Efficient Elimination of Fluorescence Background from Raman Spectra Collected in a Liquid Core Optical Fiber

Liquid core optical fiber (LCOF) waveguides have been used to enhance the Raman sensitivity of liquid sample measurements by more than two orders of magnitude. These waveguides can also enhance photobleaching of fluorescence in transparent liquids. We report the reduction of fluorescence intensity by more than two orders of magnitude by rapid photobleaching of solutions illuminated in an LCOF. The same solutions showed no detectable photobleaching when illuminated in a cuvette. The observed rates of photobleaching are in good quantitative agreement with theory.