Optical phase-conjugate studies of organic dyes doped in a boric acid host

Abstract

Nonlinear optical studies of Dichlorofluorescein, Arcridine Yellow, 4-(Dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran, Rhodamine 110, and Pyridine-1 dyes doped in a boric acid host have been studied at Ar⁺ laser wavelengths. Excited-state absorption was demonstrated directly by use of the pump-probe technique. Ground- and excited-state absorption cross sections and saturation intensities, phase-conjugate reflectivities, grating formation, and decay times were measured for all dyes. Phase-conjugate signals of Pyridine-1 exhibited oscillatory behavior in time, which was found to be due to heat produced during the nonra-diative relaxation of the excited molecules. Third-order susceptibilities were also estimated for the dye-doped samples from the saturation measurements. The parameters derived from the saturation data are used to predict phase-conjugate reflectivities and are compared with the measurements.