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981.
光子晶体光纤及其应用 总被引:3,自引:1,他引:2
光子晶体作为一种新兴的材料 ,将会对整个光子学和光子产业领域产生深远的影响 ,而其最重要的应用之一———光子晶体光纤已经在很多科研技术领域得到了应用 .文章综述了光子晶体光纤的研究进展 ,给出其分类 ,并重点介绍了光子晶体光纤在超短脉冲、光频测量、光纤通信等科研领域的重要应用以及未来的发展前景 相似文献
982.
V.P. Nayyar 《Optical and Quantum Electronics》2002,34(7):697-705
Using statistical approach the author has solved the equations for the mutual coherence function of partially coherent Gaussian laser beams in graded-index fibres. The expressions for the complex degree of coherence and the intensity distribution have also been shown that the self-focusing length inside the fibre depends upon the degree of coherence. The result have been discussed for both conical and cylindrical guides. 相似文献
983.
J. Schneider D. Hauschild Ch. Frerichs L. Wetenkamp 《International Journal of Infrared and Millimeter Waves》1994,15(11):1907-1922
We report highly efficient CW fiber lasers at 2.7µm in an Er3+-doped and weakly Pr3+-codoped fluorozirconate fiber. The fiber lasers were pumped in three pump wavelength ranges around 650, 795 and 980 nm. Higher output powers of nearly 30 mW and a broader potential tuning range of 180 nm compared to Er3+ singly doped fiber lasers are demonstrated. Laser efficiencies of more than 13% were achieved. It is shown that the fiber laser can be tuned to longer wavelengths by increasing the pump power or, in certain cases, by increasing the pump wavelength. Furthermore, we present the wavelength tuning of the Er3+:Pr3+-codoped system by an external grating. The relationships between laser wavelength and pump rates are described, and the reasons for the improvements with Pr3+-codoping are given. 相似文献
984.
LI Zhaohui 《Chinese Journal of Lasers》2002,11(5):321-323324
A novel Yb3+-doped fiber ring cavity laser pumped by a 977 nm laser diode is presented with its output laser wavelength of 1060 nm. Based on a fiber Bragg grating (FBG), the laser exhibits 0.20 nm line-width, 7.5 mW laser output power, 40 dB signal-to-noise ratio (SNR) and 66% slope efficiency.This paper proposed a ray-tracing model for the Martinez stretcher, derived the calculation formulae for the stretcher of a grating-spherical mirror system and discussed the error for the total dispersion resulted from the spatial dispersion. The calculated results show that the error could be ignored for the beam returned to the stretcher for the second pass in the wavelength range of 750 nm and 850 nm. 相似文献
985.
Ch. Frerichs 《International Journal of Infrared and Millimeter Waves》1994,15(4):635-649
Efficient operation of a cw fluorozirconate fiber laser at 2.7µm pumped at 980 nm is reported. Threshold powers below 1 mW, efficiencies up to 9.3% and output powers up to 6 mW were observed. CW laser operation occurred although the lifetime of the upper laser level is shorter than that of the lower laser level and excited state absorption from the upper laser level additionally weakens population inversion. The mechanisms clarifying cw operation of this self-terminating transition are discussed. The laser operates at several lines between 2.70 and 2.82µm, whereby the operating wavelength increases with increasing pump power. 相似文献
986.
987.
988.
989.
水样中铜,铅,镉的巯基棉富集火焰原子吸收测定 总被引:4,自引:0,他引:4
翟贵仙 《光谱学与光谱分析》1992,12(1):119-122
在测定水样中铜、铅及镉的时候用巯基棉在采样现场富集简便快速,且灵敏准确,避免了样品运送的不便和萃取富集的繁琐。 相似文献
990.
Microporous polyethylene hollow fiber membranes (EHF-1 and EHF-2) were subjected to solvent treatment, and the effects of this treatment on membrane morphology and permeating properties were studied. Membranes treated with various organic solvents exhibited enhanced permeability, enlarged pore size, and increased shrinkage in the longitudinal direction. These phenomena were found to depend on the surface tension of the solvent: the higher the surface tension of the solvent, the larger the change in morphology and permeation of the membrane. A mechanism to account for the effects of solvent treatment on the morphology of the membrane is proposed taking into consideration the influence of the type of solvent used for treatment. The enhanced morphological and permeation changes are ascribed to the formation of liquid bridges between two microfibrils of the membrane during drying followed by the deformation and adhesion of the adjacent microfibrils based on the surface tension of the solvent. 相似文献