Raman converter for efficient generation of NIR laser radiation

该提案的总体主题是开发用于高脉冲的拉曼频率转换器（FC）。我们特别关注受激拉曼散射 (SRS) 来转换 Nd:YAG 激光波长，例如将 1064 nm 转换为约 1570 至 1613 nm 的波长，用于 CO2 检测。Koch 等人描述了用于 CO2 测量的脉冲激光雷达系统的当前发展。 2004 年和吉伯特等人。 2006 年。他们报告了采用外差检测的 2 µm 发射波长系统的测试测量结果。伊斯梅尔等人。 2006年开发了具有直接检测功能的2 µm系统。 Spiers 等人描述了基于连续波激光器的系统。 2002（2 µm，外差检测），Krainak 等人。 2003（1.57 µm，直接检测）。 Bufton 等人描述了早期的方法。 1983 年和杉本等人。 1993 年。所提到的系统还没有表现出所需的准确性。因此，开发新系统是必要的。拉曼激光器有望获得所需的高转换效率、光谱特性和光束质量。表 1 总结了 CO2-DIAL 激光发射机的要求。这些要求是 IPM、UNIBAS 和 DLR 开发的端到端模拟器的结果，用于计算反向散射信号属性（Di Girolamo at al. 2004a/b、Bauer et al. 2004、Summa et al. 2004、Houweling et al. 2003、DLR 2005、IPSL 2005）。该项目将扩展我们之前与德国和俄罗斯的合作，其中已经生产了多种新型非线性晶体并检查了 SRS。第一步，将根据转换效率和高脉冲能量操作来选择和表征合适的拉曼晶体。利用这些晶体，将建立拉曼激光器，以在固定频率下产生稳定的窄带激光发射。与此同时，我们将研究第二种有前景的方法。受激拉曼散射 (SRS) 允许将高能量速率从泵浦光束转移到低能量种子光束。该方法的优点是光谱和空间特性由种子激光器给出，对泵浦激光器的要求较低。

The general subject of this proposal is the development of a Raman frequency converter (FC) for high pulse. In particular we focus on stimulated Raman scattering (SRS) to convert Nd:YAG-laser wavelengths, e.g. 1064 nm into wavelengths at about 1570 to 1613 nm for CO2-detection.Current developments of pulsed lidar systems for CO2 measurements are described by Koch et al. 2004 and Gibert et al. 2006. They report on test measurements with systems at 2 µm emission wavelength with heterodyne detection. Ismail et al. 2006 developed a 2 µm system with direct detection. Systems based on continuous wave lasers are described by Spiers et al. 2002 (2 µm, heterodyne detection), and Krainak et al. 2003 (1.57 µm, direct detection). Early approaches are described by Bufton et al. 1983 and Sugimoto et al. 1993. None of the systems mentioned has demonstrated the required accuracy yet. Hence the development of new systems is necessary.Raman Lasers are promising to obtain the required high conversion efficiency, spectral properties and beam quality. A summary of requirements for a CO2-DIAL laser transmitter is given in Table 1. These requirements are the result from end-to-end simulators developed at IPM, UNIBAS and DLR to calculate the backscattered signal properties (Di Girolamo at al. 2004a/b, Bauer et al. 2004, Summa et al. 2004, Houweling et al. 2003, DLR 2005, IPSL 2005).The project will extend our previous German Russian cooperation, where a large variety of new nonlinear crystals have been produced and checked for SRS.In a first step selection and characterization of suitable Raman crystals will be made with respect to conversion efficiency and high pulse energy operation. With these crystals Raman lasers will be built up to create stable narrow-band laser emission at fixed frequencies.In parallel, a second promising method will be investigated. Stimulated Raman scattering (SRS) allows the transfer of high energy rates from a pump beam into a low energy seed beam. This method has the advantage that the spectral and spatial properties are given by the seed laser and the requirements for the pump laser are lower.