高亮度太赫兹参量产生器的研究

This project is focused on the study of injection-seeded Terahertz-wave parametric generator (is-TPG). The purpose is to solve the basic physical problem which limits the further enhancement of conversion efficiency during is-TPG. This is of great significance both theoretically and experimentally for the development of high-brightness, tunable and portable THz sources.. For the theoretical part of this study, we plan to add the term of Stimulated Brillouin Scattering (SBS) of intense laser pulses in the equations which describe the process of is-TPG，considering the inhibition of Stokes amplification in SBS on the parametric gain. At the same time, the influence of many other facts, i.e., the spatial mode and pulse duration of the pump pulse will also be taken into consideration， investigate the spatial and temporal evolution of pump, Stocks, and THz waves.. For the first time, we propose the power scaling of TPG by pumping beam shaping. Maintain the intensity of pumping power, increase the pumping energy and effective interaction volume of Stokes light by using strip-shape top-hat pumping beam, leading to the improvement of parametric efficiency. At the same time, realize close surface-emitting and reduce the absorption loss of THz dramatically.

本项目针对“种子注入式太赫兹参量产生器（is-TPG）”开展研究工作，旨在解决制约进一步提高is-TPG参量转换效率的基本物理问题，为研制高亮度、可调谐的便携式太赫兹光源提供理论和实验基础。. 首先在理论模型中加入对强激光受激布里渊散射(SBS)现象的描述，考虑SBS中斯托克斯放大对参量增益的抑制作用。考虑泵浦光空间模式及脉冲宽度等实际因素对太赫兹输出特性的影响，研究泵浦光，斯托克斯光和太赫兹光在空间和时间上的演化。. 在实验技术上，首次提出利用泵浦光整形对参量光源进行高效的功率提升（power scaling）。在保持一定的泵浦功率密度的前提下，利用长条形平顶光束增大泵浦光能量，提高斯托克斯光的有效作用体积，提高参量效率;同时实现近晶体表面输出，最大程度地减少太赫兹的吸收损耗。

本项目针对“种子注入式太赫兹参量产生器（is-TPG）”开展研究工作，旨在解决制约进一步提高is-TPG参量转换效率的基本物理问题，为研制高亮度、可调谐的便携式太赫兹光源提供理论和实验基础。研制成功了10kW量级is-TPG光源，首次提出了包含自发参量上转换效应（SPDC）的is-TPG模型，提出并构建了脉冲种子注入式太赫兹参量产生器（ips-TPG），提出了100kW量级的is-TPG设计方案。本项目对太赫兹光源实用化有很大的推进作用，在太赫兹无损检测、太赫兹成像和太赫兹器件测试领域有广阔的应用前景。