Coherent anti-Stokes Raman scattering in a hollow dielectric waveguide

Hollow waveguides are shown to enhance coherent anti-Stokes Raman scattering by two to three orders of magnitude for low-pressure gases. Theoretical and experimental comparisons of signals generated by tight focusing in a cell with those generated in a hollow waveguide are preented. These arguments show that maximum conversion in the hollow waveguide occurs at pressures on the order of several atmospheres compared to greater than 50 atm for tight focusing, and for low pressures enhancements are on the order of the square ofthe waveguide length to confocal beam parameter ratio.