Journals >Acta Photonica Sinica
Contents
2013
Volume: 42 Issue 5
26 Article(s)
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Research Article
Propagation of BesselGaussian Beam with Optical Vortices in Turbulent Atmosphere
WANG Haiyan, CHEN Chuanlin, DU Jialei, and BI Xiaowen
Based on the extended HuygensFresnel integral, the analytic expressions for BesselGaussian beams (BGBs) with optical vortices propagating in turbulent atmosphere are derived. The average intensity properties and the beam quality (Power in bucket) in the far field of BesselGaussian beams with optical vortices propagaBased on the extended HuygensFresnel integral, the analytic expressions for BesselGaussian beams (BGBs) with optical vortices propagating in turbulent atmosphere are derived. The average intensity properties and the beam quality (Power in bucket) in the far field of BesselGaussian beams with optical vortices propagating in turbulent atmosphere are investigated. It is found that intensity profiles of BesselGaussian beams experienced successive variations and the phase singularity rapidly fades away during propagating in turbulent atmosphere. The process is closely related with the number of topological charge, the beam′s waist width and the strength of atmospheric turbulence. The maintenance of singularity of vortex beams with larger topological charge in turbulent atmosphere is better than that for vortex beams with smaller topological charge. In addition, based on the theory of power in bucket, the influence of topological charge, the beam′s waist width and the strength of atmospheric turbulence on the beam quality of BesselGaussian beams is explored in detail..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 505 (2013)
Spin Hall Effect of the Reflected and Transmitted Vector Light Beam Between the Interfaces
DUAN Tao, XIE Xiaoping, DUAN Jie, QIAN Fengchen, and YAN Shaohui
The finite electromagnetic vector is achieved by factorizing into a mapping matrix and a Jones vector. The vectorial property can be described by a degree of freedom of the mapping matrix that can be determined by the azimuthal angle of a fixed unit vector with respect to the wave vector. The representation formalism oThe finite electromagnetic vector is achieved by factorizing into a mapping matrix and a Jones vector. The vectorial property can be described by a degree of freedom of the mapping matrix that can be determined by the azimuthal angle of a fixed unit vector with respect to the wave vector. The representation formalism of the reflected and transmitted vector light beams is theoretically developed between the interfaces. The transverse shift, which is correlative with the spin Hall effect, is discussed. The transverse shift of the linearly polarized light beam (σ=0) is zero. The transverse shift of the circularly polarized light beam (σ=±1) is maximum and the left and right circularly polarized light beam is the same.The dependence of transverse shift of the left circularly polarized light beam on the incidence angle is algo analyzed..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 511 (2013)
Femtosecond Laser Multibeam Interference Lithography Antireflective Microstructure on Silicon Surface
HE Fengtao, ZHOU Qiang, YANG Wenzheng, LONG Xuewen, BAI Jing, and CHENG Guanghua
In order to obtain uniform distribution silicon surface microstructure, a new method was proposed based on multibeam interference lithography to relaise the controlling of the distribution character of the microstructure. Femtosecond laser multibeam interference was formed by Spatial Light Modulator (SLM), and the unIn order to obtain uniform distribution silicon surface microstructure, a new method was proposed based on multibeam interference lithography to relaise the controlling of the distribution character of the microstructure. Femtosecond laser multibeam interference was formed by Spatial Light Modulator (SLM), and the uniform distribution multispots with the controllable period were generated. By using these multispots, the regular distribution concave structures were fabricated on silicon surface, and the distribution character and period was flexiblly controlled by shift the phase masks on SLM. The morphology and optical character of the microstructure were measured with Scanning Electron Microscopy (SEM) and spectrophotometer. Experimental results show that the closepacked concave structure with the period of about 3.3 μm can be fabricated on the silicon surface under special parameters (10× focusing lens, laser power of 25 mW, exposing time of 30 s) by loading the phase of 4facet pyramid lens with the base angle of 2°; the formed structure shows good effect of antireflection; its transmission at the near infrared band of 1.2~2 μm enhances 11.5% in comparison with the polished silicon..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 515 (2013)
All Fiberized Supercontinuum Laser Source Based on “Figure of Eight” Cavity Modelocked Yb Fiber Laser
QIAN Kai, WEI Kaihua, CHEN Tao, JIANG Peipei, CAI Shuangshuang, WU Bo, and SHEN Yonghang
An all fiberized novel subns pulsed fiber laser was presented based on the “figureofeight” cavity modelocking. The output pulse train was directed to pass a fiberized acoustooptic modulator based on firstorder diffraction to reduce the pulse repetition rate from 2.78 MHz to 93 kHz by adjustable pulse picking. AftAn all fiberized novel subns pulsed fiber laser was presented based on the “figureofeight” cavity modelocking. The output pulse train was directed to pass a fiberized acoustooptic modulator based on firstorder diffraction to reduce the pulse repetition rate from 2.78 MHz to 93 kHz by adjustable pulse picking. After the repetition rate decreasing, the peak power of the pulse laser was over 25 kW with the second amplifier, of which slope efficiency was 68.1%. Then the laser was used to excite bismuth doped silica fiber with optimization fiber length of 3m for supercontinuum generation. Finally the obtained laser spanned a spectral range of 1 100~2 200 nm with flatness better than 3 dB..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 521 (2013)
Fabrication and Laser Performance of Yb/P/Al Codoped Doubleclad Fibers
FENG Gaofeng, YANG Junyong, LU Weimin, GE Xiliang, LIU Wei, CHEN Tao, JIANG Peipei, and SHEN Yonghang
Yb/P/Al codoped silica glass preforms are fabricated by MCVD process combined with the solution doping technique. Highly and homogeneously doping of Yb3+ is realized by optimization of the core composition and fabrication process. The Yb2O3 concentration in preform core is up to ~4 wt.% and Yb3+ fluorescence lifetime aYb/P/Al codoped silica glass preforms are fabricated by MCVD process combined with the solution doping technique. Highly and homogeneously doping of Yb3+ is realized by optimization of the core composition and fabrication process. The Yb2O3 concentration in preform core is up to ~4 wt.% and Yb3+ fluorescence lifetime at 1080nm reaches 1 780 μs. Doubleclad fibers with octagonal inner cladding are successfully drawn from the preform, the fiber core diameter is 7.5 μm and the clad absorption coefficicent is up to ~5 dB/m@976 nm. The operation of the cladding pumped allfiber laser is demonstrated using Ybdoped doubleclad fibers. Fiber lasers with output power of 5.15 W and slope efficiency of 76% are obtained..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 526 (2013)
Modulation of Chirped Ultrashort Pulse in Dense and Resonant Medium
LI Bin, YU Xiangyang, CHEN Guojie, and CHEN Weicheng
According to the semiclassical theory of lightmatter interaction, the Bloch equations with chirped terms were established in a dense twolevel medium, and an accurate and efficient fourthorder RungeKutta method was applied for solving the equations. After numerical simulation, the interactions between a chirped ultAccording to the semiclassical theory of lightmatter interaction, the Bloch equations with chirped terms were established in a dense twolevel medium, and an accurate and efficient fourthorder RungeKutta method was applied for solving the equations. After numerical simulation, the interactions between a chirped ultrashort pulse and dense resonant twolevel medium were investigated, and the influences of localfield effects and chirp on Bloch vectors were gained. The numerical results show that, the evolutions of Bloch vectors and the final state of inversion are strongly modulated by the localfield effects correction coefficient and chirp parameter, which provides a method to achieve stable population inversion of control by adjusting the linear chirp parameter and local field correction coefficient..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 531 (2013)
Diffraction Radiation of Subwavelength Metallic Grating
ZHANG Ping, DONG Liang, ZHANG Yaxin, and ZHOU Jun
The mechanism and characters of diffraction radiation of subwavelength metallic grating structure are analysed and discussed. Using the three dimensinal particleincell simulation, the contour map of electric field of the grating is obtained excited by moving electron bunch. Combined with the Brillouin diagram, it shoThe mechanism and characters of diffraction radiation of subwavelength metallic grating structure are analysed and discussed. Using the three dimensinal particleincell simulation, the contour map of electric field of the grating is obtained excited by moving electron bunch. Combined with the Brillouin diagram, it shows that the diffraction radiation in the upper and lower halfspace can also be explained by the formula of SimthPurcell radiation. Then, the influences of the gap width and the thickness of the grating to the diffraciton radiation are also analyzed. Based on the comparison for the asymmetric graing excited by different beam energies, the physical mechanism of the diffraction radiation in the lower halfspace are discussed in further. For asymmetric grating, the diffraciton radiation in the lower halfspace are determined by the velocity of elelctron and the grating period, and by the radiation in the upper halfspace..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 537 (2013)
Analysis and Simulation of Link Power and Commincation Performance in Spaceground Optical Communication
YU Lintao, SONG Lu, HAN Chen, and ZHOU Dechun
The influences of main parts of an apparatus and channel to power of communication laser on spaceground optical communication slant link were analyzed. Based on the formula for signaltonoise ratio of receiving detector and bit error rate of communication, the simulation system of spaceground optical communication wThe influences of main parts of an apparatus and channel to power of communication laser on spaceground optical communication slant link were analyzed. Based on the formula for signaltonoise ratio of receiving detector and bit error rate of communication, the simulation system of spaceground optical communication was established. Using the simulation system, the highest communication rates as to the different atmospheric visibilities were analyzed, the assumptions that bit error rate is superior to 10－7, the minimum transmitter power and the maximum communication distance were discussed in order to achieve the communication rate to 1.5 GHz and bit error rate is superior to 10－7. The result indicates that influence of the atmospheric visibility to the bit error rate is more obvious, when the transmitter power is greater..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 543 (2013)
Preparation and Characterization of Thin Flexible Image Fiber by Using Acidleaching Method
ZHOU Dechun, CUI Yuan, and YU Fengxia
The acidleaching image optical material, which has many virtues such as fine single fiber diameter, best softness properties and high resolution, has been widely applied in high image definition instruments and industrial automatic detection fields. Using the host glass material, the experiments on high optical qualitThe acidleaching image optical material, which has many virtues such as fine single fiber diameter, best softness properties and high resolution, has been widely applied in high image definition instruments and industrial automatic detection fields. Using the host glass material, the experiments on high optical quality performs with matched physicochemical properties preparation, fiber pulling and arranging and acid dissolution for rigid image fiber were carried out. Resolution of the flexible image fiber, spectral transmissivity and dark fiber was analyzed and characterized. The experimental results show that the preparation produce of the material makes a breakthrough in traditional image fiber's production technique and the structure and technique of the image fiber are innovated..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 548 (2013)
Fabrication of Yb3+/Al3+ Codoped Largemodearea Photonic Crystal Fiber Based on Powder Sintering Technology
LIU Jiantao, ZHOU Guiyao, and XIA Changming
Based on powder sintering technology, Yb3+/Al3+ codoped silica rods are prepared, and the concentration of Yb3+ is up to 12 000 ppm (wt). Then, with the Yb3+/Al3+ codoped silica rods as core materials, highly doped Largemodearea Photonic Crystal Fibers (LMAPCF) are fabricated by stackdraw method. The mode area caBased on powder sintering technology, Yb3+/Al3+ codoped silica rods are prepared, and the concentration of Yb3+ is up to 12 000 ppm (wt). Then, with the Yb3+/Al3+ codoped silica rods as core materials, highly doped Largemodearea Photonic Crystal Fibers (LMAPCF) are fabricated by stackdraw method. The mode area can reach 550 μm2, and the mode field diameter is 26 μm. The results indicate that the fiber has a broad absorption band in the near infrared wavelength (850~1 033 nm), and the main peak is at the wavelength of 976 nm where the absorption loss is higher than 10 dB/m; when the fiber is pumped by the laser with a wavelength of 971 nm, there exists a Gaussian fluorescence peak in the wavelength range of 1 150~1 125 nm, with a peak value of 1 088 nm and a halfline width of 45 nm..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 552 (2013)
Preparation and Performance Testing of Metallic Biologic Particles
SUN Dujuan, HU Yihua, GU Youlin, WANG Yong, and LI Le
Fousing on demands in military and civilian fields for new coated composite functional material, farinas, using as nucleus and metallized by chemical plating copper method, are enwraped by cupreous crusts and made into metallic farinas. By using scanning electron microscope, Fourier transform infrared spectrometer and Fousing on demands in military and civilian fields for new coated composite functional material, farinas, using as nucleus and metallized by chemical plating copper method, are enwraped by cupreous crusts and made into metallic farinas. By using scanning electron microscope, Fourier transform infrared spectrometer and microwave testing system, metallic farinas′ structure characteristic, electromagnetic properties in infrared and microwave band are tested. The SEM picture shows that metallic farinas have complete morphology, without fracture or deformation. Their cupreous crusts′ thickness is homogeneous, about 1 μm, and have compact structure. The results of infrared and microwave band experiments show that metallic farinas′ electromagnetic properties in infrared and microwave band are determined by their cupreous crusts, reflecting and absorbing infrared and microwave intensively. Metallic farinas, whose metallic crusts have strong attenuation capability and fraina nuclus are lightweight, are practicable to be used as functional material in infrared and microwave band..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 555 (2013)
Effects of HeNe Laser and Enhanced UltravioletB Radiation on TaRAN1 Protein in Wheat
MAO Xiaofang, and HAN Rong
When the seedlings of wheat‘ML7113 ’were exposed to both HeNe 1aser irradiation(5 mW·mm－2) and enhanced UVB radiated rdiation(10.08 kJ·m－2·d－1). 6 days after the extraction of the wheat leaves the total protein and TaRAN1 of protein in each treatment group，identification of target proteins by SDSPAGE When the seedlings of wheat‘ML7113 ’were exposed to both HeNe 1aser irradiation(5 mW·mm－2) and enhanced UVB radiated rdiation(10.08 kJ·m－2·d－1). 6 days after the extraction of the wheat leaves the total protein and TaRAN1 of protein in each treatment group，identification of target proteins by SDSPAGE of their conduct the preliminary test and Western Blot and Coomassie brilliant blue method to measure the protein content of four different treatment groups TaRAN1 to do further analysis. The results showed that, enhanced UVB radiation makes wheat TaRAN1 protein electrophoresis band color deepened and contents increased significantly; Separate HeNe laser processing, protein electrophoresis with narrow lighter in color and measured the protein content is significantly reduced, showing inhibition; With HeNe laser irradiation and UVB after radiation treatment, The protein content was significantly lower than the enhanced UVB radiation treatment group, while no obvious difference with the control group. Explain the enhanced UVB radiation, the wheat TaRAN1 protein may be involved in the antistress responses of plants..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 559 (2013)
Guide Modes in Threedimensional Topological Insulator Waveguide Induced by Magnetic Fields
XU Yi, HE Ying, and YANG Yanfang
A magnetic quantum well created by putting two ferromagnetic metal stripes on the threedimensional topological insulator is investigated. The incident electron waves are confined in the quantum well by controlling the incident energy. The dispersion equation of the waveguide is obtained with the continuity of the waveA magnetic quantum well created by putting two ferromagnetic metal stripes on the threedimensional topological insulator is investigated. The incident electron waves are confined in the quantum well by controlling the incident energy. The dispersion equation of the waveguide is obtained with the continuity of the wave functions. The graphical method is applied to solve this equation since it is a transcendental equation, of which the solution can not be obtained with analytic method. Whether the energy of the incident electrons is higher than the magnetic barrier or not, the electron waveguide can be formed. The waveguide supports the fundamental mode for the higher incident electron energy. The order of the modes increases with the increasing electron energy. The number of the guided modes decreases for the lower incident electron energy. The probability density of spatial distribution is studied. It shows that the threedimensional topological insulator waveguide induced by magnetic fields can confine electrons well and the lower guided modes can confine electrons better than the higher guided modes. Moreover, the function of the probability current density distribution in the waveguide is also presented..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 564 (2013)
Preparation and Characteristic of Secondprinting Type Carbon Nanotube Cathode for Triode Field Emission Display
LI Yukui, WANG Fengge, ZENG Fanguang, and LU Wenke
With screenprinting technique, a novel carbon nanotube (CNT) cathode preparation method was developed. Using doublewalled CNT as primary material, the mixing CNT paste was fabricated, in which the minute Ag particles were included. On the mixing CNT paste printed on the conducting electrode surface, the common CNT paWith screenprinting technique, a novel carbon nanotube (CNT) cathode preparation method was developed. Using doublewalled CNT as primary material, the mixing CNT paste was fabricated, in which the minute Ag particles were included. On the mixing CNT paste printed on the conducting electrode surface, the common CNT paste was prepared. The baked CNT pastes were sintered simultaneously in the chain sintering furnace to remove the organic solvent, and the secondprinting type CNT cathode was formed after the proper overvoltage posttreatment process was conducted. With the fabricated secondprinting type CNT cathode, the field emission characteristics could be improved significantly. The triode secondprinting CNT cathode field emission display was fabricated, which exhibited higher luminous brightness and better luminescence image brightness uniformity. Comparing with the common CNT cathode field emission display, the turnon electric field could be reduced from 2.15 V/μm to 1.75 V/μm and the maximum field emission current would be enhanced from 735.8 μA to 1 588.5 μA. The developed preparation method of CNT cathode possessed considerable potential for practical applications and the fabrication cost was low..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 570 (2013)
A Uband Lefthanded Metamaterial Based on Twolayered SRR Structure
YI Qiang, ZHOU Fukun, and LUO Xingfang
A Uband lefthanded metamaterial is designed and simulated to obtain the scattering parameters after the dimensions are estimated according to the transimission line theory of the lefthanded metamaterial. Furthermore, the properties of transmission and the negative electromagnetic parameters are analyzed after effectA Uband lefthanded metamaterial is designed and simulated to obtain the scattering parameters after the dimensions are estimated according to the transimission line theory of the lefthanded metamaterial. Furthermore, the properties of transmission and the negative electromagnetic parameters are analyzed after effective permittivity; effective permeability and refraction index are calculated by the Smith parameter retrieval method. The results show that the proposed lefthanded metamaterial structure behaviours the negative refraction characteristic while the real parts of effective permittivity and effective permeability are both negative in 48.8~59.9 GHz band. Thus, the existence of the lefthanded metamaterial in Uband is demonstrated，and it is of great reference significance to research on metamaterials in higher band..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 576 (2013)
Discrimination of Adulterated Milk Using NPLSDA Combined with Twodimensional Correlation Nearinfrared Spectroscopy
YANG Renjie, LIU Rong, XU Kexin, and YANG Yanrong
In order to develop a rapid, costeffective and highthroughput analysis method for detecting adulterants in milk, adulterated milk discriminant models are established by combing twodimensional (2D) correlation nearinfrared spectroscopy with multiway partial least squaresdiscriminant analysis (NPLSDA). 40 adulteraIn order to develop a rapid, costeffective and highthroughput analysis method for detecting adulterants in milk, adulterated milk discriminant models are established by combing twodimensional (2D) correlation nearinfrared spectroscopy with multiway partial least squaresdiscriminant analysis (NPLSDA). 40 adulterated milk samples with melamine（0.01~3 g/L）and 40 adulterated milk samples with urea （1~20 g/L）are prepared respectively, then the absorption spectra of all samples are measured. Based on quantization of 2D correlation spectrum, the NPLSDA models of ureatainted milk, melaminetainted milk and two types adulterated milk are constructed. The recognition rates of unknown samples are 95%, 90%, and 92.5% by calibration models individually. At the same time, PLSDA and OPLSDA models are established. The results show that NPLSDA model has better predictive ability than PLSDA model and OPLSDA model, and this method can also be applied to other food safety detection areas..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 580 (2013)
Spectrophotometer for Biochemical Analyzer Based on Automatic Adjustment of CCD Integration Time
REN Zhong, LIU Guodong, and HUANG Zhen
Although the spectrophotometer for biochemical analyzer (BCA) has been applied to the properties analysis of biological samples including blood, some factors result in reducing the spectral measurement accuracy in practice. For example, the spectral absorbances are different for the various components in sample at difAlthough the spectrophotometer for biochemical analyzer (BCA) has been applied to the properties analysis of biological samples including blood, some factors result in reducing the spectral measurement accuracy in practice. For example, the spectral absorbances are different for the various components in sample at different absorption wavebands, especially at the larger energy attentuation waveband and noncharacteristic absorption waveband, which leads to the signals of strong absorbances are very large, but for weak absorbances, the singals are very small even covered by noises. Additionally, various noises generated by electronic devices and straylight also bring serious interference for system. To solve these drawbacks above mentioned, an optimize algorithm of automatic adjustment of linear charge coupled devices(CCD) integration time combined with time and data division was used to realize the separate exposure for strong absorption and weak absorption spectrum, which improved the weak signals under the condition of strong signals were normal. Experiments were done by using a custombulit high resolution spectrophotometer for BCA based on CzernyTurner splittinglight monochrometer and linear CCD. Experimental results demonstrated that the improved method effectively enhanced the spectral measurement accuracy, system performance and signaltonoise ratio. In additon, the spectral range of this spectrophotometer for BCA can reache 300~800 nm, wavelength resolution less than 2 nm..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 586 (2013)
Nondestructive Detection of Firmness of Hami Melon by Hyperspectral Imaging Technique
LI Fengxia, MA Benxue, HE Qinghai, Lv Chen, WANG Bao, and TIAN Hao
In order to detect firmness of hamimelon, a method based on hyper spectral imaging technique is proposed. Effects of different wave bands, different preprocessing methods, different spectral correction methods and different quantitative methods on the predictive accuracy of the model for firmness are compared and analyIn order to detect firmness of hamimelon, a method based on hyper spectral imaging technique is proposed. Effects of different wave bands, different preprocessing methods, different spectral correction methods and different quantitative methods on the predictive accuracy of the model for firmness are compared and analyzed. Experimental results show that in the spectral region between 500 to 820 nm, the partial least square model of the first derivative spectrum processed by standard normal variate gives the best prediction of firmness, with a correction sample correlation coefficient of 0.873, a lower root mean square errors of correction of 4.18 N, a prediction sample correlation coefficient of 0.646 and a root mean square errors of prediction of 6.40 N. The research indicutes that the hyperspectral imaging technique can be used for the nondestructive detection of firmness of hami melon..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 592 (2013)
Synthesizing Algorithm for LED Standard Solar Spectrum Lamp
ZHANG Yiwen, XU Lin, and WAN Song
In order to achieve a LEDbased solar simulator or a standard spectrum lamp with high stability and good spectral matching that can be used in measurement, a method is proposed to accurately simulate the spectral power distribution (SPD) of AM1.5 by adopting many different peak wavelength LEDs. Least square (LS) methodIn order to achieve a LEDbased solar simulator or a standard spectrum lamp with high stability and good spectral matching that can be used in measurement, a method is proposed to accurately simulate the spectral power distribution (SPD) of AM1.5 by adopting many different peak wavelength LEDs. Least square (LS) method and the characteristics of Gaussian distribution are considered during the process of simulation. This approach theoretically achieves a spectral synthesize in order to guide the LED types selection and the drive current value. Experimental result proves its feasibility and show that: in the range of 300~1 100 nm, the spectral mismatch error is less than ±2.76%, and less LED species are adopted. This algorithm can accurately distinguish the absorption valleys of standard solar spectrum AM1.5. When applied to AM0, it results in the spectral mismatch less than ± 1.67%. For engineering application, the algorithm gives a good guiding significance to access standard solar spectrum lamp..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 596 (2013)
A Method for Evaluate the Effects of Compression to Image Feature Extraction
WANG Yu, YANG Xiuce, and LI Chenzhao
Based on analysis of the effects of compression to image feature extraction, a quantitive method is proposed to evaluate the effects of compression to image feature extraction. The feature of image is extracted, and change detection method is used to statist the effect of compression. The compression test used JPEG2000Based on analysis of the effects of compression to image feature extraction, a quantitive method is proposed to evaluate the effects of compression to image feature extraction. The feature of image is extracted, and change detection method is used to statist the effect of compression. The compression test used JPEG2000 to SPOT5 image showed that the proposed method can obtain the coherenceedge curve, and has strong ability to remove noise; line feature extraction results are applicable to feature change comparison; the method can also reflect the different image information loss of multiple compressed ratio, the higher of line feature change rate, and the more of compression image information loss..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 601 (2013)
Auto Focusing Algorithm Based on Largest Gray Gradient Summation
ZHANG Laixian, SUN Huayan, GUO Huichao, and FAN Youchen
The principle of defocused imaging was introduced based on optical system. The defects of classical auto focusing algorithms based on gray gradient were presented, which were not considering all the gray gradient and affected by noise easily. According to the defects of classical algorithms, a new auto focusing algoritThe principle of defocused imaging was introduced based on optical system. The defects of classical auto focusing algorithms based on gray gradient were presented, which were not considering all the gray gradient and affected by noise easily. According to the defects of classical algorithms, a new auto focusing algorithm based on largest gray gradient summation was proposed, which was realized through adding the product of the maximum and the difference of the maximum and the minimum of the eight neighborhood gray gradient of each pixel in the selected auto focusing region. The principle of restraining noise of the new algorithm was discussed. The principle and progress of adaptive variable step climbing algorithm for focusing position searching were introduced. At last, experiments were carried out to test the performance of the new algorithm. Firstly, by calculating the definition value of the original and Gaussian noise added sequences images using new algorithm and classical algorithms, and comparing the results, the advantage of restraining noise of the new algorithm was proved, for using the new algorithm, the definition evaluation of noisy image was calculated better compared to all the other algorithms. Secondly, experiments of auto focusing using different algorithms were carried out, and the results showed that using classical algorithms might focus wrong, while the new algorithm could focus correct and rapidly, which was an obvious advantage comparing to classical algorithms..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 605 (2013)
Dispersion Characteristics of Total Reflection Tunnel in 1D Photonic Crystal
LIU Qineng, and LIU Qin
Using the dispersion relation and the characteristic matrix method, dispersion characteristics of the total reflection tunnel of TE wave and TM wave in 1D photonic crystal are studied. The total reflection tunnel frequency center decreases with the increase of the dispersion intensity, and the total reflection tunnel fUsing the dispersion relation and the characteristic matrix method, dispersion characteristics of the total reflection tunnel of TE wave and TM wave in 1D photonic crystal are studied. The total reflection tunnel frequency center decreases with the increase of the dispersion intensity, and the total reflection tunnel frequency width increases with the dispersion of dispersion intensity. The total reflection tunnel frequency center increases with the dispersion of incident angle, and the total reflection tunnel frequency width decreases with the dispersion of incident angle. These findings expand the understanding of the total reflection tunnel of TE wave and TM wave in 1D photonic crystal..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 611 (2013)
A Novel Defect Mode of Singlenegative Media Photonic Crystal with Anisotropic Defect
LI Jianming
A kind of zerophaseshift gap appears in the onedimensional photonic crystal composed ofalternate epsilonnegative materialand munegative material, and the gap does not vary with electromagnetic wave incident angle and polarization direction. To tune the defect mode frequency, a layer of anisotropic media is introduA kind of zerophaseshift gap appears in the onedimensional photonic crystal composed ofalternate epsilonnegative materialand munegative material, and the gap does not vary with electromagnetic wave incident angle and polarization direction. To tune the defect mode frequency, a layer of anisotropic media is introduced into the center of that photonic crystal. The transmission spectra are investigated by Berreman 4×4 matrix. The result indicatesthat frequency of defect mode can be tuned by rotating the anisotropic media around zaxis in laboratory coordinate, and does not changed by different incident angles. These phenomena can be applied to tunable single tunnel omnidirectional filter in light wave..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 615 (2013)
Scheme of Twoway Quantum Teleportation and Security
YANG Youfeng, and YE Zhiqing
A scheme of twoway teleportation is proposed, with Bell entangled state as Quantum Channel (QC). Firstly, two sides of communication(Alice and Bob), share two EPR entangled states. After communication, Alice and Bob perform Bellstate joint measurements to their own qubits respectively, and announce the measured resulA scheme of twoway teleportation is proposed, with Bell entangled state as Quantum Channel (QC). Firstly, two sides of communication(Alice and Bob), share two EPR entangled states. After communication, Alice and Bob perform Bellstate joint measurements to their own qubits respectively, and announce the measured results via Classical Channel (CC). Then according to the measured results, Alice and Bob make relevant unitary transformations, namely, its own party can reproduce the opposite quantum state information, and thus the twoway teleportation is realized. In order to enhance the security of twoway teleportation, and the analysis result indicates that the system′s security will strengthen with the increase of the control particles, but the security will not strengthen when the control particles increase to a certain number..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 619 (2013)
Probabilistic Teleportation of Twoatom Entangled State via Fouratom Cluster State
YU Lizhi, and WU Tao
A scheme for teleporting an unknown two twolevel atoms entangled state via four identical twolevel atoms nonmaximally entangled Cluster state as quantum channel is proposed. In the scheme, the receiver Bob can reconstruct the original state with a certain probability by introducing an auxiliary atom and operating unA scheme for teleporting an unknown two twolevel atoms entangled state via four identical twolevel atoms nonmaximally entangled Cluster state as quantum channel is proposed. In the scheme, the receiver Bob can reconstruct the original state with a certain probability by introducing an auxiliary atom and operating unitary transformations according to the sender Alice′s measurement results, and the successful probability is determined by the smallest two coefficients′ absolute values of the Cluster state. The considerable advantage of the scheme is that a nonmaximally entangled Cluster state is employed as quantum channel, thus, the scheme can greatly reduce the amount of entanglement resources and need less classical bits. If a maximally entangled Cluster state is employed as quantum channel, the probabilistic teleportation scheme becomes usual teleportation, of which the successful probability is 100%..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 623 (2013)
Effect of the Stark Shift on Atom Entanglement in a Two Identity Atoms TavisCummings Model
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Two identity atoms initially in a maximally entangled state, the fields in the singlemodel thermal fields, and the TavisCummings (TC) model are studied. Effects of Stark shift added in the Hamilton of the two identity atoms TC system on the decoherence time of atomic entanglement are analyzed. The results show thatTwo identity atoms initially in a maximally entangled state, the fields in the singlemodel thermal fields, and the TavisCummings (TC) model are studied. Effects of Stark shift added in the Hamilton of the two identity atoms TC system on the decoherence time of atomic entanglement are analyzed. The results show that the two atoms evolve periodically into a disentangled separable state when Stark shift is not considered; the two atoms keep longlived entanglement when Stark shift is considered..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 42, Issue 5, 627 (2013)
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