Resonance Raman measurements utilizing a deep UV source

Raman scattering techniques have long been used as unique identifiers for spectral fingerprints of chemical and biological species. Raman lidar has been utilized on a routine basis to remotely measure several constituents in the atmosphere. While Raman scattering is very reliable in uniquely identifying molecules, it suffers from very small scattering cross sections that diminish its usefulness at increased ranges and decreased concentrations of the species of interest. By utilizing a resonance Raman technique, where the laser excitation is tuned near an electronic absorption band, it is possible to increase the Raman scattering cross section. An optical parametric oscillator (OPO) with a UV tuning range of ~220 nm - 355 nm has been utilized to explore the wavelength dependence of Raman scattering for diamond, water, benzene, and toluene. Resonance enhancements of the Raman spectra have been studied.