发表机构
V. E. Zuev Institute of Atmospheric Optics SB RAS; Institute of spectroscopy RAS（俄罗斯科学院西伯利亚分院大气光学研究所; 俄罗斯科学院光谱研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过实验揭示高压气体中双色飞秒激光成丝的超连续谱动态调控机制，发现多丝化导致复杂光谱依赖及原子与分子气体差异，为可控超短脉冲产生提供新途径。
AI 中文摘要
双色激光成丝被认为是实现光谱深度变换和产生超短光脉冲的一种有前景的策略，这对于在阿秒物理和超快光谱学中开发有效控制宽带相干辐射的方法至关重要。我们展示了在高达11 atm压力的Ar、N2和CO2气体中，基频（800 nm）和二次谐波（400 nm）飞秒脉冲共线双色成丝过程中产生的超连续谱光谱动力学实验结果。我们证明，在高压气体中过渡到多丝化会定性改变颜色分量之间的相互作用动力学。我们证明，观察到的不是成丝过程中展宽光谱的简单合并，而是双色超连续谱形状对脉冲间时间延迟的复杂非单调依赖，包括在400 nm区域的选择性辐射抑制。首次识别出原子气体和分子气体中双色成丝动力学的显著差异。特别是在CO2中，光谱变换在皮秒级脉冲间延迟下得以保持，这归因于分子转动波包对有效非线性极化率的强烈贡献。我们的结果证明了在原子和分子气体中，随着压力变化，光谱能量可控再分配和超连续谱个别区域动态关闭的可能性，这填补了对多双色丝时空演化理解的空白，并为受控形成超短激光脉冲铺平了道路。
英文摘要
Twocolor laser filamentation is considered a promising strategy for deep transformations of the spectrum and generating ultrashort light pulses, which is critically important for developing effective methods to control broadband coherent radiation in attosecond physics and ultrafast spectroscopy. We present the results of our experiments on the study of the spectral dynamics of supercontinuum generated during collinear twocolor filamentation of femtosecond pulses at the fundamental (800 nm) and second harmonic (400 nm) frequencies in Ar, N2, and CO2 gases at pressures up to 11 atm. We demonstrate that the transition to multiple filamentation in high pressure gases qualitatively changes the interaction dynamics between the color components. We demonstrate that instead of a simple merging of spectra broadened during filamentation, a complex, nonmonotonic dependence of the shape of the twocolor supercontinuum on the time delay between pulses is observed, including selective suppression of radiation in the 400 nm region. For the first time, significant differences are identified between the dynamics of twocolor filamentation in atomic and molecular gases. Particularly, in CO2, spectral transformation is preserved at picosecond interpulse delays, which is explained by the strong contribution of molecular rotational wave packets to the effective nonlinear polarizability. Our results demonstrate the possibility of controlled redistribution of spectral energy and dynamic switching off of individual regions of supercontinuum in atomic and molecular gases as their pressure changes, which fills the gap in understanding the spatiotemporal evolution of multiple two color filaments and paves the way for the controlled formation of ultrashort laser pulses.
