基于超快激光成丝中THz双折射效应的THz偏振调控机制研究

申请人课题组率先发现了飞秒激光成丝中的THz双折射现象，为实现宽带、高强度THz波偏振调控技术提供了新思路。但目前对这一现象还缺乏理解，亟待深入研究。为此，项目围绕光丝内THz双折射现象出现的实验条件、THz折射率时空演变物理机制、调控光丝辐射THz偏振性质的物理参数等关键科学问题，按照实验规律—>物理机制—>调控方法的总体思路开展研究工作。目标建立描述光丝中THz双折射现象的物理模型、掌握基于成丝现象的THz波偏振调控方法，并完成THz波偏振调控演示实验装置一套。项目研究一方面将有助于丰富对于成丝过程中的光与物质相互作用动力学的基础科学认知，进一步拓展该领域的前沿；另一方面，实现一种简单易行的THz脉冲偏振调控技术，推动宽带、高强度THz源在物理、化学、材料、生物、医药等领域波谱分析和成像的广泛应用。

The applicant has recently found THz birefringence inside femtosecond laser filament in air. It has provide a new approach of THz polarization manipulation. However, the underlying physics of this novel phenomenon has not been understood yet. Hence, being devoted to confirm the experimental conditions of the emergence of THz birefringence, to uncover the fundamental physics and to develop the new polarization control technique, the proposed project will carry out systematic study of the spatial-temporal properties of the THz pulse, laser beam and the plasma column during the filamentation process. Propagation dynamics of both the femtosecond laser pulse and THz pulse will be investigated theoretically, too. Besides, method of enhancing THz amplitude and controlling the birefringence will be explored, leading to the construction of ultra-broad band, intense THz source with a feasibility of polarization manipulation. The success of the proposed project will not only deepen the understanding about the fundamental physics of femtosecond laser interaction with matters, but also promote the application of filamentation based THz pulse in various domains, including physics, chemistry, material science and bio-medic. The applicant is a world-known scholar working at the forefront of femtosecond laser filamentation. The applicant is well experienced in the research on the THz pulse generation by femtosecond laser filamentation and is equipped with excellent facility. The success of the proposed project is hence ensured.