Raman spectroscopic detection using a two-dimensional spatial heterodyne spectrometer

Abstract

Spatial heterodyne Raman spectroscopy (SHRS) is a type of method for the detection of Raman spectra and can achieve a very high spectral resolution. SHRS has no moving parts and can be built with rugged, compact packages, making it extremely suitable for planetary exploration. However, if a high spectral resolution is needed, a traditional one-dimensional spatial heterodyne spectrometer cannot achieve a broad bandpass because it is limited by the number of pixels of the detector. In order to solve this, two-dimensional (2-D) SHRS can be used to broaden the bandpass. A breadboard of 2-D SHRS has been designed and built, and some artificial and natural targets have been tested to learn about the detection ability of 2-D SHRS. The results show that 2-D SHRS can be used to detect Raman signals scattered from liquid and solid targets. When the Raman scattered signal is strong, it can even detect targets in containers. The detection of anti-Stokes Raman shift for sulfur and carbon tetrachloride has also been tried, and the results show that 2-D SHRS has the ability to detect anti-Stokes Raman shift below 500 cm−1. The research may have a general implication in chemical analysis and planetary exploration.