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131.
132.
The solar cell efficiency can be improved by antireflection gratings. In this paper, the antireflection gratings with different symmetrical surface profiles are investigated by numerical simulations based on the Rigorous Coupled-Wave Analysis. Simulated results show that the antireflection performance of sharp profile such as quadratic profile has a significant improvement compared with triangular and parabolic profiles, while the top cutoff in the grating tip will severely influence the antireflection performance. Meanwhile, proper length of flat region between grating features in the nonclose-packed triangular antireflection grating can have better antireflection performance than the close-packed counterpart for the same grating period and height. Such antireflection gratings with different surface profiles may offer attractive solutions to current commercial silicon solar cell, as well as organic and other semiconductor material based solar cells. 相似文献
133.
134.
Huang Lingxiong Zhang Ge Huang Chenghui Wei Yong Zhu Haiyong 《Journal of Russian Laser Research》2008,29(6):593-598
We develop a separate 1319 and 1338 nm Nd:YAG laser system with a blazing grating (600 lines/mm). The resonator of this system
has a Littrow grating configuration and a highly reflective mirror, in which the zero-order diffraction of the grating acts
as the laser output. By virtue of the wavelength-dependent reflectivity of the grating, a single-wavelength laser at 1319
nm or 1338 nm can be realized. In view of the laser rate equations and using the distribution of the blazing grating, we analyze
the oscillation conditions providing single-wavelength laser operation in the system. 相似文献
135.
Janusz Adamus 《Proceedings of the American Mathematical Society》2002,130(11):3165-3170
Kwiecinski has proved a geometric criterion for flatness: A morphism of germs of analytic spaces is not flat if and only if its fibre power has a vertical component, for some . We show how to bound using Hironaka's local flattener: If is not flat, then has a vertical component, where is the minimal number of generators of the ideal in of the flattener of .
136.
A 1.55-m fiber grating laser (FGL) was fabricated by optically packaging a non-anti-reflection (AR) coated Fabry–Perot (FP) laser to a lensed fiber grating. The FGL demonstrates a single-longitudinal mode operation with a side-mode suppression ratio (SMSR) of up to 40 dB. The SMSR oscillates and diminishes to <30 dB as the increase of injection current above 38 mA, and the tilt of the fiber approaches 5° away from the facet normal of the FP laser. We have performed numerical simulations on the single-longitudinal mode operation for the FGL. The SMSR for the FGL increases over 40 dB as the increase of the fiber grating reflectivity (R
g) above 0.7 with non-AR-coated FP laser facet. Our calculations also show that the strong current-dependent SMSR oscillation is from the mode selection by the fiber grating external cavity and the heating effect in the FP laser. 相似文献
137.
Marek Wichtowski Andrzej Ziółkowski Ewa Weinert-Rączka 《Central European Journal of Physics》2008,6(3):546-554
In our work we propose a novel method of analysis of photorefractive transport equations. The method based on a perturbative
approach can be used in the case of two wave mixing and four wave mixing geometry, i.e. for the samples illuminated by interference
patterns. Presented approach can be employed for a broad range of material and experimental parameters, particularly for arbitrary
depth of light modulation pattern. The approximate analytical solution is compared with results of numerical calculations
and a good agreement practically in every case was found.
Presented at 9-th International Workshop on Nonlinear Optics Applications, NOA 2007, May 17–20, 2007, Šwinoujście, Poland 相似文献
138.
曝光系统离焦对平面全息光栅衍射波前的影响 总被引:1,自引:0,他引:1
波前像差是衍射光栅的重要技术指标,它直接影响光栅的分辨率。由光致刻蚀剂记录两束相干光干涉条纹是制作全息光栅的关键步骤。为了提高全息光栅曝光系统调整精度、减小离焦、降低光栅的衍射波前像差,从离焦对反射球面准直镜的准直光平行度的影响程度出发,分析了准直光平行度对全息光栅衍射波前像差的影响。理论分析和数值模拟结果表明,准直镜调整误差直接决定全息光栅衍射波前像差大小。以3种不同刻线密度光栅为例,得出了准直镜调整误差的允许变化范围。 相似文献
139.
140.
一种多波长窄线宽环形掺铒光纤激光器 总被引:2,自引:0,他引:2
本文提出了一种利用多个光纤光栅串接来实现环形掺铒光纤多波长,窄线宽激光器的新颖方法,并在实验中验证了这一设计的合理性,得到了稳定的双波长输出。 相似文献