A Fourier transform Raman spectrometer with visible laser excitation

TL;DR

This paper demonstrates that a Fourier transform Raman spectrometer with visible laser excitation can outperform dispersive spectrometers in sensitivity for non-luminescent samples, challenging previous beliefs about FT-Raman limitations.

Contribution

It shows that recent advances in interference filters enable FT-Raman spectrometers to be competitive with dispersive ones in the visible range, especially for non-luminescent samples.

Findings

FT-Raman can match or outperform CCD-based dispersive spectrometers in sensitivity.

High-performance interference filters improve FT-Raman viability in visible range.

The FT-Raman spectrometer offers spectral accuracy, high throughput, and cost-effectiveness.

Abstract

We present the development and performance of a Fourier transformation (FT) based Raman spectrometer working with visible laser (532 nm) excitation. It is generally thought that FT-Raman spectrometers are not viable in the visible range where shot-noise limits the detector performance and therein they are outperformed by grating based, dispersive ones. We show that contrary to this common belief, the recent advances of high-performance interference filters makes the FT-Raman design a valid alternative to dispersive Raman spectrometers for samples which do not luminesce. We critically compare the performance of our spectrometer to two dispersive ones: a home-built single channel and a state-of-the-art CCD based instruments. We demonstrate a similar or even better sensitivity than the CCD based dispersive spectrometer particularly when the laser power density is considered. The instrument possesses all the known advantages of the FT principle of spectral accuracy, high throughput, and economic design. We also discuss the general considerations which helps the community reassess the utility of the different Raman spectrometer designs.