High-throughput multimodal wide-field Fourier-transform Raman microscope

Raman microscopy is a powerful analytical technique for materials and life sciences that enables mapping the spatial distribution of the chemical composition of a sample. State-of-the-art Raman microscopes, based on point-scanning frequency-domain detection, have long (similar to 1 s) pixel dwell times, making it challenging to acquire images of a significant area (e.g., 100 x 100 mu m). Here we present a compact wide-field Raman microscope based on a time-domain Fourier-transform approach, which enables parallel acquisition of the Raman spectra on all pixels of a 2D detector. A common-path birefringent interferometer with exceptional delay stability and reproducibility can rapidly acquire Raman maps (similar to 30 min for a 250 000 pixel image) with high spatial (<1 mu m) and spectral (similar to 23 cm(-1)) resolutions. Time-domain detection allows us to disentangle fluorescence and Raman signals, which can both be measured separately. We validate the system by Raman imaging plastic microbeads and demonstrate its multimodal operation by capturing fluorescence and Raman maps of a multilayer-WSe2 sample, providing complementary information on the strain and number of layers of the material. (c) 2023 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement