Conversion of 30 W laser light at 1064 nm to 20 W at 2128 nm and comparison of relative power noise

All current gravitational wave (GW) observatories operate with Nd:YAG lasers with a wavelength of 1064 nm. The sensitivity of future GW observatories could benefit significantly from changing the laser wavelength to approximately 2 μm combined with exchanging the current room temperature test mass mirrors with cryogenically cooled crystalline silicon test masses with mirror coatings from amorphous silicon and amorphous silicon nitride layers. Laser light of the order of ten watts with a low relative power noise would be required. Here we use a laboratory-built degenerate optical parametric oscillator (OPO) to convert the light from a high-power Nd:YAG laser to 2128 nm. With an input power of 30 W, we achieve an output power of 20 W, which corresponds to an external conversion efficiency of approximately 67%. We find that the relative power noise spectrum marginally increases during the wavelength conversion process. Our result is an important step in the development of low-noise light around 2 μm based on existing low-noise Nd:YAG lasers.

当前所有引力波（GW）天文台均采用波长为1064 nm的Nd:YAG激光器。未来引力波天文台的灵敏度可通过将激光波长调整至约2 μm，并将当前室温下的测试质量镜替换为采用非晶硅与氮化非晶硅层作为镜涂层的低温冷却晶体硅测试质量块，得到显著提升。该方案需要功率约为十瓦、相对功率噪声较低的激光。本研究使用实验室自研的简并光学参量振荡器（OPO）将高功率Nd:YAG激光器输出的激光转换至2128 nm波长。当输入功率为30 W时，本装置获得了20 W的输出功率，对应的外部转换效率约为67%。研究发现，在波长转换过程中，相对功率噪声频谱仅有小幅提升。本研究成果为基于现有低噪声Nd:YAG激光器开发2 μm波段低噪声激光迈出了重要一步。

搜集汇总

背景与挑战

背景概述

该数据集记录了激光波长转换实验，将30W的1064nm激光转换为20W的2128nm激光，外部转换效率约为67%，并比较了转换过程中的相对功率噪声。实验旨在支持未来引力波观测站的灵敏度提升，通过简并光学参量振荡器实现高效波长转换，为基于现有低噪声Nd:YAG激光器开发2μm波段低噪声光源提供了重要步骤。