High-throughput compact Raman spectrometer based on polarization transformation: Development and biological trials

Abstract

As Raman spectroscopy is applied to the detection of weak signals, such as in the field of microorganism analysis, the optimization of spectrometer systems that can overcome grating polarization dependency and enhance diffraction efficiency becomes increasingly important. To address these limitations, we proposed a method that combines the polarization state transformation technique with a pulse compression grating (PCG) that exhibits high diffraction efficiency for a particular polarization state. This method not only eliminates the polarization dependence but also significantly improves the overall diffraction efficiency, enabling a remarkable spectrometer throughput of over 84 %. Additionally, we introduced a method to improve the spectral resolution based on the grating anamorphic amplification effect, achieving a 3.7 cm^-1 average spectral resolution while miniaturizing the spectrometer, and Escherichia coli colonies were tested to verify the performance of the whole system. Our research contributes to advancing the development of Raman spectrometers towards higher throughput, higher resolution, and miniaturization, enabling their application in a broader range of scenarios.