Raman spectroscopy by a detector-noise-limited birefringent wedge-based Fourier transform spectrometer

The development of the Fourier transform (FT) Raman spectrometer is limited by its inherent mechanism that FT Raman are generally less sensitive than grating-based ones in the visible and near-infrared range. However, the FT Raman spectroscopy technique has been applied to other scenarios where sensitivity is not the limiting factor. Here, a new development of the birefringent wedge-based FT spectrometer technique is reported, and the system's efficiency is demonstrated from the Raman spectra of a few common laboratory solvents in the cuvette as a test example. For low-light applications, the birefringent wedge-based system shows reinforced functionality compared to Michelson interferometer-based FT spectrometers in the aspects of 1) advantage due to higher accuracy in wavenumber, especially for locating peak positions; 2) multiplex advantage, which largely improves signal-to-noise ratio (SNR). The proposed setup features a stable, compact, and customizable design and provides an up-to-date reference to the development of FT Raman spectrometers from both scientific and engineering aspects.