1 中国科学院上海光学精密机械研究所强场激光物理国家重点实验室, 上海 201800
2 中国科学院大学材料与光电研究中心, 北京 100049
3 中国科学院大学, 北京 100049
飞秒强激光与气体相互作用产生高次谐波是重要的超快相干光源,模拟发现,中红外飞秒激光脉冲可以通过交流斯塔克效应在原子基态与激发态之间实现多光子共振增强,产生高亮度的单色高次谐波辐射。通过数值求解含时薛定谔方程发现,存在阈值以下共振增强的非常规高次谐波,且在较低光强下存在一个最优光强使其可以达到最高产生效率。时间-频率分析结果表明,该共振增强可通过强场下的二阶交流斯塔克效应实现,其对驱动激光波长不敏感。这种新机制使得中红外波段的飞秒激光脉冲更有利于产生高亮度的超快单色紫外/极紫外(UV/XUV)光源,在凝聚态物理、材料科学等领域具有重要的应用前景。
激光光学 斯塔克效应 单色极紫外光源 飞秒激光 高次谐波 中国激光
2019, 46(10): 1001003
Author Affiliations
Abstract
1 Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
2 Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
3 University of Chinese Academy of Sciences, Beijing 100049, China
We theoretically investigate the delay-dependent attosecond transient absorption spectra in the helium atom dressed by an infrared laser pulse in the wavelength range of 800–2400 nm. By numerically solving the three-dimensional time-dependent Schr dinger equation, we find that the absorption spectrogram exhibits a multiple-fringe structure for using the mid-infrared dressing pulse. The quantitative calculation of the transition matrix between different Floquet states provides direct evidence on the origin of the multiple-fringe structure. Our result shows that the wavelength of the dressing pulse is an important parameter and the unique feature of attosecond transient absorption spectroscopy can be induced in the mid-infrared regime.
260.3090 Infrared, far 300.1030 Absorption 340.7480 X-rays, soft x-rays, extreme ultraviolet (EUV) Chinese Optics Letters
2019, 17(8): 082601
