Time-resolved Raman spectroscopy of trinitrotoluene detected by Silicon Photomultiplier

Silicon Photomultiplier (SiPM) is a new type of solid state photodetector developed rapidly in recent decades, and has the potential to replace photo multiplier tube (PMT) in the Raman detection. A time-resolved Raman spectroscopy system based on a Silicon Photomultiplier (SiPM) was established in order to limit the influence of intense fluorescence on Raman spectroscopy, and alleviate the high dark count rate (DCR) problem of the SiPM. The variation of the Peak-to-Background Ratio (PBR) of Raman peaks along with counting time was investigated using trinitrotoluene (TNT) as the sample. Results indicate that with counting time increasing, the PBR of Raman peaks is increasing first and then decreasing, finally changing slowly. When counting time is 400 ps, a best PBR is achieved for the Raman peaks. The results are superior to that achieved by the commercial Raman spectrometers and the methods used in the literature. Also, the dark counts system collected are comparable to PMT. The method proposed in the paper is capable of reducing the high fluorescence background and the effects of SiPM's high DCR to a great extent, facilitating a marked improvement in the Raman PBR.