高功率窄线宽2μm超快光纤激光同步泵浦MgO:PPLN光学参量振荡器研究

3-5μm波段中红外超短脉冲激光处于分子指纹区和大气透过窗口，广泛应用于光谱分析、医学诊断、光电对抗、激光雷达等领域。目前基于1μm超快激光同步泵浦MgO:PPLN光参量振荡器是产生该波段超快激光的常用技术手段，但存在光量子亏损严重及光光转化效率较低的问题。与之相比，采用2μm激光泵浦源可大大减轻系统量子亏损，使得信号光和闲频光同时处于3-5μm波段，甚至在简并点运转理论上可以获得更高的转化效率。因此，本项目结合SESAM锁模技术与主振荡功率放大技术，基于光纤布拉格光栅器件实现~10W高功率窄线宽2μm掺Tm3+光纤超快激光，并同步泵浦MgO:PPLN光参量振荡器，旨在获得高效的瓦级功率3-5µm超快激光输出。本项目的实施为实现高效的可调谐中红外超快激光提供了新的技术途径，具有重要的应用价值和科学意义。

The 3-5μm min-infrared ultrashort pulsed laser is located in the molecular fingerprint area and the atmospheric transmission window, which is widely used in spectral analysis, medical diagnosis, optoelectronic countermeasures, lidar and other fields. At present, optical parametric oscillator synchronously pumped by 1μm lasers is a common technical means to generate ultrafast lasers in this band, but there are problems of serious optical quantum loss and light-to-light conversion efficiency. In contrast, the use of a 2μm laser pump source can greatly reduce the quantum loss of the system, and both the signal light and the idle light are in the 3-5μm. Even it can theoretically obtain higher conversion efficiency at the degenerate point. This project combines SESAM mode locking technology and main oscillation power amplification technology, and uses fiber Bragg grating devices to achieve a ~10W high-power narrow-linewidth Tm3+-doped fiber ultra-fast laser at 2μm. By synchronously pumped the MgO:PPLN optical parametric oscillator, it aims to achieve high-efficiency 3-5µm ultra-fast laser output with watt-level power. The implementation of this project provides a new technical approach for realizing an efficient tunable mid-infrared ultrafast laser, which has important application value and scientific significance.