基于光波合成在固体介质中产生阿秒脉冲研究

阿秒脉冲激光的产生，使人们直接测量电子动力学行为成为可能。传统基于气体介质产生阿秒脉冲的技术存在效率低与啁啾难以补偿等不足之处，而近年来在固体介质中产生阿秒脉冲的技术有望解决上述难题，成为新型阿秒光源的研究热点，此方案需要驱动光达到单周期，而现有的单路激光器难以实现，基于相位锁定的光波合成技术通过将不同光谱成分的脉冲进行相干合束，可获得小于单周期的光场。基于此，本项目拟将光波合成技术与固体介质中的阿秒脉冲产生技术相结合，从理论和实验上探索驱动光脉宽、场强、相位以及光子能量对固体高次谐波产生机制的影响。主要研究内容为：（1）搭建可见至中红外波段、单周期光波合成系统作为驱动源；（2）精确调节光波控制电子在固体介质中的带间跃迁与带内振荡过程；（3）获得少啁啾的孤立阿秒脉冲并进行脉冲特性测量。研究成果将有助于促进光波合成技术的发展，并为高效率阿秒脉冲的产生和极紫外阿秒光源的简化提供一种可行性方案。

Observation of electron dynamics becomes possible after the born of attosecond laser. Conventional technology of attosecond pulse generation, which is based on laser-induced gas ionization and recombination, facing issues in low efficiency and difficult chirp compensation. But attosecond pulse generation from solids is able to solve these issues, which becomes a hot research topic in recent years. For the driven laser for attosecond pulse generation, sub-cycle light field can be obtained by phase-locked waveform synthesizer technology, which coherently combines short pulses with different spectrum，breaks the limit on pulse duration of a single-channel laser with a single spectrum, and is beneficial for shorter attosecond pulse generation. In this project, we intend to combine the waveform synthesizer technology with solid target for the generation of attosecond pulses. The influence of driving light pulse duration, field strength, phase and photon energy on the mechanism of high-order harmonic generation in solids will be investigated. The main research content of this project includes: (1) Developing a single-cycle waveform synthesizer with spectrum covers visible to mid-infrared wavelengths;(2) Controlling the inter-band polarization and intra-band oscillation of electrons in the solid by precisely adjusting the parameters of the driven light filed; (3) Generating and characterizing attosecond pulses with low-chirp. The project will promote the development of light waveform synthesizer technology, and provide a feasible approach for high-conversion-efficiency extreme ultraviolet attosecond pulse generation with great simplicity.