空间外差光谱技术凭借超高光谱分辨率、 高通量、 瞬态探测、 无运动部件等优势, 在星际暗物质及大气微量气体成分等微弱光谱信号检测方面得到广泛应用。 为了探索一种基于空间外差光谱技术实现物质拉曼光谱(RS)快速、 直接检测的可行性, 选择三叶草作为测量对象, 使用一体化HEP-765-S空间外差光谱系统作为拉曼特征光谱探测器, 配合特定波长激光器搭建系统, 开展拉曼特征光谱直接测量实验。 首先使用Gaussview6.0构建三叶草所含主要色素: 叶绿素a、 叶绿素b、 α-胡萝卜素和β-胡萝卜素的分子结构, 然后利用Gaussian16获取优化的仿真RS, 分析四种色素最强拉曼谱峰的波段范围, 确定四种成分的强信号特征波段为1 537～1 800 cm-1。 根据激发光源与拉曼位移的理论关系, 结合探测系统759～769 nm的检测波段范围, 计算出用波长680 nm的激光器作为光源激发拉曼信号, 可保证四种色素强特征拉曼信号正好落在探测范围, 且可避开光源瑞利散射光及荧光干扰的影响。 最终购置中心波长为680.28 nm的激光器与HEP-765-S空间外差光谱系统搭配开展三叶草强峰拉曼信号的直接检测实验。 实验结果表明: 搭建系统能够实现三叶草RS的直接测量, 但是所测拉曼信号强度偏弱, 这主要是两方面原因造成: (1)由于所用激光器的输出功率峰值偏小, 约为130 mW； (2)所用HEP-765-S空间外差光谱系统为一体化设计仪器, 软硬件系统及参数固化后不能进行调整, 仪器数据采集的最大积分时间偏小, 设定值为832 ms。 光源功率不够大且仪器积分时间小共同导致采集信号偏弱。 通过与仿真光谱比较, 实测光谱在使用空间外差系统探测波段与三叶草叶片内四种主要色素拉曼信号叠加的包络基本一致, 中央主峰与两端次峰都符合较好, 实测光谱与仿真光谱具有较好一致性, 说明采用空间外差系统对物质拉曼信号进行快速、 直接检测具有可行性。

The spatial heterodyne spectroscopy technology has been widely used in the detection of weak spectral signals such as interstellar dark matter and atmospheric trace gas components by virtue of its ultra-high spectral resolution, high through put, transient detection, and no moving parts. In order to study the feasibility of real-time Raman spectroscopy (RS) based on spatial heterodyne spectroscopy, and the integratedspatial heterodyne spectroscopy system HEP-765-S is used as the Raman characteristic spectrum detector. Firstly, Gaussview6.0 was used to construct the molecular structure of the main pigments in clover: chlorophyll a, chlorophyll b, α-carotene and β-carotene. Then Gaussian16 was used to obtain the optimized simulated RS, analyze the band range of the strongest Raman spectrum peaks of the four pigments, and determine the strong signal characteristic bands of the four components were 1 537~1 800 cm-1. According to the theoretical relationship between the excitation light source and the Raman displacement, combined with the detection band range of the detection system of 759~769 nm. It is calculated that the laser with the wavelength of 680 nm can be used as the light source to stimulate the Raman signal, which can ensure that the Raman signals with the strong characteristic of four pigments fall within the detection range, and avoid the influence of Rayleigh scattering light and fluorescence interference of the light source. Finally, a laser with a central wavelength of 680.28 nm and space heterodyne spectrum system HEP-765-S were purchased to conduct the direct detection experiment of clover strong peak Raman signal. The results show that the system can directly measure the RS of clover, but the measured Raman signal strength is weak, which is mainly caused by two reasons: one is that the peak power of the laser used is relatively small. Second, the space heterodyne spectrum system HEP-765-S is an integrated design instrument. The software and hardware system and parameters cannot be adjusted after curing, and the maximum integral time of instrument data collection is 832 ms. The acquisition signal is weak due to the insufficient power of the light source and the small instrument integral. Compared with the simulated spectrum, the measured spectrum in the detection band of the spatial heterodyne system is basically consistent with the envelope superimposed by Raman signals of four main pigments in clover leaves. The main peak ends with time are in line with the good, the measured spectra and simulation spectrum has a good consistency, using the spatial heterodyne system for material Raman signal is quick, direct detection is feasible.