Time-gated Raman spectroscopy for biomedical application under ambient or strong background light conditions

Many biomedical applications require measurements of Raman spectra tissue under ambient lighting conditions. However, the background light often swamps weaker signal. The use time gated spectroscopy based on a single avalanche photodiode (SPAD) operating in time-correlated photon counting (TCSPC) and near-infrared laser excitation was investigated for acquisition spectral images biological tissue. results obtained using animal samples (adipose muscle) show that gating modality enables measurement conditions similar quality as conventional continuous wave (CW) absence light. Optimal suppression observed gate widths 300-1000 ps. also showed time-gated able to detect subtle differences required medical diagnostics, such cancer normal While current instrument scanning grating order obtain full spectra, leading impractical times multi-wavenumber mapping, imaging can be drastically reduced by multiplexing (compressed detection) DMDs (digital micromirror devices) or SPAD arrays.