谐振泵浦Ho:LLF晶体2μm波段自注入锁定稳频双波长开关激光器

The output of Ho doped solid state lasers is at 2μm band, which has the advantages of eye-safety and good atmosphere penetrability. This makes Ho doped solid state lasers have important applications in the fields of remote sensing, laser communications, and photoelectric countermeasure. To solve the critical technical issues of fast switching between the on/off-line wavelength sources in compact 2μm differential absorption lidar, the project aims to investigate the operating mechanism and dynamics of a self-injection-locking and frequency-stabilized dual-wavelength switching laser based on diode resonantly-pumped Ho:LLF crystals. The proposed laser can perform the fast, stable dual-wavelength switching of synchronous pulse output at 2µm band, which can meet the requirements of the seed laser source of compact differential absorption lidar. The main research contents include: (1) by introducing the novel self-injection-locking mechanism, we firstly develop the vectorial laser dynamics model to deeply analyze the basic issues involving the generation, coupling interaction and delay control of dual-wavelength orthogonal-polarization pulses. The optimal design of self-injection-locking dual-wavelength laser is presented for achieving the energy equilibrium and pulse synchronization output. (2) by exploiting the new scheme of hollow-core photonic crystal fiber gas-cell as frequency-locking element, we study experimentally the promising frequency-stabilization technology to stabilize the self-injection-locking dual-wavelength output of resonantly-pumped Ho laser. (3) By combining the high-speed electro-optic polarization switching method, we study experimentally the frequency-difference tunable dual-wavelength switching operation of the self-injection-locking, frequency-stabilized laser. We finally demonstrate that the fast on/off-line wavelength switching can be realized only by one compact diode-pumped Ho solid state laser.

钬(Ho)掺杂固体激光器输出波长为2μm波段，人眼安全，大气穿透性好，在激光遥感、通信和光电对抗等领域具有重要应用背景。面向小型化差分吸收雷达在线/离线波长光源快速切换的关键技术，本项目研究基于二极管激光谐振泵浦Ho:LLF晶体的自注入锁定稳频双波长开关激光器工作机理及特性，实现2μm波段双波长稳频快速切换的同步脉冲发射，满足小型化差分吸收雷达种子源的需求。主要研究内容包括：(1)引入自注入锁定新机理，率先发展矢量激光动力学模型，全面分析双波长正交偏振脉冲激光的产生、耦合及延迟控制等物理问题，完成能量均衡与脉冲同步输出的自注入锁定双波长激光器的优化设计。(2)采用空芯光子晶体光纤气体池稳频新方案，系统地研究谐振泵浦Ho激光器自注入锁定双波长输出的频率稳定技术。(3)结合高速电光偏振开关方法，实验研究频差可调的自注入锁定稳频双波长开关，实现一台激光器即可完成在线/离线波长光源的快捷切换。

钬(Ho)掺杂激光器输出波长为2μm波段，在激光遥感和大气通信领域具有重要应用背景。面向小型化差分吸收雷达在线/离线波长光源快速切换的关键技术，项目研究谐振泵浦Ho:LLF晶体的自注入锁定稳频双波长开关激光器工作机理及特性，实现双波长稳频快速切换的2μm波段脉冲发射。.主要内容包括：引入自注入锁定机理，发展Ho:LLF晶体的矢量激光动力学模型，分析双波长正交偏振脉冲的产生、耦合及延迟控制等物理问题，完成能量均衡与脉冲同步输出的双波长激光器的优化设计。采用光纤气体池稳频方案，研究激光器双波长输出的频率稳定技术。结合电光偏振开关方法，研究频差可调的自注入锁定稳频双波长开关，实现一台激光器即可完成在线/离线波长的快捷切换。.重要结果包括: 在理论上，完成了Ho:LLF激光偏振开关动力学、正交偏振脉冲同步与交替输出特性，以及自注入机制激光动力学建模分析。发展了矢量激光动力学模型，研究了光腔各向异性诱发激光本征模的正交偏振开关和瞬态延迟响应。提出了光注入方法，有效抑制偏振模竞争和缩减偏振开关时间。确定了被动调Q晶体的偏振配置方案，发现了正交偏振脉冲的时间同步输出特性，讨论了脉冲交替输出的能量比和时间间隔的调控方法。指出了采用交叉偏振注入法，随着反馈系数增大可实现偏振模式的能量均衡输出，讨论了同偏振和交叉偏振注入、以及正反馈和负反馈注入条件下激光动力学特性。阐明了正交偏振输出脉冲的时间同步性和能量均衡性的关键科学问题，为实验提供了可行方案。在实验上，完成了谐振泵浦2μm波段双波长正交偏振开关激光器的设计与测量，开展了锁模激光的频率稳定和双波长同步锁模研究。获得了Ho:LLF双波长正交偏振输出，测得2052nm波长π偏振和2066nm波长σ偏振的最大输出功率分别为299mW和126mW，实现了双波长功率比接近1:1的均衡输出。改变腔内各向异性增益与损耗，实现了正交偏振的切换输出。测得最小脉冲宽度为326ns，最大重复频率为24kHz，最大平均能量为28µJ。