DISPERSION FILTER FOR SPECTRAL AND SPATIAL-RESOLUTION OF PURE ROTATIONAL RAMAN-SCATTERING

A new filtering technique for Raman spectroscopy utilizes atomic vapor to suppress strong elastic and Rayleigh scattering while simultaneous ly resolving individual rotational Raman lines. Filtered images captur e high-resolution spectral information in one dimension and spatial re solution in the other dimension. The filter is based on resonance enha nced dispersion, where the index of refraction varies dramatically. In a simple prism geometry the vapor disperses incident radiation accord ing to frequency. A mercury-vapor-based dispersion filter has been fab ricated, modeled, and demonstrated to capture pure rotational Raman sc attering from CO2. (C) 1998 Optical Society of America.