Dispersion in the Nonlinear Susceptibility of GaP near the Reststrahl Band

Abstract

This paper describes a continuation of earlier work, in which we reported measurements of the intensities of mixed frequencies from a 6328 \AA{} beam and various infrared frequencies near the lattice reststrahl resonance, and in which we gave a theory for the dispersion of the nonlinear susceptibility which governs the mixing process near the reststrahl resonance. With more infrared frequencies, with data on the anti-Stokes side as well as on the Stokes side, and with improved techniques, we can now give a more meaningful comparison with theory. These new data provide additional confirmation of the theory for the dispersion of the nonlinear susceptibility. We also describe the apparatus more fully, and we demonstrate some incidental features of the mixing.