Rational design of fiber-optic probes for visible and pulsed-ultraviolet resonance Raman spectroscopy.

We investigated the performance of fiber-optic resonance Raman probes with a series of experiments to determine the working curves of such probes using model analytes and to investigate the effects of absorbing media. A computer model designed to simulate these experiments is presented, and numerical results are found to be in agreement with the experimental data. Design considerations resulting from these studies are discussed, and novel designs for overcoming problems of coupling efficiency, damage threshold, and sensitivity in absorbing samples are presented. These findings are applied to the design of fiber-optic probes for ultraviolet resonance Raman spectroscopy involving nanosecond pulsed-ultraviolet excitation (225 and 266 nm). These probes have been used to collect what is, to our knowledge, the first reported fiber-optic-linked ultraviolet resonance Raman spectra of tryptophan and DNA.