Simultaneous acquisition of absorption and fluorescence spectra of strong absorbers utilizing an evanescent supercontinuum

The determination of the absorption and emission spectra of strongly absorbing molecules is challenging, and the data can be biased by self-absorption of the fluorescence signal. To overcome this problem, a total internal reflection approach is proposed. The strongly absorbing sample is placed in an evanescent field of the radiation of a supercontinuum source. The collimated reflected light encodes the absorption spectrum, and the isotropic fluorescence emission is collected in a direction perpendicular to the surface at the same time. This ensures that the emitted light has a minimum possibility of self-absorption inside the sample. (C) 2016 Optical Society of America