Optical Third-Harmonic Generation in Dye Solutions

Abstract
The dependence of optical third-harmonic generation (THG) on the concentration of fuchsin and methylene blue dissolved in several solvents of different dispersions has been observed. The dye concentrations necessary to phase-match the liquid medium were found to vary in proportion to the dispersion of the pure solvent. At these phase-matched concentrations, the THG peak intensities for each dye were found to be equal. A simple model is suggested for the observed THG dependence on dye concentration and on dispersion.