三色激光在充气波导管内产生孤立阿秒脉冲相位匹配条件的分析(特邀)  

Analysis of Phase-matching Conditions for Isolated Attosecond Pulses Generated by Three-color Lasers in a Gas-filled Waveguide (Invited)

作　　者：陈振煌 李保昌 张弛[1] 游家豪 金成 CHEN Zhenhuang;LI Baochang;ZHANG Chi;YOU Jiahao;JIN Cheng(School of Physics,Nanjing University of Science and Technology,Nanjing 210094,China)

机构地区：[1]南京理工大学物理学院,南京210094

出　　处：《光子学报》2024年第6期70-82,共13页Acta Photonica Sinica

基　　金：国家自然科学基金(Nos.12274230,11834004);南京理工大学基金(No.TSXK2022D005)。

摘　　要：对比优化与未优化的三色光组合发现,当高次谐波场在波导管内传播时,仅当单原子响应中始终保持单个发射峰,或者在合适相位匹配条件下单原子响应中的多余发射峰被抑制时,才能有效地产生孤立阿秒脉冲。比较不同三色光组合下产生的孤立阿秒脉冲的性能,确定基频激光(1600 nm)与其二倍频场(800 nm)、四倍频场(400 nm)的优化组合是在波导管内产生孤立阿秒脉冲的最佳组合。The interaction between ultrafast femtosecond laser pulse and an intense gas medium gives rise to High-order Harmonic Generation(HHG),which finds crucial applications in tracking ultrafast electron dynamics,molecular orbital and structural imaging,as well as observing ultrafast processes.Moreover,HHG holds significant potential in synthesizing even shorter attosecond-level pulses.Previously,single or bichromatic coherent synthesized waveform has been commonly employed to excite HHG in the gas medium for generating attosecond pulses.With advancements in relevant technologies,the coherent synthesis of multicolor lasers has gradually matured.Utilizing synthesized multicolor waveforms,HHG can be induced within a gas-filled waveguide to generate an Isolated Attosecond Pulse(IAP).Previous studies have demonstrated that,compared to two-color and single-color waveforms,optimized three-color synthesized waveform in the gas-filled waveguide can effectively extend the cutoff frequency of HHG,enhance harmonic yield,and generate high-quality IAP.However,these studies have not indicated whether arbitrarily three-color synthesized waveforms can also generate isolated attosecond pulses within the waveguide.Specifically,whether the instantaneous phase-matching mechanism of isolated attosecond pulses is correlated with the selection of three-color waveforms remains unexplored.Furthermore,it remains uncertain whether any three-color laser waveforms within the waveguide can produce isolated attosecond pulses superior to the three-color optimized waveforms,including their pulse widths and energies.In order to answer these questions,a three-color optimized waveform is selected in this paper and it is compared with two other unoptimized waveforms.Five different sets of three-color waveforms are also compared to examine the impact factors of forming an isolated attosecond pulse,i.e.,the interplay of the single-atom response of different optical waveforms and the macroscopic phase-matching conditions.The comparison between optimized and

关 键 词：高次谐波 孤立阿秒脉冲 三色激光波形 充气波导管 相位匹配机制 

分 类 号：O562.4[理学—原子与分子物理]