Picosecond UV Kerr‐gated Raman spectroscopy with 280 nm laser excitation

Abstract

Raman spectra obtained by UV laser excitation above 260 nm are contaminated by spectrally overlapping UV‐excited fluorescence. Here, we demonstrate a picosecond UV Kerr‐gated Raman spectroscopy setup to suppress the fluorescence in Raman spectra excited by 280 nm laser pulses. Specifically, we use a model sample that consists of acetonitrile contaminated by a small amount of toluene for generating UV‐excited fluorescence. We were able to acquire a Raman spectrum of acetonitrile by suppressing the UV‐excited fluorescence of toluene by the action of a 1‐mm thick fused silica‐based UV Kerr gate operated by 1030 nm, ~1 ps gating pulses. These results also indicate the challenges that must be overcome in the future for realizing UV‐fluorescence‐free UV resonance Raman (UVRR) spectroscopy studies of molecules exhibiting electronic resonances around 280 nm using laser excitation wavelengths right at or close to this resonance.