双色激光场作用下水的高次谐波光谱移动  

High-Harmonic Spectral Shift of Water Under Two-Color Laser Fields

作　　者：赵旭琳 白丽华[1] 白亚[2,3] 刘鹏 Zhao Xulin;Bai Lihua;Bai Ya;Liu Peng(Department of Physics,Shanghai University,Shanghai 200444,China;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]上海大学物理系,上海200444 [2]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 [3]中国科学院大学材料科学与光电工程中心,北京100049

出　　处：《光学学报》2023年第13期261-267,共7页Acta Optica Sinica

基　　金：国家自然科学基金(11874373,12174412);中国科学院科研仪器设备研制项目(YJKYYQ20180023)。

摘　　要：通过求解长度规范下的半导体布洛赫方程,分析了液态水在双色场驱动下发射高次谐波光谱的特征。研究表明,通过调节双色场中基频和倍频脉冲的相对相位,高次谐波光谱呈现出周期性调制的特征。在一个调制周期内,奇次谐波会随着相对相位的增加发生红移,而产率先增大后减小。时域分析结果表明,光谱移动源于正负半周期之间发射高次谐波频谱的干涉效应。Objective High harmonic is a crucial technology for generating bright and coherent light sources in extreme ultraviolet(EUV)and X-rays for a wide range of applications,including material science,chemistry,and biology.High harmonic is also used in attosecond science,which studies the ultrafast dynamics of electrons in atoms and molecules on their natural timescale of attoseconds(10-18 s).High harmonic has traditionally been studied in gases and solids,but recent research has shown that it can also be observed in liquids.High harmonic in liquids offers several advantages over traditional gas-phase and solid-phase high harmonic.Firstly,liquids have higher electron densities than gases.Second,liquids can withstand higher laser intensities and can repair damage automatically compare with solids.Thus,high harmonic in liquids is a promising candidate for a compact and brighter EUV source.Therefore,it is crucial to reveal the underlying mechanism of liquid-phase high harmonic.However,there are many fundamental questions in liquid-phase high harmonic.In theory,Zeng et al.conducted a study in 2020 to investigate liquid-phase high harmonic by using a disordered linear chain and proposed a formula that could quantify the cutoff energy.Subsequently,Xia et al.proposed a statistical two-level model and revealed the role of localized charge-resonance states in high harmonic from disordered liquids.In experiments,Luu et al.reported the observation and detailed characterization of high harmonic in the EUV region from liquid water.Here,we study the high harmonic from liquid water by solving the semiconductor Bloch equations(SBE)in length gauge and investigate the modulation of the spectral shift in harmonic spectra driven by two-color laser fields.Our findings indicate that manipulating the relative phase of two-color laser fields can control the frequency and yield of odd harmonics and allow for the fine tuning of the high harmonic spectrum.We believe that our primary findings will be helpful for future studies on strong-field and

关 键 词：物理光学 高次谐波 双色激光场 光谱红移 频谱干涉 

分 类 号：O437[机械工程—光学工程]