在双色场中使用相干叠加态来提高高次谐波的发射

本文提出了一种在双色场中使用相干叠加态来提高高次谐波发射效率的方法. 我们首先通过在800nm基本激光脉冲上添加一束控制激光脉冲在理论上得到双色合成激光场；其次，通过求解一维含时薛定谔方程，计算得到了体系处于不同初始态时的高次谐波谱，并结合时频分布图对其微观机理进行分析. 计算结果表明，使用相干叠加态作为体系的初始态，通过调节两束激光的相对相位可以有效实现提高高次谐波的发射效率的目的.

Enhancement of high-order harmonic emission by using a coherent superposition in a two-color laser field

We propose a method to enhance the harmonic emission efficiency by using a coherent state in a two-color laser field. Firstly, the two-color are synthesized by adding control laser pulse to the 800nm fundamental pulse. Secondly, the high-order harmonic spectra in different initial states are presented via numerically solving the one-dimensional time-dependent Schrödinger equation. At the same time, the high-order harmonic spectra are explained reasonably by means of the time-frequency distribution. Finally, the numerical results show evident advantages of using the coherent superposition state to enhance the harmonic generation efficiency through adjusting the relative phase between the two laser pulses.