基于Cherenkov辐射级联准腔相位匹配共线差频产生高能太赫兹的研究

太赫兹波因具有高穿透性、相干性、低能性等特点，在生物医学、医学诊断等领域具有重要的应用价值，但长期以来由于受到有效太赫兹波产生源的束缚使其应用受限。本课题在前期已初步完成周期性晶体共线差频产生太赫兹源的基础上，针对如何有效地产生高效率、高能量、可调谐的太赫兹源的机制及关键技术等方面进行研究。鉴于级联差频过程可以突破Manley-Rowe条件限制及Cherenkov匹配的潜在优点，课题拟在Cherenkov辐射级联条件下，研究利用准腔相位匹配共线差频产生高效高能太赫兹。通过建立产生高能太赫兹的模型，在准腔相位匹配找到合适的腔结构，分析级联机制如何获得高阶级联效应，在Cherenkov辐射最佳匹配条件下获得高效高能可调谐的太赫兹源。项目实施预期能获得高能太赫兹源的产生机制及新技术，为太赫兹在医学诊断等领域的应用奠定基础。

Terahertz has important application value in biomedicine, medical diagnosis and other fields because of its high penetration, coherence and low energy. For a long time, its application has been limited due to the restriction of the effective terahertz wave generator. On the basis of the periodic crystal collinear difference frequency generation of terahertz, the mechanism and key technologies of how to effectively generate high efficiency, high energy and tunable terahertz source at room temperature have been studied. In view of the fact that the cascaded difference frequency process can break through the constraints of Manley Rowe condition and the potential advantages of Cherenkov matching, the subject plans to study the generation of high-energy terahertz by using quasi cavity phase matching collinear difference frequency under the condition of Cherenkov radiation cascading. In this paper, we build a model to generate high-energy terahertz, find the appropriate cavity structure in the quasi cavity phase matching, analyze how to obtain the high-class coupling effect in the stage alignment system, and obtain the high-efficiency and high-energy tunable terahertz source under the best matching condition of Cherenkov radiation. The implementation of the project is expected to obtain the generation mechanism and new technology of high-energy terahertz source, and lay the foundation for the application of terahertz in medical diagnosis and other fields.