准三能级结构碟片固体激光器放大的自发辐射效应机理的基础研究

项目名称： 准三能级结构碟片固体激光器放大的自发辐射效应机理的基础研究

项目编号： No.61475057

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 无线电电子学、电信技术

项目作者： 朱广志

作者单位： 华中科技大学

项目金额： 70万元

中文摘要： 碟片固体激光器设计理念的创新，核心技术的突破解决了激光器热效应带来的诸多缺陷，实现高平均功率、高峰值功率、高光束质量激光输出的完美结合，成为工业、科研及军事领域广泛应用的优良光源。然而在向更高亮度激光输出推进的过程中，放大的自发辐射效应（ASE）已成为碟片固体激光器发展的障碍。本项目提出了准三能级结构激光晶体生热率动态变化的分析子模型，揭示生热率与材料能级结构、激光提取效率、ASE效应等热源因素之间内在联系和物理过程。并从理论和实验的角度开展激光晶体内部ASE效应光子流的形成、放大和消亡过程，发射谱线的线型函数和强度变化，以及对激光输出特性危害程度等方面的深入研究。建立多维度（空间、时域和频域）、多物理场（温度场、应力场、光波场）耦合的ASE效应综合分析模型，全面的分析、测量、评价ASE效应对碟片激光器运行特性的影响，优化系统结构参数，探索能有效抑制ASE?效应的新型碟片激光晶体单元模块。

中文关键词： 固体激光器；碟片固体激光器；放大的自发辐射效应；热效应

英文摘要： The thin disk shaped active medium avoids thermal problems occurring in conventional high power rod or slab lasers and allows the realization of lasers with high output power, high peak power and high beam quality operation, simultaneously. With all its outstanding features, thin disk lasers will not only replace classical lasers systems but also and particularly they will open new applications in industry, research and military arena. Numerical simulations and analytical consideration are important components for scaling the thin disk concept to higher power or energy. With the rapid development of thin disk laser especially high output brilliance, Amplified Spontaneous Emission (ASE) inside the disk crystal is the remaining limiting effect for thin disk design. This project proposed a dynamic thermal analysis model about quasi-three-level Yb:YAG disk crystal to reveal the inner relationship between the fractional thermal load in thin disk crystal and energy levels, laser extract efficiency, ASE and so on. Based on the temperature and gain 3D distribution in the thin disk crystal, the process about the generation, amplification and disappearance of the photon produced from ASE, the character of ASE loss and ASE emission lineshape are researched deeply in theory and experiments. The analytical model will be developed to describe, analyze and estimate the dynamic behavior of ASE in thin disk laser comprehensively. Within the model, the characters of ASE in space - time - frequency domain, and temperature, stress, gain of thin disk crystal are considered. Furthermore, based on the analytical expressions，the optimal parameters of thin disk laser system and novel structure of thin disk crystal element will be discussed.

英文关键词： Solid-state laser;thin disk laser;amplified spontaneous emission;thermal effect