ to Ho3+, concentration quenching of Tm3+ and the optimum fluorescence emission around 2.04 μm of Ho3+ ion were investigated based on the measured absorption spectra, emission spectra, emission cross section and decay curves under excitation of 800 nm LD. The emission intensity at 2.04 μm increased with the increasing of Tm3+ concentration from 0.99 mol% to 1.59 mol%, and decreased with the increasing of Tm3+ concentration from 1.59 mol% to 7.19 mol% when the concentration of Ho3+ was held constantly at ~1.90 mol%. Moreover, the maximum emission cross section reached to 2.17×10－20 cm2 and the maximum fluorescence lifetime was 21.72 ms for Ho3+(1.90 mol%)/Tm3+(1.59 mol%) co-doped one. At the same time, the energy transfer coefficients of this sample were calculated based on the absorption cross-section of Ho3+ and the emission cross-section of Tm3+, which is CTm-Ho=21.14×10－40 cm6/s and CHo-Tm=2.05×10－40 cm6/s respectively..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 516005 (2016)
Optimal Design of High-speed SOH Electro-optic Modulator Based on SOI
LI Kai-li, AN Jun-ming, ZHANG Jia-shun, WANG Yue, WANG Liang-liang, WU Yuan-da, LI Jian-guang, YIN Xiao-jie, and WANG Hong-jie
A push-pull high-speed silicon-organic hybird Mach-Zahnder interference electro-optic modulator was designed based on silicon on insulator. By using beam propagation method, the structure of 3 dB beam splitter/beam combiner on the silicon on insulator (top silicon thickness is 220 nm) has been simulated optimally whoseA push-pull high-speed silicon-organic hybird Mach-Zahnder interference electro-optic modulator was designed based on silicon on insulator. By using beam propagation method, the structure of 3 dB beam splitter/beam combiner on the silicon on insulator (top silicon thickness is 220 nm) has been simulated optimally whose insertion loss is 0.106 dB. Mode converter was designed between stripe waveguide and slot waveguide to realize an efficient transformation of optical transmission mode, and the coupling efficiency is as high as 98.8% . Also, the influence of doping concentration of slot waveguide slab area on optical loss of slot waveguide was analyzed by using finite-difference time domain method when the doping concentration is 7×1017/cm3, the optical loss is nearly zero. The total loss of the modulator is 0.493 dB. Considering the effect of slot waveguide equivalent capacitance and slab area equivalent resistance on the bandwidths, the waveguide structure was simulated by film mode matching solver and the optical field confinement factor can be optimized to 0.199. The ultrafast pockels effect was exploited by using the silicon-organic hybird platform, which combines highly nonlinear organic materials with slot waveguides, and realizes a voltage-length of 1.544 V·mm and a bandwidth of 137 GHz..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 523001 (2016)
Wavelength-routed Four-port Optical Router Based on Parallel-coupled Microring Resonators
LI Cui-ting, ZHENG Wen-xue, ZHENG Chuan-tao, ZHANG Da-ming, WANG Yi-ding, and MA Chun-sheng
By adopting four parallel-coupling one microring resonator as basic routing elements, a kind of four-port optical router is proposed, which can passively route three channel wavelengths. The structural parameters of the routing element were optimized for single-mode transmission, low optical loss and phase-match betweeBy adopting four parallel-coupling one microring resonator as basic routing elements, a kind of four-port optical router is proposed, which can passively route three channel wavelengths. The structural parameters of the routing element were optimized for single-mode transmission, low optical loss and phase-match between microring waveguide and channel waveguide. The device architecture as well as design scheme of the router was presented, and routing characteristic including spectrum characteristic, insertion loss and crosstalk were calculated. Under the selected three channel wavelengths of 1 550, 1 551.6 and 1 553.2 nm, the insertion losses along all routing paths are within 0.02~0.6 dB, and the crosstalk ranges from －23.41 to －37.71 dB. Compared with the previously reported four-port optical router using cross-coupling two microring resonator and the same waveguide parameters, the proposed router reveals slightly higher crosstalk and inferior spectral selectivity, but it does show smaller insertion loss (decreasing from 1.62 dB to 0.02 dB) and uses less rings (decreasing from 8 to 4)..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 523002 (2016)
The Influence of Modulating Loss on the Nonlinear Property of the MZI-based Optical Silicon Modulator
GUI Lin, ZUO Jian-cun, SHAO Yu-feng, SUN Qiu-dong, WANG Sheng-li, and ZHOU Zhi-bin
Aiming at the nonlinear electro-optical response in the Mach-Zehnder Interferometer (MZI)-based silicon modulator, the model with the nonlinear modulating loss in PN junction and the nonlinear refractive index changing was utilized, and the influence of modulating loss on the silicon modulator was investigated for two Aiming at the nonlinear electro-optical response in the Mach-Zehnder Interferometer (MZI)-based silicon modulator, the model with the nonlinear modulating loss in PN junction and the nonlinear refractive index changing was utilized, and the influence of modulating loss on the silicon modulator was investigated for two cases: symmetric arm or asymmetric arm in the MZI-based modulator. By taking account of the modulating loss in the model, the results can be obtained that in the condition of large signal, the third order harmonic component is enhanced and the fourth order harmonic component is reduced when the bias phase of the optical modulator is 0, and the second order and fourth order harmonic component are all enhanced when the bias phase of the optical modulator is π/2. While in the condition of small signal, the high order harmonic components, such as the third order and fourth order harmonic components, are not obvious, and the crosstalk of fundamental frequency is enhanced by the modulating loss when the bias phase of the optical modulator is 0 and two arms in the modulator are asymmetric, the second order harmonic component is enhanced by the modulating loss when the bias phase of the optical modulator is π/2..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 523003 (2016)
Recognition of Transgenic Soybeans Based on Terahertz Spectroscopy and PCA-BPN Network
NIE Jun-yang, ZHANG Wen-tao, XIONG Xian-ming, CHEN Tao, ZHAN Ping-ping, and TU Shan
An approach for recognition of transgenic soybeans was proposed based on spectral analysis in the terahertz (THz) range combing with Principle Component Analysis (PCA) and Back Propagation Neural (BPN) network. Eight principal component factors, whose accumulated variance reached 97.582%, were extracted from the originAn approach for recognition of transgenic soybeans was proposed based on spectral analysis in the terahertz (THz) range combing with Principle Component Analysis (PCA) and Back Propagation Neural (BPN) network. Eight principal component factors, whose accumulated variance reached 97.582%, were extracted from the original spectra data and then fed as inputs into the BPN network model. The utilization of the dimension-reduced data in training the network model can recognize the validation set accurately. The nondestructive testing of transgenic soybeans could be achieved by using THz spectroscopy, which could be widely applied in agricultural security areas..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 530001 (2016)
Detection on Particulate PollutantinTransformer oil Based on the Mid-Infrared Spectrum
CHEN Bin, HAN Chao, and LIU Ge
The different particle pollution degree in transformer oil samples were made up, the infrared spectrum data of the oil samples were acquired by using the infrared spectrum scanning. Using the successive projections algorithm, the effective wavelength variables of the oil samples were extracted. Based on the extracted wThe different particle pollution degree in transformer oil samples were made up, the infrared spectrum data of the oil samples were acquired by using the infrared spectrum scanning. Using the successive projections algorithm, the effective wavelength variables of the oil samples were extracted. Based on the extracted wavelength variables, two models of both the effective wavelength of the infrared spectrum and the particle contamination pollution degree were established by using partial least squares and support vector machine method. The effective wavelength of successive projections algorithm extracted from the infrared spectrum of transformer oil samples has the characteristics of the wavelength of specific particle contamination, and the prediction effects of the models are better than partial least squares model and support vector machine model using the full infrared spectrum data of the oil samples. Besides, the determination coefficient of the prediction set of oil samples are 0.892 9, 0.934 3 respectively with the two models, and the root mean square error are 6.372×10－3、3.07×10－3 respectively, thereby the satisfactory prediction results has achieved, these provide a reference for the detection of the particle contamination in transformer oil..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 45, Issue 5, 530002 (2016)
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