用于远程探测的空间外差拉曼光谱技术研究

摘要

Spatial heterodyne Raman spectroscopy (SHRS)is a new type of Raman spectroscopic detection technique with characteristics of high optical throughout,high spectral resolution,and no moving parts.SHRS is very suitable for the planetary exploration missions,which can be used to the analysis of minerals and find the biomarkers maybe exist on the surface of planeta-ry.The authors have applied the technique to the standoff Raman spectroscopic detection,analyzed the main characteristics,in-cluding spectral resolution,bandpass and signal to noise (SNR),of standoff SHRS and proved it through experiments.The bas-ic theory of standoff SHRS has been described briefly while a breadboard has been designed,built and calibrated.On the basis, the Raman spectra of some inorganic solids,organic liquids and some natural minerals have been achieved at a distance of 10 m, the SNR of the breadboard has been estimated.Due to the poor adj ustment and the defects of the optical elements,the bread-board is far away from an ideal system.But the results show that the SNR is better than 5 for most of the main Raman peaks of the samples,which can meet the basic requirement of clear positive detection of typical Raman peaks and the feasibility of stand-off SHRS has been proved.SHRS can overcome the main defects of dispersive grating Raman spectrometers and Fourier trans-form Raman spectrometers and it has a great application prospect on the detection and analysis of the planetary surface.The work of the authors can prove the potentiality of SHRS on standoff detection and can provide reference for the engineering reali-zation of standoff SHRS.%空间外差拉曼光谱技术是一种新型拉曼光谱探测技术,具有光通量大、高分辨率、无移动部件等技术优势,非常适用于行星探测任务中,对行星表面的矿物及有机物进行分析,探寻可能存在的生命标志物。作者将这一技术运用于远程拉曼光谱探测中,对远程空间外差拉曼光谱仪的光谱分辨率、光谱范围及信噪比等主要特性进行了分析与实验验证。文章对远程空间外差拉曼光谱探测的基本原理进行了简述,设计搭建了一套实验平台,并进行了定标,验证了其性能参数。在此基础上,获取了10 m处部分无机固体样品、有机样品及天然矿物的拉曼散射信号,对系统信噪比进行了估计。由于装调精度不高、光学器件缺陷等原因,系统远非理想。但测试结果表明,对于大部分样品的主要拉曼散射峰,系统信噪比优于5,基本可以满足清楚分辨典型拉曼谱峰的要求,依然可以证明这一技术的可行性。空间外差拉曼光谱技术可以弥补色散型光栅光谱仪与傅里叶变换型光栅光谱仪的主要技术缺陷,在行星表面物质探测与分析领域具有较大的应用前景。作者对于这一技术的研究一定程度上证明了空间外差拉曼光谱技术在远程探测方面的潜力,可为远程空间外差拉曼光谱仪的工程实现提供参考。