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Effect of the reflection of underlying surface on sky radiance distribution

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Chinese Optics Letters 2007年第3期5卷 125-127页

作者：杨春平魏凌吴健冷杰 School of Opto-Electronic Information University of Electronic Science and Technology of China Institute of Applied Electronics China Academy of Engineering Physics

Sky radiance might be influenced by the multiple reflectance between the earth＇s albedo surface and the atmosphere. Based on the Lambert＇s law and the radiative transfer equation （RTE）, a model is developed to calculate the additional sky radiance at wavelengths of 0.4-3μm due to the reflectance contribution of the underlying surface. The iterative method is used to calculate sky radiance without the reflectance from underlying surface. The hybrid modified delta-Eddington approximation is used to compute the atmospheric reflection of the radiation from the earth＇s surface. An interaction factor is introduced to deal with the multiple reflectance between the atmosphere and the underlying surface. The sky radiance increment is evaluated for some different albedos of the earth＇s surface. The results show that the sky radiance increment rises rapidly while viewing zenith angle is near to 90°and the larger the albedo of the earth＇s surface is, the more obvious this effect appears.

关键词： Atmospheric optics Iterative methods light reflection Mathematical models

Wide-band double-pass discrete Raman amplifier with reflection of signals and pumps

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Chinese Optics Letters 2004年第8期2卷 480-482页

作者：王元崔一平 Department of Electronic Engineering Southeast University Nanjing 210096 Department of Electronic Engineering Southeast University Nanjing 210096 wide-band (1530-1610 nm) and high efficient double-pass discrete Raman amplifier is reported. In this Raman amplifier by using a one-end gilded fiber as the broadband reflector signals and multi-pump are both reflected to propagate through the gain fiber for a second time. An increase in net gain of more than 150% has been achieved compared with that in the typical co-pumped Raman amplifier. The advantages of this proposed new configuration have been experimentally studied by comparing with the recently existing Raman amplifier configurations.

A wide-band (1530-1610 nm) and high efficient double-pass discrete Raman amplifier is reported. In this Raman amplifier, by using a one-end gilded fiber as the broadband reflector, signals and multi-pump are both reflected to propagate through the gain fiber for a second time. An increase in net gain of more than 150% has been achieved compared with that in the typical co-pumped Raman amplifier. The advantages of this proposed new configuration have been experimentally studied by comparing with the recently existing Raman amplifier configurations.

关键词： light reflection Optically pumped lasers Raman scattering

Negative refraction and reflection of Gaussian beam on two-dimensional photonic crystal slab

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Chinese Optics Letters 2006年第4期4卷 230-233页

作者：方云团刘玉真沈廷根 Department of Physics Zhenjiang Watercraft College Zhenjiang 212003 Department of Physics Nanjing University of Science and Technology Nanjing 210094 Department of Physics Jiangsu University Zhenjiang 212003

The refraction and reflection of Gaussian beam on two-dimensional photonic crystal （2DPC） slab are studied by the finite-difference time-domain （FDTD） method. It is shown that 2DPC slab enables negative refraction, which is demystified by the distribution of Poynting vector directions and values inside the 2DPC. A negative Goos-Haenchen shift is also found in the simulation.

关键词： Computer simulation Electromagnetic fields Finite difference method light reflection light refraction Maxwell equations Time domain analysis

Determination of human skin optical properties in vivo from reflectance spectroscopic measurements

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Chinese Optics Letters 2007年第3期5卷 181-183页

作者：杨洪钦谢树森李晖陆祖康 Key Laboratory of Optoelectronic Science and Technology for Medicine (Fujian Normal University) Ministry of Education and Institute of Laser & Optoelectronics TechnologyFujian Normal University State Key Laboratory of Modern Optical Instrumentation Zhejiang University

A novel approach has been proved to quickly and non-invasively determine the optical properties of human skin in vivo. It is based on the diffuse reflectance approximation model and subjected to the well established library of absorption spectra of water and hemoglobin. Under the nonlinear least-square algorithm, fitting the measured spectra in the range of 400--1000 nm to the diffusion approximation model, the reduced scattering coefficient and absorption coefficient of skin tissue can be quickly determined in vivo. The results show that this method is convenient and suitable for the real-time clinical application.

关键词： Absorption spectra Least squares approximations light reflection Optical properties

Nonpolarizing guide-mode resonance filter with ultra-narrow linewidth

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Chinese Optics Letters 2011年第3期9卷 88-90页

作者：张帆袁博许丽丽 Institute of lightwave Technology Beijing Jiaotong University

Ultra-narrow linewidth,nonpolarizing guide-mode resonance （GMR） filters with single and double common resonance wavelengths are designed.The guide-mode resonance filters consist of a single grating layer with asymmetric profiles.By choosing appropriate parameters,same resonance wavelengths for both transverse electric （TE） and transverse magnetic （TM） polarizations can be achieved.Results show that high reflection （more than 99.9%） is obtained at every resonance wavelength,and the full-width at halfmaximums （FWHMs） of TEand TM-polarized light are only 0.008 and 0.215 nm,respectively.

关键词： light reflection

Influence of purity of HfO_2 on reflectance of ultraviolet multilayer

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Chinese Optics Letters 2008年第3期6卷 222-224页

作者：袁景梅齐红基赵元安范正修邵建达 R and D Center for Optical Thin Film Coatings Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences

The impurities in two kinds of HfO2 materials and in their corresponding single layer thin films were determined through glow discharge mass spectrum technology and secondary ion mass spectrometry （SIMS） equipment respectively. It was found that ZrO2 was the main impurity in the two kinds of HfO2 either in the original HfO2 materials or in the electron beam deposited films. In addition, the difference of Zr content in the two kinds of HfO2 single layer films was much larger than that of the other impurities such as Ti and Fe, which showed that it was just ZrO2 that made the difference between the optical performance of the film products including the two kinds of HfO2. With these two kinds of HfO2 and the same kind of SiO2, we deposited HfO2/SiO2 multilayer reflective coatings at the wavelength of 266 nm. Experimental results showed that the reflectances of these two mirrors were about 99.85% and 99.15% respectively, which agreed well with the designed results what were based on the optical constants obtained from the corresponding single layer thin films.

关键词： Glow discharges Hafnium compounds light reflection Multilayer films Optical constants Optical properties Reflective coatings Secondary ion mass spectrometry Thin films

Improvement on peak-to-trough ratio of sampled fiber Bragg gratings with multiple phase shifts

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Chinese Optics Letters 2008年第1期6卷 9-11页

作者：谢滨潘炜罗斌邹喜华 School of Information Science and Technology.Southwest Jiaotong University

Via a cascaded structure, the peak-to-trough ratio is considerably improved for sampled fiber Bragg gratings （SFBGs） based on multiple-phase-shift （MPS） technique. This cascaded filter is composed of two identical SFBGs which are inserted with the increasing or decreasing arrangement of phase shifts. With this inverse arrangement of MPS in grating design, the phase fluctuation of individual SFBG can be compensated, and as a result an excellent phase matching condition is realized. In this way, the peak-to- trough ratio in reflection spectra is improved from 6 to 12 dB when multiplication factor m = 4, and from 5dBto 10dBwhenm=8.

关键词： light reflection Phase matching Phase shift

Optimized design and experiment of one-dimensional omnidirectional reflector using P-wave angle domain compensated overlapping method

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Chinese Optics Letters 2007年第11期5卷 665-667页

作者：李夏薛唯蒋玉蓉王华清喻志农 Department of Photoelectronics Engineering School of Information Science and Technology Beijing Institute of TechnologyBeijing 100081

The optimized method of extending the omni-photonic band gap （omni-PBG） was discussed based on analyzing the P-wave reflectivity characteristics in one-dimensional （1D） periodic multilayer film. A visible omnidirectional reflector with hybrid structure was designed using P-wave compensated overlapping in angle domain. The experimental result was in good agreement with the theoretical simulation.

关键词： light reflection Multilayer films One dimensional Optimization Photonic band gap

Calculation on diffraction aperture of cube corner retroreflector

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Chinese Optics Letters 2008年第11期6卷 833-836页

作者：李松唐蓓周辉 School of Electronic Information.Wuhan University Wuhan 430079

On the basis of optical property of cube corner retroreflector （CCR）, a new perception and calculation approach for diffraction aperture of CCR in two different forms is presented. The relationship between diffraction apertures and incident light with six different combinations of reflection order and incident angle is established. Far-field diffraction patterns of CCR under various incident conditions are also provided.

关键词： Diffraction Holograms Holographic interferometry light reflection Optical properties