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题名	高功率超短激光脉冲光谱整形技术
作者	郭爱林
学位类别	博士
答辩日期	2009
授予单位	中国科学院上海光学精密机械研究所
导师	朱健强 ; 谢兴龙
关键词	高功率超短激光 增益窄化 光谱红移 窄带 光谱整形
其他题名	Spectral shaping of high-power ultrashort laser pulse
中文摘要	获取更高峰值功率的激光脉冲是激光技术发展的主要方向之一。由于激光系统的规模与投资成本主要决定于激光脉冲的能量，因此，与增加激光脉冲的能量相比，通过压缩脉宽来提高激光脉冲的峰值功率是更加经济可行的方案。利用啁啾脉冲放大技术可以获得峰值功率高达PW量级的高功率超短激光脉冲。 通过分析啁啾脉冲在线性介质中的传输特性和放大方程组得知，当压缩器完全补偿放大啁啾脉冲的色散时，影响压缩脉冲的脉宽和信噪比的主要因素是光谱窄化和偏移造成的光谱振幅调制以及放大过程中的非线性B积分，在相同的峰值B积分下平滑光谱的脉冲具有更高的信噪比。 在谱域对啁啾脉冲放大方程进行逆运算得知，输入脉冲的谱宽较输出脉冲的宽，且光谱具有中间凹陷的非对称分布可以补偿放大过程中的光谱窄化和偏移的影响。由于钕玻璃激光系统的光谱比较窄，将已有的光谱整形技术应用到窄带激光时存在调制的效果不稳定或者色散调制的问题。二元光学面板或者液晶空间光调制器的像素化、阶跃式的调制增强了B积分的负面影响，此外，液晶空间光调制器还存在空间相位畸变的问题。因此，为实现窄带激光脉冲的光谱整形，其关键在于寻求平滑的空间纯光强调制技术。 根据啁啾脉冲放大系统的特点，本文创新性地提出了两种可用于钕玻璃窄带高功率激光放大系统的光谱调制技术：变栅距反射光栅实现窄带激光脉冲的光谱整形技术和石英晶体平凸透镜光谱整形技术。 本论文的工作为高功率钕玻璃窄带啁啾脉冲放大器提供了克服增益窄化效应的光谱整形技术，对获得脉宽更短、峰值功率更高的大能量激光脉冲具有重要的意义。
英文摘要	The pursuit of laser pulses with higher-peak-power is one of the main purposes of laser technology. Since the size and investment of the laser system are mainly determined by the output energy, compared with increasing the pulse energy, shortening the pulse duration is a more robust solution to increase the peak power. With the aid of the technology of chirped pulse amplification, ultrashort laser has attained a peak power up to around peta-watt. For an understanding of chirped pulse amplification, it is necessary to analysis the basic equation that governs propagation of chirped pulse in dispersive linear media and the amplification equation for ultrabroad bandwidth chirped pulse. The results indicate that the duration and signal-to-noise ratio of the compressed pulse are mainly affected by B-integral and spectrum-amplitude modulation, supposed that the frequency chirp of the amplified chirped pulse is fully compensated by the grating compressor, the pulse with smooth spectrum has a higher signal-to-noise ratio under the same peak B-integral. The inverse operation of the chirped pulse amplification in frequency domain indicates that the seed pulse with broader bandwidth and asymmetric saddle-shape spectrum can compensate for the spectral distortion in the amplifier. Owing to the relatively narrow spectrum of the neodymium-glass laser system, there are significant problems in instability and dispersion modulation, the pixel structure of liquid crystal spatial light modulator and binary mask with step-like modulation will enhance the negative effects of B-integral. In addition, there is a problem of phase distortion in the case of liquid crystal spatial light modulator. Therefore, in order to compensate for the gain narrowing effect in the narrow-band chirped pulse amplification, it is crucial to seek a spatial modulation strategy provides smooth amplitude-only modulation. In order to take full advantage of amplifier gain-bandwidth and obtain a shorter pulse with higher power in the terminal, based on the characteristics of chirped pulse amplification system, two efficient innovations have been proposed in this paper which can be used for spectral shaping in narrow-band and high-power neodymium glass laser pulse amplification systems: Spatial grating with variable line-space and quartz crystal plano-convex lens in combination with a polarizer. The mainly achievements of the thesis is the solutions for narrow-band spectrum shaping to compensate for the gain narrowing which occurred in high-energy and high-power neodymium-glass laser pulse systems, and it is very significant for ultrashort and high-energy laser systems to increase the peak-power by shortening the pulse duration.
语种	中文
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/15275]
专题	上海光学精密机械研究所_学位论文
推荐引用方式 GB/T 7714	郭爱林. 高功率超短激光脉冲光谱整形技术[D]. 中国科学院上海光学精密机械研究所. 2009.

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