Journals >Laser & Optoelectronics Progress
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2010
Volume: 47 Issue 7
23 Article(s)
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Fiber Optics and Optical Communications
Acoustic Sensitivity of Interferometric Fiber-Optic Mandrel Hydrophone
Zhou Wei, Zhou Hongpu, Zhang Min, and Liao Yanbiao
The acoustic sensitivity of mandrel interferometric fiber-optic hydrophone with three layers(coated layer,flexible tube,mandrel) was analyzed. Modeling was built with three-dimensional elasticity analysis. Results show that the major factors which influence the acoustic sensitivity of the hydrophone are elastic modulusThe acoustic sensitivity of mandrel interferometric fiber-optic hydrophone with three layers(coated layer,flexible tube,mandrel) was analyzed. Modeling was built with three-dimensional elasticity analysis. Results show that the major factors which influence the acoustic sensitivity of the hydrophone are elastic modulus,wall thickness,outer radius of the tube,and sensing fiber′s length and diameter. Young′s modulus,Poisson′s ratio and thickness of encapsulation layer and mandrel have little effect on the acoustic sensitivity. A number of hydrophone samples were produced. The theoretical value of their acoustic sensitivity is -150.7 dB (re rad/μPa),and the average measured values is -151.3 dB (re rad/μPa). The range of measured values is -151.9~-150.5 dB (re rad/μPa),the difference between theoretical value and the measured value is less than 1.2 dB(re rad/μPa). Experiments also show that encapsulation process of packaging has some influence on the acoustic sensitivity..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 70601 (2010)
Novel Transmissive Gires-Tournois Interleaver Based on Composite Coupler and Its Dispersion Compensation
Wang Xiulin, Zhang Yu, Huang Wencai, Xu Huiying, and Cai Zhiping
The transmissive Gires-Tournois etalon (GTE) is proposed based on composite couplers. By combining such GTEs with Mach-Zehnder interferometer (MZI),we obtain a new interleaver. The output expression is derived and numerical simulation is performed. The simulation indicates that it has good passband flatness (flat-top),The transmissive Gires-Tournois etalon (GTE) is proposed based on composite couplers. By combining such GTEs with Mach-Zehnder interferometer (MZI),we obtain a new interleaver. The output expression is derived and numerical simulation is performed. The simulation indicates that it has good passband flatness (flat-top),large isolation,wide passband and stopband bandwidths. By optimizing the spectrum it shows that when the sum of cavities of GTEs is fixed,the larger the passband bandwidth gets,the smaller the isolation will be,i.e.,isolation and bandwidth are incompatible. However,this contradiction can be overcome by increasing the sum of cavities,i.e.,interleaver′s spectral performance can be enhanced by increasing cavities. Compared with the ring resonator assisted interleaver,the proposed interleaver can achieve rectangle spectrum without using the phase shifter and its spectrum is uniform in the whole wavelength band. Further more,a set of cascaded ring resonators is proposed as the dispersion compenastor to overcome the dispersion of the interleaver. Dispersion compensation ability is very good and can be enhanced by increasing the number of ring resonators..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 70602 (2010)
Geometric Optics
Study of Temperature Distribution Function of Star Sensor
Tan Wei, Yang Jiankun, Zhu Mengzhen, Shen Dingyi, Wang Xiaobing, and Zen Wenfeng
The relation of temperature level function with the outside surface solar absorptivity,outside surface emissivity,inside surface emissivity,angle of sun incidence is fitted respectively. The relation of temperature difference function with the thermal joint conduction and the heat conduction of drawtube is fitted respeThe relation of temperature level function with the outside surface solar absorptivity,outside surface emissivity,inside surface emissivity,angle of sun incidence is fitted respectively. The relation of temperature difference function with the thermal joint conduction and the heat conduction of drawtube is fitted respectively. The curve fitting function formula accords with the theory. The result shows that when the outside surface solar absorptivity and emissivity change from 0.05 to 1,the changes of temperature level in the star sensor system are 149.89 ℃ and 147.44 ℃. The effect of the inside surface emissivity on the temperature level is obviously smaller than that on the outside. When the angle of sun incidence is ±11.97°,the temperature level is the highest. The temperature difference effect of the thermal joint conduction and the heat conduction of the drawtube has a non-sensitivity region. When the thermal conductivity is more than 60 W/(m·K) and 200 W/(m·K) respectively,the thermal conductivity effect on the temperature difference is small..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 70801 (2010)
Image Processing
Application of Two-Dimensional Continuous Wavelet Transform in Demodulating Fringe Pattern with Two Frequency Components
Cai Yixiang, Chen Wenjing, Li Sikun, Zhao Yue, and Xu Luopeng
Based on the basic principle of wavelet transform,the shortage of one-dimensional complex Morlet wavelet transform in demodulating the tilt fringe pattern with two carrier frequencies was analyzed. Then the method of two-dimensional (2-D) fan wavelet made up of a series of 2-D complex Morlet wavelet was proposed to demBased on the basic principle of wavelet transform,the shortage of one-dimensional complex Morlet wavelet transform in demodulating the tilt fringe pattern with two carrier frequencies was analyzed. Then the method of two-dimensional (2-D) fan wavelet made up of a series of 2-D complex Morlet wavelet was proposed to demodulate such patterns. We compared the two methods through processing deformed fringe patterns with two carrier frequencies. The results show 2-D fan wavelet has better ability to obtain the useful information because it can analyze the signals by adjusting both the scaling factor and rotation angle to reach the optimal match between the singles and wavelet functions. That is,2-D Fan wavelet has advantages to dispose two-frequency components grating patterns because of its multiple-directional property..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 71001 (2010)
Instrumentation, Measurement and Metrology
FFT Phase Detection Method for Self-Mixing Laser Diode Micro-Displacement Measurement
Zhang Zhaoyun, 2Gao Yang, Zhao Xinghai, and Zhao Xiang
Fast Fourier transform (FFT) phase detection method is used to analyze the self-mixing interference signal,without increasing the system′s complexity. By this technique,the self-mixing laser diode (SMLD) micro-displacement measurement technology can obtain nanometre measurement precision. The principle of the self-mixiFast Fourier transform (FFT) phase detection method is used to analyze the self-mixing interference signal,without increasing the system′s complexity. By this technique,the self-mixing laser diode (SMLD) micro-displacement measurement technology can obtain nanometre measurement precision. The principle of the self-mixing laser micro-displacement measurement technology is analyzed. The FFT phase detection signal processing is introduced. The optical feeding level,Fourier transform periods length,target moving speed and target vibrating range are analyzed by simulation. Simulation and experimental results show that,this method is suitable to measure target with low speed and small moving range. Choosing proper optical feeding level and Fourier transform periods length,the SMLD micro-displacement sensing technology can obtain measurement precision less than 10 nm..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 71201 (2010)
Integrated Optics
Negative Goos-Hnchen Shifts of Two-Dimensional Photonic Crystal
Dai Qiaofeng
The Goos-Hnchen (GH) shift is investigated for a Gaussian beam reflected by a two-dimensional photonic crystal using the transfer matrix method. With frequencies in stop band,the GH shift is small for a perfect photonic crystal,while it is several times of lattice constant for photonic crystal with adjusted radius of The Goos-Hnchen (GH) shift is investigated for a Gaussian beam reflected by a two-dimensional photonic crystal using the transfer matrix method. With frequencies in stop band,the GH shift is small for a perfect photonic crystal,while it is several times of lattice constant for photonic crystal with adjusted radius of air hole in surfaced layer. The property is helpful to improve the coupling efficiencies between photonic crystals and other micro-/nano-optical devices..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 71301 (2010)
Lasers and Laser Optics
Multiple Transverse Mode Laser Oscillator of High Repetition-Rate Nd:Glass Shock Treatment Installation
Yang Xinghua, Guan haibing, Wu Hongxing, Guo Dahao, Zhang Yongkang, Ren Xudong, and Lu Jinzhong
Multiple transverse mode laser oscillator of high repetition-rate Nd:glass shock treatment installation is disscussed. The design of high repetition-rate Nd:glass laser shock processing and the parameters of various optical elements are given.The laser output energy,pulse width and amplified spontaneous emission (ASE) Multiple transverse mode laser oscillator of high repetition-rate Nd:glass shock treatment installation is disscussed. The design of high repetition-rate Nd:glass laser shock processing and the parameters of various optical elements are given.The laser output energy,pulse width and amplified spontaneous emission (ASE) are measured at the single frequence and 0.5 Hz frequence. The results show that the laser output energy can reach more than 40 J,with laser width of 22 ns and ASE of about 16 mJ,and the laser can be used for laser shock processing..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 71402 (2010)
Pyroelectric Detecting of High-Repetition-Frequency Pulse Laser
Zhang Lei, Zhao Jun, Yang Pengling, Shao Bibo, Wang Zhenbao, and Yan Yan
Based on the working principle of pyroelectric detector,the transient response characteristics to the pulse laser of the detector were researched. The working model of pyroelectric detector single pulse radiation was built,and the model of the response used in practical application was simulated according to the materiBased on the working principle of pyroelectric detector,the transient response characteristics to the pulse laser of the detector were researched. The working model of pyroelectric detector single pulse radiation was built,and the model of the response used in practical application was simulated according to the material and structure parameters. The influences of the detector material properties and structural parameters on the detector response characteristics were also analyzed through simulation,in which the influences of electricity time-constant and the hot time-constant were studied mostly. Signal extraction circuits for high-repetition-frequence pulse were designed. Finally,a number of repetition frequency laser radiation experiments on the pyroelectric detector and signal extraction circuits designed were carried out. The comparative experiments on frequency response and pulse width of the detector were completed,and the feasibility of applying the pyroelectric detector to energy measurement of high-repetition-frequency and narrow pulse laser was verified. The measuring range and other index marks of the detecting unit were given..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 71404 (2010)
Nonlinear Optics
Theoretical Analysis on Chirp Matched Optical Parametric Chirped Pulse Amplification
Li Xianhua, Zeng Shuguang, Zhang Bin, Sun Nianchun, and Sui Zhan
Chirp matched optical parametric chirped pulse amplification method (OPCPA) has been proposed by studying the variation of OPCPA gain spectrum with the pump optical center wavelength. Taking nonlinear KDP crystal as an example,the temporal and spectral gain characteristics of the chirp matched and mismatched OPCPA methChirp matched optical parametric chirped pulse amplification method (OPCPA) has been proposed by studying the variation of OPCPA gain spectrum with the pump optical center wavelength. Taking nonlinear KDP crystal as an example,the temporal and spectral gain characteristics of the chirp matched and mismatched OPCPA methods have been studied. Furthermore,the changes of the temporal and the spectral profiles before and after the OPCPA have been analyzed in details. The results show that the gain narrowing phenomenon becomes significant for the chirp mismatched case. However,the gain spectrum width is greatly increased by using chirp matched method,eliminating the gain narrowing phenomenon..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 71901 (2010)
Optical Devices
Optimized Research on Conformal-Coating Technology of Power White LEDs
He Yuan, Rao Haibo, Ju Jianjun, Hu Yue, Shen Fahua, Gao Hansong, and Wan Yuantao
Conformal-coating technology of power white LEDs uses PVA+ADC water-solution compounding yellow phosphor to coat on the surface of the die,then gets planar structure of the phosphor though exposure and developing. The luminous efficacy of the white LEDs is finally increased (higher than 100 lm/W for one die) though optConformal-coating technology of power white LEDs uses PVA+ADC water-solution compounding yellow phosphor to coat on the surface of the die,then gets planar structure of the phosphor though exposure and developing. The luminous efficacy of the white LEDs is finally increased (higher than 100 lm/W for one die) though optimizing the technology including the stabilization of processing step and exposure time,confining the every element including comparison experiment of darkroom and the control of temperature. It is stabilized in color temperature of 5000 K and luminous efficacy of 90 lm/W..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 72301 (2010)
Physical Optics
Reviews of Recent Researches on Airy Beams
Xu Jia, Liu Juan, Xie Jinghui, and Wang Yongtian
The theory and application of nondiffraction beams is one of the most important topics in various optical fields,where the Airy beams appear as a new member of nondiffraction beams family in very recent years. The latest research on Airy beams is introduced,including the principle and three singularities:free acceleratThe theory and application of nondiffraction beams is one of the most important topics in various optical fields,where the Airy beams appear as a new member of nondiffraction beams family in very recent years. The latest research on Airy beams is introduced,including the principle and three singularities:free acceleration,nondiffraction and self-healing. The promising applications of Airy beams are summarized as well..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 70501 (2010)
Radially Polarized Laser with End-Pumped and Bonded Nd:YAG Crystal
Lin Di, Li Jianlang, and Xia Kegui
An end-pumped solid-state laser emiting radially polarized laser beam was reported. The bonded Nd:YAG crystal was applied as gain medium with the structure of YAG+Nd:YAG+YAG. The radially polarized mode was excited by employing photonic crystal grating as the polarization-selective element and the output coupler. In thAn end-pumped solid-state laser emiting radially polarized laser beam was reported. The bonded Nd:YAG crystal was applied as gain medium with the structure of YAG+Nd:YAG+YAG. The radially polarized mode was excited by employing photonic crystal grating as the polarization-selective element and the output coupler. In the condition of 2 W absorbed pumping power,the radially polarized laser output power reaches to 264 mW with a polarization purity of 96.5% and a slope efficiency of 58.1%..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 71405 (2010)
Study on Nonlinear Propagation Effects of Special Laser Beams
Qi Yihong, Niu Yueping, Cui Ni, and Gong Shangqing
The studies on coherent control of extreme nonlinear optical properties via few-cycle laser pulses in atomic and atomic-like systems are reviewed,including self-focus effects on extreme nonlinear optics,self-induced transmission,resonant multipole vector solitons,etc. Due to the transverse effect,the 2nπ sech-pulse defThe studies on coherent control of extreme nonlinear optical properties via few-cycle laser pulses in atomic and atomic-like systems are reviewed,including self-focus effects on extreme nonlinear optics,self-induced transmission,resonant multipole vector solitons,etc. Due to the transverse effect,the 2nπ sech-pulse deformes and breaks up during the propagation. With further propagation,interference of the crescent-shape pulses,constructive interference and self-focusing phenomena are observed. Conventional area theorem is invalid in the study of ultrashort pulse in quantum wells. By defining effective area,the self-induced transmission of ultrashort pulse with effective area of 2π is investigated. The formation and propagation of resonant multipole vector soliton with weak light intensity are studied in a tripod-type atomic system,in which large nonlinearity and nearly vanishing absorption are achieved due to the quantum interference effect..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 71902 (2010)
Representation Theory and Physical Properties of Finite Electromagnetic Beams
Li Chunfang, He Ying, and Yang Yanfang
Our research of the representation theory of nonparaxial light beams and their physical properties such as a global parameter of a unit vector,the orbital angular momentum,the transverse effect,and the so-called spin Hall effect of light is introduced. On the basis of the plane-wave spectrum expansion,a representation Our research of the representation theory of nonparaxial light beams and their physical properties such as a global parameter of a unit vector,the orbital angular momentum,the transverse effect,and the so-called spin Hall effect of light is introduced. On the basis of the plane-wave spectrum expansion,a representation formalism for finite beams is developed. After postulating a Jones vector that acts as a global quantity to represent the beam′s polarization,another global quantity,a unit vector is introduced. Both of the two global quantities are important in the representation formalism of finite beams. By using this formalism,the total angular momentum of an arbitrary free electromagnetic field is separated rigorously into spin and orbital parts,both of which are dependent on the state of polarization and the polarization ellipticity. In addition,the observed so-called spin Hall effect of light in both refraction and reflection is explained satisfactorily in terms of the change of the characteristic unit vector..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 72601 (2010)
Research on Electron Spin Dynamics in Semiconductor
Ma Hong, Jin Zuanming, and Ma Guohong
The electron spin dynamics of Ⅲ-Ⅴsemiconductor InP and Ⅱ-Ⅵ semiconductor CdTe are studied by using femtosecond time resolved circularly polarized pump probe spectroscopy. Experimental results show that the spin relaxation time in CdTe with a few picoseconds is faster than that in InP. With the increase of the excitatioThe electron spin dynamics of Ⅲ-Ⅴsemiconductor InP and Ⅱ-Ⅵ semiconductor CdTe are studied by using femtosecond time resolved circularly polarized pump probe spectroscopy. Experimental results show that the spin relaxation time in CdTe with a few picoseconds is faster than that in InP. With the increase of the excitation photon energy,the spin relaxation time constant decreases monotonically. However,with increasing the carrier concentration,the spin relaxation time constant first increases,reaches a maximum and then decreases. This result coincides with theoretical prediction based on the microscopic kinetic spin Bloch equations in which Coulomb interaction is considered..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 73201 (2010)
Remote Sensing and Sensors
Research on New Portable Laser Rangefinder
Wang Gang, Sun Lingyu, Wang Weining, Zhu Nan, and Feng Lichun
The structure,working theory and using method of a new laser rangefinder,are introduced. The new laser rangefinder can not only well combine the distance-measuring technology with the angle-measuring technology but also add two rotating handles with semiconducting laser device and one goniometer. The goniometer appliesThe structure,working theory and using method of a new laser rangefinder,are introduced. The new laser rangefinder can not only well combine the distance-measuring technology with the angle-measuring technology but also add two rotating handles with semiconducting laser device and one goniometer. The goniometer applies the theory of circle grid-capacitance sensor to make it easier for distance and angle-measuring and more practical in use..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 72801 (2010)
Reviews
Key Technology of Laser Welding of Galvanized Steel
Zhang Yi, Li Shichun, Jin Xiangzhong, Chen Genyu, and Mei Lifang
Galvanized steel is widely used in industry due to its excellent corrosion resistance. However,the zinc coating greatly reduces the welding process property of galvanized steel. As a new technique,laser welding is implemented to realize the joint of galvanized steel. There are two unique characteristics,zinc vaporizatiGalvanized steel is widely used in industry due to its excellent corrosion resistance. However,the zinc coating greatly reduces the welding process property of galvanized steel. As a new technique,laser welding is implemented to realize the joint of galvanized steel. There are two unique characteristics,zinc vaporization and zinc plasma,existing in deep penetration laser welding of galvanized steel. The key issue of laser welding of galvanized steel is the influence of the zinc vapor during the welding process. The reduction and elimination of the zinc coating evaporation are the fundamental methods to avoid the influence of the zinc vapor. Based on the key technology of laser welding of galvanized steel,varied welding processes and solutions are discussed to improve the quality of the laser welding,including specific processes,process parameters and simulation optimization,as well as the online monitoring and controlling during the welding process..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 71401 (2010)
Cryogenically Cooled High Average Power Yb:YAG Laser
Wu Wuming, Wu Huiyun, Xu Xiaojun, and Guo Shaofeng
Thermal effects in solid state laser media have become a bottleneck of the development towards high power for diode-pumped sold state laser. The cryogenically cooled Yb:YAG solid state laser can realize high average power and good beam quality. Its advantages including low laser threshold,high efficiency and scalable oThermal effects in solid state laser media have become a bottleneck of the development towards high power for diode-pumped sold state laser. The cryogenically cooled Yb:YAG solid state laser can realize high average power and good beam quality. Its advantages including low laser threshold,high efficiency and scalable output,are summarized. The thermo-optic and spectroscopic properties of Yb:YAG crystal at lower temperatures are analyzed,which makes it possible to provide efficient laser sources with small thermal effect. Finally three different cooling methods are compared and the progress in cryogenically cooled high average power Yb:YAG laser is presented..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 71403 (2010)
New progress on Detection of Biological Cells
Bu Min, Lei Haina, and Wang Yawei
The recent advances in cells detection technology are summarized. The latest progresses of traditional detection techniques are introduced,including image recognition and fluorescence microscopy. Then the developments of phase microscopy based on digital holography are introduced. In particular,the principles,technicalThe recent advances in cells detection technology are summarized. The latest progresses of traditional detection techniques are introduced,including image recognition and fluorescence microscopy. Then the developments of phase microscopy based on digital holography are introduced. In particular,the principles,technical characteristics and productions about Fourier phase microscopy (FPM) and Hilbert phase microscopy (HPM) are recommended. Finally,it is forecasted that the cell-phase pattern recognition based on the digital holography is the future development trends of cells detection technology..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 71701 (2010)
Optical Properties of Gold Nanorod and Its Application in Biological Imaging and Photothermal Therapy
Yang Yudong, Xu Jinghua, Yang Linmei, and Pa Weisan
Compared with spherical gold particles,rod-shaped ones exhibit more unique properties of surface plasma resonance (SPR). Gold nanorods have two SPR peaks. The lengitudinal suface plasma resonances position depends on rods′ aspect ratio. Thus,the LSPR′s position can be controlled from the visible region to the near infrCompared with spherical gold particles,rod-shaped ones exhibit more unique properties of surface plasma resonance (SPR). Gold nanorods have two SPR peaks. The lengitudinal suface plasma resonances position depends on rods′ aspect ratio. Thus,the LSPR′s position can be controlled from the visible region to the near infrared by adjusting the aspect ratio of gold nanorods. Gold nanorods have great potential use in biological tissue imaging,cancer diagnosis and therapy because of it′s SPR and strong absorption induced luminescence. Au-ligand conjugates can specifically target the receptor on cancer cells,provide specific information about specific molecules,and allow molecular-specific imaging and cancer detection. Gold nanorods can efficiently absorb optical energy into localized heat,and induce protein denaturation and cells death.The optical properties of kinds of gold nanorods are summarized,and the research progress of selective targeting of gold nanorods in biological imaging,cancer diagnoses and photothermal therapy is reviewed..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 71702 (2010)
Research Progress of Flexible Electrode for Dye-Sensitized Solar Cells
Wang Song, Yu Zhongchen, Liu Jiwei, Dai Chunlei, and Zhang Lei
Flexible electrode has broad market prospects due to its low cost,light weight,convenience to carry and prepare a large area cell. The different preparation methods of flexible electrode for dye-sensitized solar cells (DSSC) are reviewed. These methods involve hydrothermal method,microwave irradiation,UV irradiation,meFlexible electrode has broad market prospects due to its low cost,light weight,convenience to carry and prepare a large area cell. The different preparation methods of flexible electrode for dye-sensitized solar cells (DSSC) are reviewed. These methods involve hydrothermal method,microwave irradiation,UV irradiation,mechanical press,deposition,sputtering and low-temperature sintering,etc. The photoelectric performances of the DSSC assembled by different flexible electrodes are compared. The latest research progress and further development on the flexible electrode are introduced..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 73101 (2010)
Scattering
Influence of Aspect Ratio on Mueller Matrices of Hexagonal Ice Crystals in Random Orientation
Lei Chengxin
Mueller-matrix elements of hexagonal ice crystals in random orientation are calculated by the discrete dipole approximation (DDA) method and the profiles of Mueller-matrix elements are presented.The influence of the aspect ratio on Mueller matrices of hexagonal ice crystals in cirrus cloud is discussed. The results shoMueller-matrix elements of hexagonal ice crystals in random orientation are calculated by the discrete dipole approximation (DDA) method and the profiles of Mueller-matrix elements are presented.The influence of the aspect ratio on Mueller matrices of hexagonal ice crystals in cirrus cloud is discussed. The results show that the influence of the aspect ratio on Mueller matrix elements of hexagonal ice crystals in random orientation is quite large in certain angular regions,and it varies with the size parameters of the hexagonal ice crystals in random orientation. In addition,there is a nodical point in the profiles of mueller matrices of hexagonal ice crystals with the same sizes but different aspect ratios,and this point will extend forward with the increase of the size parameters of particles..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 72901 (2010)
Thin Films
Relationship between UV Emission Intensity and Detection Angle of ZnO Films
Wang Zhaoyang
There are two main principles of UV light emission of ZnO thin films fabricated by different methods:micro-resonant cavity light emission and random light emission. The variation of the intensity of light emission of ZnO thin films grown by the two methods with detection angle was studied at the same condition and the There are two main principles of UV light emission of ZnO thin films fabricated by different methods:micro-resonant cavity light emission and random light emission. The variation of the intensity of light emission of ZnO thin films grown by the two methods with detection angle was studied at the same condition and the variation tendency of the intensity was also analyzed. It is proved that they have different principles because of the different crystal structures. ZnO thin films grown by pulsed laser deposition have hexangular column honey comb like structure and its column borders play the role of light amplification reflecting mirror and form micro-resonant cavity. So the lateral surface has the strongest light emission. ZnO thin films grown by thermal oxidation have granular nanomicro-crystal structure and photons are scattered through grains. Light amplified emission occurs from the randomly scattered closed paths. So its intensity of light emission varies with the detection angle slowly..
Laser & Optoelectronics Progress
- Publication Date: Jun. 03, 2020
- Vol. 47, Issue 7, 73102 (2010)
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