通过模拟和地面多光谱测量实现大气透过率监测

1.引言空气污染的日趋严重以及它对地域性和全球性气候、环境资源的影响,要求能够准确地估计城市大气的真实辐射特性。了解大气光谱透过率对于估计污染大气对天气和气候变化的影响,以及研究空气污染与能量交换.尤其是可见光谱范围内污染区域的卫星数据校正十分重要。在工业污染区,NO_x的增加导致了臭氧的降低;此外,SO_2大量的被排放到大气中,而后     

衰荡腔腔长失调的实验分析

光腔衰荡法是一种高反射率的测量技术.在腔长失调的情况下,根据高斯光束空间传输表达式和光腔衰荡法测量原理,建立了反射率测量的理论模型.利用模拟计算,得到了腔长失调对衰荡信号的影响.通过与实验现象相比较,证明了理论分析方法是合理的.     

多面体扫描电弧成象仪

交流喷口电弧瞬态温度实时测量是目前高压电器领域里的一个难题。要深入研究高压输电线路中的气吹断路器灭弧机理,必然要涉及到在极短时间内测量电弧等离子体温度变化问题。电弧等离子体是一种高温电离气体,它辐射出丰富的光谱信息。采用光谱法测量是合适的。转镜式电弧成象仪正是为实现上述测量而研制的专用设备。它与光栅光谱仪、高速数据采集系统、微机等构成一套完整的电弧光谱温度测量系统。本文论述了该设备的总体方案、设计特色、整机性能指标。     

Inverse determinations of the parameters of three-layered plate using angle probe generated Lamb waves

The study on the inverse problems in the ultrasonic nondestructive testing (NDT) has a wide application field in various industries. An error function based inversion algorithm is introduced to determine the parameters of three-layered plates from the measured velocity of multi-mode Lamb waves. A mixed-spectral estimation is proposed to combine FFT with AR model for exact determination of the ultrasonic phase velocity. Experiments are performed using two conventional angle probes as transmitter and receiver on the same surface of three-layered laminates. Inverse analyses of one parameter (thickness) and two parameters (longitudinal and transverse wave velocities in a layer, or thickness of two layers) of three-layered laminates are made. The experimental results show that the inverse approach is in good agreement with the actual value.     

Spectroscopic properties of Tm,Ho:LiLuF_4

LiLuF4 single crystals co-doped with thulium （5%） and holmium （0.5%）, having large size, intact shape, and high optical quality, are successfully grown by the Czochralski technique. Absorption and fluorescence spectra of the crystal are measured. The absorption spectrum shows that the main absorption band locates at near 686 and 792 nm and the fluorescence spectrum peaks at 2.05 um. At room temperature, the as-grown Tin, Ho： LiLuF4 single crystals are end-pumped by a fiber-coupled laser diode system with pumping wavelength of 795 nm under CW operations. A power of 50 mw contin- uous laser outout at 2.05-um wavelength is achieved. Meanwhile an obvious green light is detected.     

Ultrafast spectroscopy of semiconductor saturable absorber mirror

Ultrafast spectroscopy of semiconductor saturable absorber mirror(SESAM) is measured using a femtosecond pump-probe experiment.This allows dynamic responses of SESAM in the cavity to be concluded by ultrafast spectroscopy.Change in reflection is measured as a function of pump-probe delay for different pump excitation fluences.Change of nonlinear reflection of SESAM is measured as a function of incident light energy density.When the excitation fluence increases,nonlinear change in ultrafast spectroscopy of SESAM becomes increasingly significant.When SESAM is pumped by an ultrahigh excitation fluence,the energy density of which is approximately 1400 μJ/cm2,two-photon absorption can be observed visibly in its ultrafast spectroscopy.     

《光谱学与光谱分析》2014年征订启事

《光谱学与光谱分析》1981年创刊,国内统一刊号:CN 11-2200/O4,国际标准刊号:ISSN 1000-0593,CODEN码:GYGFED,国内外公开发行,大16开本,292页,月刊;是中国光学学会主办,钢铁研究总院、中国科学院物理研究所、北京大学、清华大学共同承办的学术性刊物。北京大学出版社出版,每期售价45元,全年540元。刊登主要内容:激光光谱测量、红外、拉曼、紫外、可见光谱、发射光谱、吸收光谱、X射     

掺Ce~(3 )的BaClF:Sm~(2 )微晶制备及其光谱

首次制备出粉末微晶BaClF :Sm2 发光材料。发现在该微晶材料中掺入少量CeCl3 杂质 ,可以极大地催化Sm3 →Sm2 的还原过程 ,极大地提高Sm2 的发光亮度 ,制备出较好的BaClF :Sm2 ,Ce3 微晶发光材料。     

Characterization of tissue cells by full information from spectral interferogram

A new method for characterizing living tissue cells is demonstrated using both phase and amplitude information derived from the spectrally resolved interferogram in a single measurement.The effect of the light source spectral distribution can be cancelled out with the help of the zero order spectrum of the Fourier transform of the interferogram.The ratio of amplitudes between the two interference beams is acquired without this effect.The group delay,the first and second order dispersions,and the absorption,etc.,for the full wavelength range can be measured.The results of the culture medium and the HeLa living cells are given.In addition,the measured values of d2 n/dλ2 and absorption of the distilled water are also provided for comparison.     

小孔径蝴蝶型光电导天线太赫兹辐射源的研究

研究了5种小孔径光电导天线的太赫兹发射特性,并且对它们所发射的太赫兹波进行了对比,为研制高效率的太赫兹波发射源提供了参考依据。利用太赫兹时域光谱技术测量了光电导天线发射的太赫兹（THz）脉冲,得到了时域发射光谱,并通过快速傅里叶变换得到相应的频域光谱。结果表明,太赫兹信号强度随偏置电压的增大而增强;随着泵浦激光功率的增大而增强并出现饱和现象。偏置电压与泵浦激光功率相同时,我们对比5种光电导天线产生的太赫兹信号,从中找到了一种发射效率较高的小孔径光电导天线,并且研究了电极形状、电极间距对光电导天线发射效率的