太赫兹场调制准相位匹配高次谐波产生  

Terahertz Field Modulated Quasi-Phase-Matched High-Order Harmonic Generation

作　　者：张轶 曾志男[1] Zhang Yi;Zeng Zhinan(State Key Laboratory of High Field Laser Physics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China;Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[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

出　　处：《中国激光》2020年第6期314-320,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金(61690223,61521093,11127901,11574332,11774363);中国科学院战略性先导科技专项(B类)(XDB16)。

摘　　要：在高次谐波产生过程中,相位匹配是提高其产生效率的必备技术。传统相位匹配技术在各向同性的气体介质中无法实现,而准相位匹配技术作为一种可行的替代方案,可以突破高次谐波产生过程中相干长度的限制,实现谐波强度随传播距离持续增加。采用准连续的逆向传播太赫兹光场调制高次谐波的产生过程,以实现准相位匹配;通过模拟计算探讨了谐波光谱与调制场参数之间的关系,结果发现获得准相位匹配的光子能量与太赫兹调制场波长成反比,与调制场场强、泵浦激光场强的比值成正比。Phase-matching is necessary to improve the efficiency of high-order harmonic generation.However,traditional phase-matching cannot be achieved in isotropic gas medium.As a feasible alternative,quasi-phase-matching breaks through the limitation of coherent length,which enables the harmonic intensity to continuously increase with the propagation distance.In this study,a quasi-CW counterpropagating terahertz field is used to modulate the generation of high-order harmonics to achieve quasi-phase-matching.The relationship between the harmonic spectra and the parameters of the modulation field is discussed through simulation.Results show that the quasi-phase-matched photon energy is inversely proportional to the wavelength of the terahertz modulation field and is directly proportional to the ratio of the field strength of the modulation to the pump field.

关 键 词：非线性光学 高次谐波 准相位匹配 太赫兹 超快光学 

分 类 号：O437.1[机械工程—光学工程]