High-resolution stimulated Raman spectroscopy

The development of stimulated Raman spectroscopy over the past four years has clearly established the technique as a valuable tool in gas-phase Raman studies. In this brief article we have traced that development, detailed the capabilities of the stimulated Raman spectrometer, and surveyed a variety of applications of the system to problems in the gas phase. SRS is clearly most attractive in ultra-high-resolution (< 0.01 cm/sup -1/) studies that are beyond the reach of spontaneous Raman spectroscopy. Collision broadening effects dictate that such studies be performed at low pressures in order to maximize sensitivity. Currently, sample pressures below approximately 5 Torr are required in order to achieve linewidths approaching our 0.002 cm/sup -1/ instrumental resolution. Sensitivity considerations have thus limited our studies at these low pressures to relatively strong Raman scattering modes. It is our expectation that in the near future the introduction of higher-power sources and a multi-pas cell will significantly change this situation by increasing the overall sensitivity of SRS by at least two orders of magnitude. This should open up a much wider range of possible applications, which should, in turn, establish SRS as the standard for high-resolution Raman studies. 43 references.