标题： 超短阿托秒脉冲序列中的亚周期相位匹配效应 显示英文标题

标题： Subcycle phase matching effects in short attosecond pulse trains

摘要： 高阶谐波生成（HHG）在由强激光场驱动的气体中已成为产生阿托秒脉冲和探测物质中超快电子运动的关键技术。 通过操控HHG中涉及的微观和宏观动力学，可以定制阿托秒光脉冲的时间和光谱特性。 在本工作中，我们控制超短飞秒激光脉冲的载波包络相位（CEP），以生成短脉冲序列的阿托秒脉冲，并使用双色激光辅助光电离对其进行表征。 当我们改变驱动脉冲的CEP时，观察到光电子谱随光电子动能出现强烈且出乎意料的变化。 为了解释我们的结果，我们进行了包括微观和宏观效应的HHG模拟。 我们发现谐波的时变相位匹配和阿托秒脉冲的时间啁啾在我们的观测中起着重要作用，这为时间上解析和控制HHG过程开辟了新的前景。 显示英文摘要

摘要： High-order harmonic generation (HHG) in gases driven by intense laser fields has become a cornerstone technique for producing attosecond pulses and probing ultrafast electronic motion in matter. By manipulating the microscopic and macroscopic dynamics involved in HHG, it is possible to tailor the temporal and spectral properties of attosecond light pulses. In this work, we control the carrier-to-envelope phase (CEP) of ultrashort femtosecond laser pulses to generate short trains of attosecond pulses that we characterize using two-color laser-assisted photoionization. We observe strong and unexpected variations of the photoelectron spectra as a function of the photoelectron kinetic energy as we change the CEP of the driving pulses. To interpret our results, we carried out HHG simulations that include microscopic and macroscopic effects. We find that the time-dependent phase-matching of the harmonics and the temporal chirp of the attosecond pulses play a major role in our observation, opening new perspectives for temporally resolving and controlling the HHG process.