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题名	飞秒强场中Ne和Ar原子的高次谐波辐射及其空间与光谱特性的实验研究
作者	谢新华
学位类别	硕士
答辩日期	2004
授予单位	中国科学院上海光学精密机械研究所
导师	李儒新
关键词	飞秒激光 高次谐波 相位匹配 频谱特性
其他题名	Experimental study on spatial and spectral characteristics of high-order armonics from Ne and Ar atoms driven by an intense femtosecond laser field
中文摘要	当线偏振的超强超短激光脉冲和原子，原子团簇或分子相互作用时，会产生在极紫外和软X射线波长范围的高次谐波辐射（High-ordcr harmollic generation，HHG）。因其易于在小型的实验台上产生、脉冲宽度极短、相干性及方向性极好，通过高次谐波过程产生相千X射线光源极具发展前景。随着阿秒（10-18秒）脉冲的在高次谐波中的诞生，人类通过实验研究原子内壳层电子的超快动力学成为现实，推动超快科学实现从飞秒化学到阿秒物理的飞跃。高次谐波作为一种新的科学实验手段，越来越受世人的瞩目。目前，虽然高次谐波已经在阿秒的产生和应用，等离子体光谱学及X射线荧光分析等领域中得到应用。本文对高重复率低能量飞秒脉冲激光和惰性气体原子相互作用产生高次谐波进行了实验研究：1，建立了一套小型化的气体高次谐波产生和光谱测量实验装置，该装置可以用于进行激光和各种气体物质相互作用的研究。并且利用Ne气体的47次谐波和铝的吸收边完成了X射线谱仪的定标。2，实验研究了飞秒激光脉冲和静态Ne相互作用产生的高次谐波，获得了33次至47次谐波的输出，研究了高次谐波产生与Ne气体压强的关系，并初步分析了其高次谐波的频谱特性一蓝移和展宽。3．实验研究了飞秒激光脉冲和静态Ar作用产生的相位匹配高次谐波，获得了21次至33次的谐波输出，其中相位匹配27次谐波获得，1×10-7的转化效率，同时研究了谐波的频谱特性。此外，首次发现了相位匹配条件下高次谐波的强度分布和非相位匹配情况截然不同，分析了平顶型高次谐波输出产生的原因。4．初步实验研究了不同直径小孔对抢高次谐波产生的影响，并且发现了高次谐波谱的分裂现象。
英文摘要	High-order harmonics are generated by coherent interaction of an intense laser and atoms, clusters or molecules. Because of its excellent spatial and temporal coherence, low divergence and being obtained from a tabletop experimental system, high-order harmonics has become a desirable coherent short wavelength source. With the development of the intense ultrashort pulse laser, the research of high-order harmonic generation has reached the water-window in spectral region and attosecond in time domain. Especially, the generation and application of attosecond pulse led the study of high-order harmonic generation into a completely new world. It has made the study of ultrafast science from the femtochemistry to the attophysics. In this thesis, we experimentally investigated high-order harmonic generation from the interaction of femtosecond laser pulses with atoms. The main results are shown as follows: 1. We developed a compact high-order harmonic generation and detection setup for the interaction of femtosecond laser pulses with atoms. Soft X-ray spectrometer was calibrated by the 47th harmonic of Neon gas and the absorption edge of Aluminum. 2. High-order harmonic generation from static neon gas was studied experimentally. Harmonics from 33 rd to 47th were obtained in the experiment from different neon gas density. Moreover, spectral blueshift and broadening of high-order harmonic generation were explored. 3. We also investigated phase-matched high-order harmonic generation by the interaction of argon atoms with high-repetition-rate low-energy femtosecond laser pulses. Harmonics from 21st to 33rd were obtained experimentally and phase-matched 27th harmonic was acquired with the conversion efficiency 1×10~7. High-order harmonic generation in different gas density was studied systematically. Spectral blueshift and broadening of high harmonics in different pressure were analyzed. For the first time, we found that the spatial distribution profile of high-order harmonics is flat-top under the phase-matching condition, which is quite different from that of the phase-mismatching case. 4. Furthermore, we had a preliminary study on the influence of different diameter aperture on high-order harmonic generation, and we found that the spectrum of each harmonic was split into two peaks.
语种	中文
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/16515]
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	谢新华. 飞秒强场中Ne和Ar原子的高次谐波辐射及其空间与光谱特性的实验研究[D]. 中国科学院上海光学精密机械研究所. 2004.

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