Differential laser-induced perturbation spectroscopy using a deep-ultraviolet excimer laser

Here we demonstrate a unique optical sensing scheme based on deep-UV photochemical perturbation in combination with difference spectroscopy. Applying a sequence of optical probing, UV-laser-induced perturbation, and repeat optical probing coupled with difference spectroscopy provides a new spectral signature. We show a selective (sevenfold difference) optical response using a fluorescence probe for binary mixtures of organic dyes, and generate complementary spectral information derived from Raman scattering of the dipeptide glycine-glycine. We further extend the methodology to fluorescence-based imaging of an organic matrix.