蓝紫光的腔增强空气喇曼光谱

喇曼光谱是一种无损、快速检测物质成分的方法。为了提高监测灵敏度,对408nm波段半导体激光器的腔增强自发喇曼散射进行了研究。利用输出功率500mW、线宽0.9nm的408nm半导体激光器作激发光,把激光耦合入共焦球面镜腔,两面共焦球面镜的反射率分别为96.5%和99.5%,部分激光返回半导体激光器形成光反馈,半导体激光器与共焦腔形成共振。对装置的光反馈过程进行了探讨,并对外腔的模式匹配和频率匹配分别进行了分析。结果表明,共焦腔内功率达到15W,功率增强了30倍;用90°探测构型收集喇曼信号,完成了空气喇曼信号检测;1s积分时间,获得N 2信号900个计数。此共振增强腔大大增强了喇曼散射信号,有潜力应用于多种气体的在线检测或高灵敏度检测。

Cavity-enhanced Raman spectroscopy of blue-violet light

Raman spectroscopy was nondestructive and rapid method for the determination of substance composition. In order to improve the sensitivity of monitoring, the cavity-enhanced spontaneous Raman scattering of 408nm band semiconductor laser was studied. 408nm semiconductor laser with output power of 500mW and linewidth of 0.9nm was used as excitation light. The laser was coupled into confocal spherical mirror cavity. The reflectivity of two-sided confocal spherical mirrors was 96.5% and 99.5%, respectively. Some lasers returned to the semiconductor laser to form optical feedback. Semiconductor laser resonated with confocal cavity. The optical feedback process of the device was discussed. The mode matching and frequency matching of the external cavity were analyzed respectively. The results show that, the power in the confocal cavity reaches 15W. The power is increased by 30 times. Raman signals are collected with 90° probe configuration. Air Raman signal detection has been completed. 900 counts of N₂ signal are obtained in 1s integration time. The results show that the resonance enhanced cavity greatly enhances the Raman scattering signal and has the potential to be used in the on-line detection or high-sensitivity detection of a variety of gases.