Journals >Acta Photonica Sinica
Contents
2013
Volume: 42 Issue 12
27 Article(s)
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Research Article
Modulation Instability in Metamaterials with Thirdorder Nonlinear Dispersion
ZHONG Xianqiong, CHENG Ke, and XIANG Anping
On the basis of the extended nonlinear propagation equation without normalization in metamaterials with the firstorder to thirdorder nonlinear dispersion effects, the dispersion relation and gain spectra of modulation instability were deduced by adopting the linear stability analysis and the Drude electromagnetic modOn the basis of the extended nonlinear propagation equation without normalization in metamaterials with the firstorder to thirdorder nonlinear dispersion effects, the dispersion relation and gain spectra of modulation instability were deduced by adopting the linear stability analysis and the Drude electromagnetic model. Variations of the equation coefficients and gain spectra with the normalized angular frequencies were calculated and discussed in real units in both the positive and negative refractiveindex regions in cases of selffocusing and selfdefocusing. The results show that, the thirdorder nonlinear dispersion coefficients are all along positive in both the positive and negative refractiveindex regions. In the negative refractiveindex region, with increase of normalized angular frequencies, the spectral widths of the gain spectra increase before become zero and the peak gains increase before decrease and then become zero in the selffocusing case. While in the case of selfdefocusing, modulation instability can only occur near the forbidden band and both the spectral widths and peak gains decrease monotonically. In the positive refractiveindex region, modulation instability can only occur in the selffocusing case. And the spectral widths increase monotonically and the peak gains decrease before increase with the normalized angular frequencies. Generally, the thirdorder nonlinear dispersion is detrimental to modulation instability generation..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1387 (2013)
Effect of Carbon Chamber Spatial Confinement on Metallic Laser Plasma Radiation
CHEN Jinzhong, MA Ruiling, WANG Jing, LI Xu, and SU Hongxin
In order to improve the quality of laserinduced breakdown spectroscopy and derive the optimal experiment condition, the change of the radiation intensity of laserinduced stainless steel plasma with and without a small carbon chamber is analyzed, which is excited by a high energy rubidium glass pulsed laser. The mechaIn order to improve the quality of laserinduced breakdown spectroscopy and derive the optimal experiment condition, the change of the radiation intensity of laserinduced stainless steel plasma with and without a small carbon chamber is analyzed, which is excited by a high energy rubidium glass pulsed laser. The mechanism of the laser induced plasma radiation intensity is discussed by measuring the electron temperature and electron density. The results show that when laser plasma is confined by a small carbon chamber with the height 9.0 mm and the internal diameter 4.0 mm, the spectral line intensities and signaltonoise ratio of the sample elements increase substantially. So the spectral quality can improve effectively by using the method of spatial confinement..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1392 (2013)
The Preparation of “Green” Novel Liquid Laser Medium and the Research on its Optimal Concentration and Operation Temperature
ZHANG Qiuhui, WANG Kefu, FENG Guoying, LI Mi, and SONG Yingsong
Double novel neodymium complex liquid laser medium were prepared based on Neodymium Oxide and 1, 10Phenanthroline. This laser medium was nontoxic, low cost, and well thermo stability. When cross relaxation was considered, the rate equations of every level particle were obtained while Nd3+ “green” novel liquid laser mDouble novel neodymium complex liquid laser medium were prepared based on Neodymium Oxide and 1, 10Phenanthroline. This laser medium was nontoxic, low cost, and well thermo stability. When cross relaxation was considered, the rate equations of every level particle were obtained while Nd3+ “green” novel liquid laser medium was excited. The relation between Nd3+ concentration and 4F3/2 luminescence strength was researched using rate equations, while absorption spectrum and luminescence spectrum were measured. The results show that the luminescence strength increases with concentration firstly and then decreases with concentration. The relation between operation time and luminescence strength are also researched..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1397 (2013)
Control of Selfbending Airy Beams
SHI Yaoyao, WU Tong, LIU Youwen, LI Yan, and ZHOU Rong
Freespace selfbending of nondiffracting Airy beams was theoretically investigated with Schrodinger's equation, the factors influencing selfbending were analyzed, which were linked to actual physical quantities, and the method of acceleration control of Airy beams with gradientindex material was given. The selfFreespace selfbending of nondiffracting Airy beams was theoretically investigated with Schrodinger's equation, the factors influencing selfbending were analyzed, which were linked to actual physical quantities, and the method of acceleration control of Airy beams with gradientindex material was given. The selfbending property appearing during propagation of one and twodimensional Airy beams was numerical simulated. Moreover, the numerical simulation results that the deflection of Airy beams can be compensated and reversed with proper control. The relationship between the propagation length of compensated finite Airy beam in a gradientindex material and the decay factor was discussed. The results show that the compensated finite Airy beam can keep nondiffracting propagation when intensity of the central lobe decays from maximum to eighteen percent of the maximal value. The relationship between the propagation length of compensated finite Airy beam in a gradientindex material and the central lobe width as well as the wavelength was also studied, respectively. In practical application, three appropriate parameter values and a right gradient refractive index material can be selected through the dependent relationship between the decay factor, the central lobe width as well as wavelength and the propagation length of compensated finite Airy beam at the instance of the propagation length of compensated finite Airy beam, and optimal control of Airy beam can be realized..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1401 (2013)
Gain Spectrum Flatness in Raman Fiber Amplifier
GONG Jiamin, ZUO Xu, YUAN Xinyi, XU Junhua, and FANG Jian
Gainflatness is a crucial parameter in wavelength division multiplexing system design. In this paper, the gain flattened theory by using multistage cascaded fiber was presented. The effective distance and Raman gain coefficient constraints were calculated. When spectrum was fitted by linear lines, the gainflattened Gainflatness is a crucial parameter in wavelength division multiplexing system design. In this paper, the gain flattened theory by using multistage cascaded fiber was presented. The effective distance and Raman gain coefficient constraints were calculated. When spectrum was fitted by linear lines, the gainflattened condition was simplified. The optimal gain value was obtained by cascading two stage fibers. The pure silica fiber and phosphorusdoped fiber were cascaded as the typical example. The results show that with the increasing length of the first stage fiber, the signal gain was firstly increased and then reduced; when the first fiber length was 7.15 km, 5.78 dB average maximum gain and 0.45 dB gain flatness were provided by Matlab. Pump power and signal gain was positively correlated. Three stage fibers were cascaded with different materials as the last example. 7.74 dB average gain and 0.57 dB flatness were verified by Matlab which proves the accuracy of the theory. This scheme provides a novel way to design gain flattened Raman fiber amplifier..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1408 (2013)
Limit Communication Rate of Visible Light Communication Datalink Based on Discrete Multitone Modulation
LI Yanting, LI Zhubo, ZHANG Hongwei, SHI Xingchen, and ZHENG Chuantao
In order to theoretically reveal the effects of signaltonoise ratio and the required bit error rate level on limit communication rate of a discrete multitone datalink, in this paper, the electrooptical transfer function of the transmitter, the opticalelectro transfer function of the receiver and the total transfeIn order to theoretically reveal the effects of signaltonoise ratio and the required bit error rate level on limit communication rate of a discrete multitone datalink, in this paper, the electrooptical transfer function of the transmitter, the opticalelectro transfer function of the receiver and the total transfer function of generalized visible light communication channel were analyzed. Mathematical modeling of discrete multitonevisible light communication system was finally established by sufficiently considering the time and frequencydomain responses of visible light communication channel. Fomulative relations of limit communication rate versus signaltonoise ratio and bit error rate level were derived. Analytical results show that, under definite signaltonoise ratio, the limit communication rate reveals doubleexponential increasing relation with bit error rate level; under definite bit error rate level, the limit communication rate reveals Boltzmann variation trend versus signaltonoise ratio. With the universal white light emitting diode and PIN detector, when the signaltonoise is 25 dB, the limit communication rate is within the range of 200~228 Mbps for requiring a bit error rate of <10－3, which shows good agreement with the reported experimental results (202~231 Mbps).The novel thereotical analysis method and mathematical modelling proposed in this paper can also be adopted to evaluate the limit communication rate of any discrete multitonevisible light communication system, and therefore they are efficient in system parameter optimization and component selection during the design of such kind of systems..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1414 (2013)
Optical 3D Digitizer for Photorealistic Imaging of Movable Cultural Heritage
LI Ameng, PENG Xiang, YIN Yongkai, and LIU Xiaoli
Computeraided optical digitization technique appears to be a powerful tool for the generation, storage, and retrieval of threedimensional digital information of cultural heritage, and therefore leading to a new generation of technology for digital preservation. In this paper, an efficient approach was presented for gComputeraided optical digitization technique appears to be a powerful tool for the generation, storage, and retrieval of threedimensional digital information of cultural heritage, and therefore leading to a new generation of technology for digital preservation. In this paper, an efficient approach was presented for generating photorealistic threedimensional image and model of movable cultural heritage. A dedicated color optical digitizer was also presented based on a strategy of modified fringe projection profilometry. The approach provided an efficient way to digitize and reconstruct photorealistic threedimensional images and digital models of movable cultural heritage. Experiment results using bronze wares with thinwall shape structures and complicated topologies as well as color attributes were given to demonstrate the feasibility of proposed method for digital preservation..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1421 (2013)
Total Variation Based Bandlimited Sheralets Transform for Image Denoising
LU Yaning, GUO Lei, and LI Huihui
Noise reduction is an important image preprocessing for improving the quality of image. Shearlet transform, as a method of multiscale geometric analysis, is more suitable for image processing because of better approximation precision and sparsity description. A novel approach based on the bandlimited shearlet transfoNoise reduction is an important image preprocessing for improving the quality of image. Shearlet transform, as a method of multiscale geometric analysis, is more suitable for image processing because of better approximation precision and sparsity description. A novel approach based on the bandlimited shearlet transform and total variation for image denoising was proposed. Unlike traditional hard threshold method, different thresholdings were used at each scale to obtain good estimate. The reconstruction image was used as initial image of total variation minimum method. Numerical examples demonstrated that the approach is highly effective at denoising complex images. Compared with other methods in multiscale geometric analysis domain, such as nonsubsampled contourlet transform, curvelet transform and hardthreshod method of shearlet transform, the denoised image in this paper removed the noise while retaining as much as possible the important signal features and details such as edges and texture information..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1430 (2013)
Multi angle Face Recognition Algorithm Based on MultiRKHS
LIN Shuo, GONG Zhiheng, HAN Zhonghua, and SHI Haibo
The traditional spectrum algorithms are limited in face recognition problem. For its characteristics of problem, a novel method based on multireproducing Kernel Hilbert space was proposed. Firstly, the images were processed by the landmark method, and the angle of training images could be obtained. Secondly, the face The traditional spectrum algorithms are limited in face recognition problem. For its characteristics of problem, a novel method based on multireproducing Kernel Hilbert space was proposed. Firstly, the images were processed by the landmark method, and the angle of training images could be obtained. Secondly, the face data was iterated by the Kernel, then face data expressed linearly in the reproducing Kernel Hilbert space. Thereafter, for many types of face data, the multireproducing Kernel Hilbert space were established. Finally, the reproducing Kernel Hilbert space belonging of human face image was judged by the comparison of training images, and the multiangle face recognition achieved. The two classes of data sets were selected as the experimental data, which consisted of FERET and CMUPIE. A large number of experiments were carried out. The results show that the proposed method has great effect to recognise multiangle face. The average recognition rate and efficiency are 5% and 20% higher than the traditional algorithms, respectively..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1436 (2013)
Stereo Visual Localization Based on Sequence Orthogonal Iterative Algorithm
XU Yunxi, QI Zhaoyi, and JIANG Yunliang
For the intelligent vehicle autonomous visual navigation need to get realtime, accurate, robust their own location information, a robust, efficient and accurate stereo visual localization algorithm is proposed. A new direct P3P pose estimation with RANSAC was proposed to obtain matching inliers and initial motion paraFor the intelligent vehicle autonomous visual navigation need to get realtime, accurate, robust their own location information, a robust, efficient and accurate stereo visual localization algorithm is proposed. A new direct P3P pose estimation with RANSAC was proposed to obtain matching inliers and initial motion parameters and greatly improve accuracy. Then a new motion parameters optimization method was proposed based on sequence orthogonal iterative algorithm for general camera models. Recent N frames motion and structure parameters of stereo camera were rapidly optimized online. Compared with bundle adjustment, the speed and robust of the proposed method greatly enhanced, and the proposed method could attain global convergence. The outdoor real experiments show this method has high accuracy, good robustness and high computing speed in localization that can meet the high performance requirement of navigation localization..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1442 (2013)
3D Face Recognition by Kernel Collaborative Representation Based on Gabor Feature
ZHAN Shu, ZHANG Qixiang, JIANG Jianguo, and Shigeru ANDO
To overcome the problem of illumination, facial expression and pose variants in 3D face recognition, the algorithm based on the Gabor features combined with kernel collaborative representation is proposed. Collaborative representation classification algorithm uses similar faces to describe testing faces collaborativelyTo overcome the problem of illumination, facial expression and pose variants in 3D face recognition, the algorithm based on the Gabor features combined with kernel collaborative representation is proposed. Collaborative representation classification algorithm uses similar faces to describe testing faces collaboratively. Via solving sparse coefficient by l2 norm, collaborative representation classification algorithm can classify the testing face correctly according to reconstruction error. This method extracts 40 Gabor features with different scales and orientations of depth maps by the Gabor filter firstly. Secondly, these features are mapped to a highdimensional space by selecting an appropriate kernel function. Finally, nonlinear dimensionality reduction and feature selection fulfill the recognition task in highdimensional space combining with collaborative representation classification. Extensive experiments on Kinect Face Dataset and Texas 3D face database demonstrate that the proposed algorithm is more effective than recently algorithms even when the number of training samples is small..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1448 (2013)
Circularviewing Hologram with Large Side Viewing Angle Generated by Combining Computer with Optical Holography
WU Dongyuan, WANG Hui, XIE Yutao, and YANG Xin
The circularviewing hologram can show 360° reconstruction of a object, so it has a great application value. For the purpose of increasing the viewingangle of the image and reconstructing it by white light, a new two steps method, Which combined computer with optical holography for making the circularviewing holThe circularviewing hologram can show 360° reconstruction of a object, so it has a great application value. For the purpose of increasing the viewingangle of the image and reconstructing it by white light, a new two steps method, Which combined computer with optical holography for making the circularviewing hologram, was proposed considering of the computer generated hologram. First, the algorithm of computer generated circularviewing plane hologram was studied, the propagation principle of object wave was derived, and the distribution pattern of the object wave on the recording plane was obtained meanwhile. Next, the influence of the angle between reference light and object light on spatial frequency of the hologram was discussed, the spatial frequency could be decreased by using a point reference light source, so it could increase the viewingangle. However, the image could only be viewed by laser. To solve this problem and to reconstruct the hologram by white light, optical setup for imageplane hologram was designed as the second step. Then, the relationship between spatial frequency of the hologram and the size of object, and the relationship between spatial frequency of the hologram and the viewing angle were deduced, and the curves of the relationships were also calculated. Finally, a 3D modeling gray object was used and the circularviewing hologram with large side viewing angle which could be reconstructed by white light was made. Therefore, the calculation method and optical design were verified. For circularviewing plane hologram, the technique can record realexisting objects and virtual objects and achieve the image by white light, and it can increase the viewingangle of the reconstruction at the same time..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1454 (2013)
Mode Properties of Hybrid Plasmonic Waveguide Based on Semiconductor Nanowire and Metal Ridge
ZHOU Pei, LU Qijing, WU Genzhu, and CHEN Daru
A hybrid plasmonic waveguide that consists of a semiconductor nanowire and semicirculartop metal nanoridge was proposed. Finite element method was used to numerically evaluate hybrid mode′s deep subwavelength field confinement and propagation loss etc. Simulation results reveal that mode area of 0.001 81(λ2/4) and proA hybrid plasmonic waveguide that consists of a semiconductor nanowire and semicirculartop metal nanoridge was proposed. Finite element method was used to numerically evaluate hybrid mode′s deep subwavelength field confinement and propagation loss etc. Simulation results reveal that mode area of 0.001 81(λ2/4) and propagation distance of 20 μm are obtained at the wavelength of 1.55 μm; the proposed waveguide has advantages of smaller mode area and longer propagation distance over other similar structures that has potential in fabrication of integrated photonic components and circuits..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1460 (2013)
Electromanetic Field Analysis of Slotwaveguide with High Refractive Index Difference
LI Tang, WANG Dongxu, QIAN Ruyi, CHENG Siqi, GU Ruirui, and LE Zichun
The slotwaveguide is widely used in the integrated optical waveguide devices and systems. Therefore it is very important to develop a practical theoretical method and model for guiding the design of such devices and systems. By means of analyzing the physical mechanism of the slotwaveguide and the modes transmitted iThe slotwaveguide is widely used in the integrated optical waveguide devices and systems. Therefore it is very important to develop a practical theoretical method and model for guiding the design of such devices and systems. By means of analyzing the physical mechanism of the slotwaveguide and the modes transmitted in it, a novel theoretical model was built to describe the electric field distribution in the slotwaveguide. The novel theoretical model was developed based on the conditions of regarding the nanowaveguides and the slot region as a whole system and of introducing both the guided wave and the radiating wave in solving the Helmholtz equation. In order to verify the proposed theoretical model, the theoretical results were compared with RSoft simulation results, a practical optimum design reported by other researchers, and a theoretical method developed by other researchers. The comparison results show that the proposed theoretical model has higher accuracy in describing the slotwaveguides. Finally, the significant condition of the proposed theoretical model was analyzed and determined. Take a typical SOI slotwaveguide with the nanowaveguide size of 180 nm×300 nm as an example, the critical slot width worked out at 96.2 nm..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1464 (2013)
Analysis and Optimum Design of Silicononinsulator Microring Resonator Electrooptic Modulator
WEI Liping, WANG Yonghua, ZANG Junbin, CUI Danfeng, LI Yanna, LIU Yaoying, and XUE Chenyang
Aiming at application requirements of highfrequency electrooptic modulators, a PIN type electrooptic modulator based on SOI resonator has been proposed. Describing the resonance characteristic of microring resonator via the Scattering Matrix Method, combining the variation of effective refractive index of siliconAiming at application requirements of highfrequency electrooptic modulators, a PIN type electrooptic modulator based on SOI resonator has been proposed. Describing the resonance characteristic of microring resonator via the Scattering Matrix Method, combining the variation of effective refractive index of silicon resulted from carrier concentration changing, the plasma dispersion effect, analyzing the theoretical model of the microring resonator electrooptic modulator systematically. Based on the simulation and analysis of the crosssection optical field distribution of rib waveguide by Rsoft simulation software, a design of rib waveguide microring resonator with better performance of optical field confinement has been obtained. Furthermore, the performance of the PIN type diode for different doping concentrations has been simulated by Sentaurus TCAD simulation software. Finally, a blue shift of 58.74GHz is achieved from the theoretical model. It is demonstrated that the optimum design of the electrooptic modulator is reasonable and meaningful in further study of electrooptic modulator..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1473 (2013)
A Variable Optical Attenuator Based on Liquid Optical Wedge
CHEN Tao, LIANG Zhongcheng, and XU Rongqing
A novel variable optical attenuator device of based of variablefocus liquid lens was proposed and fabricated, of which basic structure included a cylindrical precisiontube as the lens chamber and its side wall sandwiched between two collimators. Liquid lens approximated as optical wedge to form structure of “input colA novel variable optical attenuator device of based of variablefocus liquid lens was proposed and fabricated, of which basic structure included a cylindrical precisiontube as the lens chamber and its side wall sandwiched between two collimators. Liquid lens approximated as optical wedge to form structure of “input collimator＋adjustable lens prism＋output collimator”, the optical axis of the collimator run through the edge of the variable lens. The light emitted by the input fiber collimator deviated from the output fiber collimator best receiver position, through liquid lens electrowetting on dielectric analoging prism, to realize the fiber collimators coupling lightintensity and control optical attenuation. The experimental results show that the range of attenuation values of variable optical attenuato rise up to 2~53 dB, and can be used for demonstration of optical communication experiment, experimental teaching or other occasions..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1478 (2013)
Thermally Expanded Core Fiber Based MZ Filter and Its Application in Widely Tunable Erbiumdoped Fiber Laser
ZHOU Yingwu, and LUO Zhizao
Thermally expanded core fibers were made by heating a singlemode fiber locally with hydrogenoxygen flame. An all fiber MZ filter was fabricated using the thermally expanded core fiber, and it was inserted into a Sagnac filter to make a new structure of tunable fiber Sagnac filter which output spectrum was the uncorrThermally expanded core fibers were made by heating a singlemode fiber locally with hydrogenoxygen flame. An all fiber MZ filter was fabricated using the thermally expanded core fiber, and it was inserted into a Sagnac filter to make a new structure of tunable fiber Sagnac filter which output spectrum was the uncorrelated superposition between the Sagnac and the MZ interferences. With the new structure Sagnac fiber filter, a tunable erbiumdoped fiber laser was made and investigated experimentally. Tunable output was obtained by adjusting a polarization controller (PC) in the Sagnac interferometer. During the whole tuning process, the laser output wavelength could be tuned from 1 540.3 nm to 1 581.2 nm with the output power flatness better than 2 dB, 3 dB spectral linewidth narrower than 0.1 nm and optical signaltonoise extinction ratio higher than 45 dB..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1482 (2013)
Contrast of Vis/NIR Reflection and Diffuse Transmission in Detecting the SSC of Ganan Navel Oranges
XU Wenli, SUN Tong, WU Wenqiang, and LIU Muhua
The impact of using visible/near infrared reflection and diffuse transmission spectra to detect the soluble solids content of Gannan navel oranges was studied. Vis/NIR reflection and diffuse transmission spectra of 196 Gannan navel orange samples were acquired by using a QualitySpec spectrometer in the wavelength rangeThe impact of using visible/near infrared reflection and diffuse transmission spectra to detect the soluble solids content of Gannan navel oranges was studied. Vis/NIR reflection and diffuse transmission spectra of 196 Gannan navel orange samples were acquired by using a QualitySpec spectrometer in the wavelength range of 350~1 800 nm. Regarding these 196 samples, 147 samples were used as the calibration set to build calibration model, and balance 49 samples were used as the prediction set to validate model.Then a variety of pretreatment methods combined with partial least squares regression was used to develop the prediction models of SSC of navel oranges corresponding to a single spectrum and an average of three times spectra for Vis/NIR reflection and diffuse transmission spectra respectively. It is found that the diffuse transmission spectra prediction model is much better than the models of a single spectrum and an average of three times spectra. The partial least squares regression prediction model of Gannan navel orange based on the average of three times diffuse transmission spectra combined with multiplicative scattering correction pretreatment method performs the best, and the correlation coefficient and the root mean square errors in the calibration and prediction model are 0.980, 0.230°Brix and 0.949, 0.374°Brix respectively. So the average of multiple diffuse transmission spectra is more suitable for detecting the SSC of navel oranges..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1486 (2013)
Improving Spectrograph Accuracy by Bayesian Method
DONG Yuhang, and CEN Songyuan
Based on Bayesian condition probability formula anc combined with convolution theorem, a theoretical formula is derived that utilizes output and response functions to acquire input function with deconvolution. According to the performance parameter in spectrograph and pointspread functions of main sources(theoretical Based on Bayesian condition probability formula anc combined with convolution theorem, a theoretical formula is derived that utilizes output and response functions to acquire input function with deconvolution. According to the performance parameter in spectrograph and pointspread functions of main sources(theoretical formula of slit diffraction, grating diffraction and optical system aberration) the pointspread function of the spectrography is derived, and then this function is used to rectify the measuring result based on Bayesian deconvolution; using the difference of spectrum data before and after deconvolution, the concept “standard deviation of spectrum curve” is introduced to judge the data accuracy of the deconvolution output. The experimental result indicates that this method can effectively eliminate the influence of point spread function through iteration of system output, recover the original spectrum data from a “blurred” curve, and ultimately improve the accuracy of spectrograph..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1491 (2013)
Design of a Weighted Radiance of the LED Measuring System
LUO Yongjun, and MOU Tongsheng
The weighted radiance of LED is one of the most important parameter in photobiological safety evaluation of LED, so a special measurement system was established which combined of a CCD camera simulated of the human eye imaging and a spectrometer. Reference the testing requirements in the standards, the deficiencies of The weighted radiance of LED is one of the most important parameter in photobiological safety evaluation of LED, so a special measurement system was established which combined of a CCD camera simulated of the human eye imaging and a spectrometer. Reference the testing requirements in the standards, the deficiencies of the traditional luminance meter were analyzed theoretically and two typical LEDs were measured by the traditional luminance meter and the retina radiance meter. There were great differences between the weighted radiance in photobiological safety evaluation and the radiance in traditional optical measurements, and the special requirements made the traditional luminance meter cannot be able to measure the weighted radiance. Finally, the differences between the two luminance meters were introduced and test results were analyzed using the two luminance meters. The experimental results show that the weighted radiance of the white LED tested by the traditional luminance meter is 81.8 W/m2·sr, but the value is 137.0 W/m2·sr when the LED is tested by the novel system. Obviously, traditional luminance meter is not suitable for measuring the effective radiance and it will underestimate the hazard..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1496 (2013)
Study on Rapid Detection Method of Sunlight Specific Waveband Intensity
ZHANG Haihuia, LIANG Yana, HU Jina, LIU Zhengdaoa, ZHOU Qingzhena, and FAN Hongpanb
Different sunlight spectrua make different regulation on the photosynthesis and physiology of plants. The detection of different bands light intensity is the foundation of the highly efficient supplementary lighting. Because the existing specific band intensity detection instruments have the disadvantages of high cost Different sunlight spectrua make different regulation on the photosynthesis and physiology of plants. The detection of different bands light intensity is the foundation of the highly efficient supplementary lighting. Because the existing specific band intensity detection instruments have the disadvantages of high cost and easy to expand, a new method of rapid detection of specific waveband intensity was presented. Taking red and blue as an example, the percentage of specific waveband accounting for sunlight was obtained. By using Matlab, the least squares method was adpoted for fitting function, combining with the calculation formula of sun elevation angle, and a multiparameter coupling model between the percentage of specific waveband accounting for sunlight and the date, time, latitude and longitude was established. The specific waveband intensity was rapidly calculated by realtime detecting the intensity of sunlight. Experimental results showed that measurement error of the method is less than 4.5%, which can satisfy the need of light intensity detection of the subband of light filling system..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1501 (2013)
Optical System Design of the Optical Multifunction Detector
NIU Jin, WANG Jinsong, AN Zhiyong, and YANG Haining
An optical system of optical multifunctions detector was designed, which combined multiple detection functions such as laser beam quality analysis, photoelectric autocollimator, laser autocollimator, optical coherence detection as one. Its operating wavelength range was 300~1 700 nm, alignment accuracies was 2″ and An optical system of optical multifunctions detector was designed, which combined multiple detection functions such as laser beam quality analysis, photoelectric autocollimator, laser autocollimator, optical coherence detection as one. Its operating wavelength range was 300~1 700 nm, alignment accuracies was 2″ and angular resolution was 0.1″. One kind of parallel light beam expanding system and threeaxis system that had a long focus was designed, and a kind of removable toric lens telephoto with a central plane was adopted. The objective lens diameter was 75 mm, extend to 400 mm diameter. It enabled the optical system to achieve consistency, outgoing laser pointing and integrated multiparameter detection and had high degree of integration. Furthermore, it used the optical design software ZEMAX for system simulation and optimization. As a result, the modulation transfer functions at 50 lp/mm for the position of the focal length corresponding to different wavelengths are greater than 0.2n in the whole field of view. Then, a functional prototype was successfully developed, and processing equipment was tested after adjustment. Finally, the results show that it can get clear and accurate images in the focus range. The system satisfies the command of test requirements..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1507 (2013)
New Optical Large Field Receiving Technology in Laser Fuze
GAN Lin, ZHANG He, and ZHANG Xiangjin
As the limit of fuze space in conventional ammunition, it is impossible to arrange a number of laser receivers. Meanwhile, the system structure should be as simple as possible, so the traditional beam layout cannot be directly applied. Therefore, a new receiving system utilizing the technology of optical large field roAs the limit of fuze space in conventional ammunition, it is impossible to arrange a number of laser receivers. Meanwhile, the system structure should be as simple as possible, so the traditional beam layout cannot be directly applied. Therefore, a new receiving system utilizing the technology of optical large field rotary scanning was proposed. Based on the optical structure of laser fuze and the aspherical optical design theory, a set of multilevel optical focusing plastic lens were devised by using the application software called Zemax. Compared with the traditional singlestage focusing lens, the brightness of center irradiation was enhanced by nearly 8 times, the size of spot was decreased and the energy was centralized, which were shown by the simulation results. Then, a set of aspherical lens were developed as well as the related experiments. The results show that the echo energy of pulsed laser can be effectively converged and the detection range can be enhanced in the system described above. Finally, the large field detection whose circumferential view angle of the target is 360° is well realized..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1514 (2013)
Projection Optical System Design of Coaxial Dualband Infrared Based on Digital Micromirror Device
LIN Lina, SONG Shanshan, and WANG Wensheng
According to the requirements of the dynamic infrared scene simulator technology, a projection optical system of dualband infrared based on digital micromirror device was designed. The focal length of the projection system was 150 mm, the relative aperture was 1∶2 , the full field of view was 5.3° and the workinAccording to the requirements of the dynamic infrared scene simulator technology, a projection optical system of dualband infrared based on digital micromirror device was designed. The focal length of the projection system was 150 mm, the relative aperture was 1∶2 , the full field of view was 5.3° and the working wavelength covered the infrared middle wavelength (3~5 μm) and infrared long wavelength (8~12 μm).The system chose coaxial type and consisted of only three pieces of spherical lens and one projection prism. Ge, ZnS and ZnSe were used in the system. This system was simple, light weigh and low cost by introducing one binary surface. The designing results show: at the cutoff frequency 17 ly/mm and the image distance 5.6 mm, the modulation transfer function of middle wavelength is close to 0.7; the modulation transfer function of long wavelength is greater than 0.5; both are close to the diffraction limited curve. The system can meets the requirements of the overall design of the infrared scene simulator..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1519 (2013)
Design of Infrared Athermal System with Doublelayer Harmonic Diffractive Element
ZHANG Xinting, and AN Zhiyong
Considering the requirements of aberration and athermalized aberration, the concept of double harmonic diffractive element(HDE) was put forward based on the HDE. An infrared athermalized optical system that consists of two kinds of infrared materials composed AMTIRI and Ge was designed with work dualband of 3~5 μm andConsidering the requirements of aberration and athermalized aberration, the concept of double harmonic diffractive element(HDE) was put forward based on the HDE. An infrared athermalized optical system that consists of two kinds of infrared materials composed AMTIRI and Ge was designed with work dualband of 3~5 μm and 8~12 μm and the large relative aperture of 1.2. This system had stable performance in the range of (－40~+60)℃, was able to be applied in the dualband staring focal plane array detector with the pixel size of 25 μm and the number of pixel 640×480, and could distinguish the goals in 3 m when the role of distance was 2 km. It retained the unique properties of common diffractive lens, and could obtain the same focal power in a series of separate wavelength. So, it can greatly improve the diffraction efficiency of each band..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1524 (2013)
Light Field Rendering of Scintillator for XRay Imaging
WANG Xiaolong, LUO Shouhua, LI Guang, and YANG Jing
A new method that combining digital light field photography technology with the XRay scintillator imaging system is proposed. The scintillation luminescence principle and light intensity distribution are analyzed, a XRay light field imaging system is designed based on camera arrays, and the scintillation luminescenceA new method that combining digital light field photography technology with the XRay scintillator imaging system is proposed. The scintillation luminescence principle and light intensity distribution are analyzed, a XRay light field imaging system is designed based on camera arrays, and the scintillation luminescence model is simulated. Camera arrays in 3ds Max is used to capture the light from scintillator and get the images from different viewpoints. The light field data is generated that is similar to the data from microlens based system and get the images of arbitrary planes in the scintillator using the digital refocus algorithm. The simulation experiments show that XRay imaging system without using light field photography has a small depth of field; only a part of the scintillators are focused by optics and the defocused rest will decrease the image resolution; on the contrary, system with light field photography can extend the depth of field of the optical system to reduce the requirement of the scintillator thickness without changing the basic structure of the optical system; it can also get the image of the same resolution. The simulation provides theoretical basis for the establishment of real model..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1528 (2013)
Palm Vein Imaging Based on MultiIntensity Illumination
NI Xuxiang, GAO Shijie, WEI Keyu, WANG Wanshu, and CUI Yongsheng
Aiming at the problem of poor imaging quality due to the different thicknesses of the same palm, a method of getting the palm vein images was proposed based on multiillumination using nearinfrared region (NIR) light. The exponential relationship between illumination intensity and palm thickness was figured out accordAiming at the problem of poor imaging quality due to the different thicknesses of the same palm, a method of getting the palm vein images was proposed based on multiillumination using nearinfrared region (NIR) light. The exponential relationship between illumination intensity and palm thickness was figured out according to the optical model of the human palm and dynamic range of the CCD. Firstly, three different intensities of NIR light with the same wave length of 850 nm were be used as illumination in the experiment to obtain the palm vein images respectively. Secondly, palm vein images were divided into several subimages which are with high contrast. Next, the adaptive equalization was employed to enhance palm vein images. Finally, the method of weighting gradient splicing was applied to obtain the integrated palm vein images. Experimental result shows that the fusion method can improve the contrast of each part of palm vein images effectively compared with the transmission method with single illumination intensity and the reflection method. This method can be used in several application fields, such as venipuncture, biometrics and is of great value in the areas of identification recognition and the information security in the future..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 12, 1534 (2013)
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