拉曼-荧光联合水下探测系统及初步试验

Development of an underwater combined Raman-fluorescence detection system and preliminary test

深海热液环境中存在着巨大的化学和热梯度,快速剧烈的混合和生物合作过程产生了多种多样的矿物合作过程,并培养了大量的化学合成微生物。激光拉曼光谱非常适合于深海热液环境矿物过程的探测,然而要对矿物与微生物作用过程进行研究,还需要与荧光光谱技术进行联合。针对深海热液的探测需求,研发了一套拉曼-荧光联合光谱水下原位探测原理样机。该联合系统主要通过双波长激光器和两个微型光谱仪实现,双波长激光器同时发射266 nm和532 nm激光,其中532 nm激光用来激发拉曼光谱,266 nm激光用来激发荧光光谱。根据波长不同,双波长激光被分为两束分别经两片石英玻璃窗口照射到海水或液体样品上。产生的拉曼和荧光光谱经后向散射收集并分别耦合到拉曼和荧光光谱仪中。整个系统集成于L790 mm×Φ270 mm的舱体内,在舱体前端有光学窗口和水密插头,舱体内部主要包括双波长激光器、光谱仪、嵌入式计算机和供电装置,甲板控制终端通过电缆实现对系统的供电、控制和数据采集。利用搭建的原理样机在实验室对海水和拟棱形藻样品进行探测,实验结果初步证明拉曼-荧光联合光谱探测装置的可行性,之后系统在青岛近岸进行了实验并获得了实验数据。下一步将优化系统并应用于深海热液环境探测。

A variety of chemosynthetic micro-organisms inhabit the deep sea hydrothermal vent environments. Steep chemical and thermal gradient, rapid and turbulent mixing and biological processes produce a multitude of diverse mineral phases. Raman spectrometer system is well suited to mineral speciation measurements and has been successfully used for the detection in deep sea hydrothermal environments so far. However, to further understand the interaction of mineral and microbial processes, a Raman system optimized for mineral identification that incorporates a fluorescence for microbial processes is needed. In order to meet the requirement of deep sea hydrothermal research, a new compact spectroscopy Raman-fluorescence combined system prototype was presented. The combined system was co mposed of a double wavelength laser which can emit both 532 nm and 266 nm wavelength, the 532 nmwavelength was used for Raman spectroscopy excitation, and the 266 nm wavelength was used for fluorescence excitation, and two miniature optical fiber spectrometer. The double wavelength laser beam was split into two paths according to the wavelength and entered into the seawater or liquid solution by different quartz window. The produced Raman and fluorescence signals were collected by a back-scattering optical set-up and coupled into Raman spectrometer and fluorescence spectrometer separately.The whole system was housed in a L790 mm×Φ270 mm capsule with an optical window on the end, and the computer, power were also contained into it. The power supply, system control, and signal delivery were provided through an 8 pins cable. Systematic experiments had been carried out with seawater and pseudo-nitzschia samples in laboratory. The results show that the Raman and fluorescence spectra could be obtained simultaneously with moderate sensitivity. Some experiment results ware acquired at Qingdao coast. It is hoped this prototype could be fully developed in hydrothermal area detection in the near future.