Knowledge Bank

The picosecond time dependence of a specific nonlinear signal generated in the fully resonant and degenerate phase conjugate configuration is presented. This particular Fourier component was explored in a previous nonlinear optical mixing experiment (H. Souma, E.J.Heilweil, R.M. Hochstrasser, J. Chem, Phys. 76(12), 5693, 1982) where it was found to contain both electronic and therrmal relaxation contributions. These portions are clearly time resolved in the present study where features arising from optical mixing and subsequent thermal grating formation and decay are exhibited. Experiments performed on the dyes Rhodamine 60 and Cresy1 Violet in ethanol as well as aqueous colloidal gold solutions will be discussed. Nonradiative energy deposition of heat into the solvent by excited state vibrational energy relaxation and thermal conduction from transiently cooling metal spheres is demonstrated by these systems.