Appl Opt. 2021 Sep 20;60(27):8375-8383. doi: 10.1364/AO.433256.
Traditional micro-Raman spectroscopy technology has the disadvantages of a weak signal and low signal-to-noise ratio. To fix these issues, a cost-effective and rigorous design method is proposed in this paper, whereby a confocal micro-Raman spectroscopy system is designed and built, and a low-cost reflector and high-pass filter are introduced into the Raman signal-receiving module. The Raman light incident is fully perpendicular to the coupling lens by adjusting the reflection angle of the mirror, making the focus of the coupling lens highly conjugate with the focus of the microscope objective, to enhance the intensity of the Raman signal and improve the signal-to-noise ratio. In order to better apply this technology to the detection and study of microplastics in offshore sediments, a reflective illumination light path is used to avoid the visual interference caused by the capillary structure and opacity of the glass cellulose filter membrane. The detection and analysis of the microplastics on the glass cellulose filter membrane have been carried out by the confocal micro-Raman system designed, which is low cost and capable of obtaining good detection results and meeting the requirements of microplastics detection. The system designed in this paper is expected to be applied to the research and development of Raman detection equipment for microplastics in marine sediments, which is beneficial to promote the development of marine microplastic monitoring technology in the world.
传统的显微拉曼光谱技术存在信号弱、信噪比较低的缺点。为了解决这些问题，本文提出了一种经济高效、严谨的设计方法，设计并搭建了共焦显微拉曼光谱系统，在拉曼信号接收模块中引入了低成本的反射镜和高通滤波器。通过调整反射镜的反射角度，使拉曼光入射完全垂直于耦合透镜，使耦合透镜的焦点与显微镜物镜的焦点高度共轭，从而增强拉曼信号的强度，提高信噪 比。为了更好地将该技术应用于近海沉积物中微塑料的检测和研究，采用反射照明光路，避免了玻璃纤维素滤膜的毛细结构和不透明性引起的视觉干扰。利用设计的共焦显微拉曼系统对玻璃纤维素滤膜上的微塑料进行了检测和分析，该系统成本低，能获得良好的检测结果，满足微塑料检测的要求。本文设计的系统有望应用于海洋沉积物中微塑料的拉曼检测设备的研发，有利于推动全球海洋微塑料监测技术的发展。
