基于全光学方法测量任意波形激光脉冲的研究

项目名称： 基于全光学方法测量任意波形激光脉冲的研究

项目编号： No.11474002

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 滕浩

作者单位： 中国科学院物理研究所

项目金额： 90万元

中文摘要： 激光脉冲是具有振幅、包络、振荡频率、相位等物理信息的电磁波，当脉冲宽度仅仅只有几个周期时，决定激光与物质相互作用的是光场分布，利用受控的光场来操作和控制物质内部电子的运动特性和发展过程是未来超快研究中最重要的研究方向。要实现光场调控，首先要对光场分布进行测量，而传统的自相关方法如FROG或SPIDER只能获得脉冲的包络信息，不能实现对脉冲光场的测量；阿秒条纹相机虽然可以对脉冲光场进行扫描，但它是基于对光电子能谱进行测量，该实验系统庞大，造价昂贵、且不易操作。为此，本项目将利用气体高次谐波的截止区光谱对驱动脉冲电场峰值非常敏感的特点，在主激光脉冲中叠加一个待测脉冲后，精确扫描二者之间的延迟将待测脉冲的电场分布投影到截止区光谱的频移上，反演后就可以得到待测脉冲的电场分布等重要信息。该方法可以实现对任意波形、任意光波段的激光脉冲进行扫描测量，对开展受控光场与物质相互作用的研究具有重要的意义。

中文关键词： 阿秒脉冲；飞秒激光；高次谐波；相干合成；超快光学

英文摘要： The spectrum in cut-off region in HHG is very sensitive to the highest E-field strength in laser pulse. Using a CEP stabilized high-energy few-cycle laser pulse by interfering a relatively weak test pulse, the peak intensity of the main pulse will be modified and thus the frequency of the harmonic cut-off will be shifted by an amount proportional to the test pulse field strength at the time that coincieds with the main pulse peak. By scanning the delay the test pulse and main pulse, the field of the test pulse is mapped onto intensity modulation in the HHG cut-off spectrum. From the modulated HHG spectrum obtained, we can got the reconstructed spectrum an temporal waveform. Comparization with conventional methods such as FROG and SPIDER, which require an ultrathin crystal, limiting the efficiency and thus signal to noise ratio, and insensitivity to the carrier envelope phase. As comparison with attosecond streaking camera which is based on the detection of photoelectrons, the cost of this method is much cheaper and easy to got signal,quicker acquistion,simpler experimental configuration,and higher SNR without generation of single attosecond pulse.This novel all-optical method will be developed as measure the complete temporal field evolution of arbitrary ultrafast optical pulses with attosecond resolution.

英文关键词： attosecond pulse;femtosecond laser;high harmonic generation;coherent synthesis;ultrafast optics