Laser third harmonic generation in organic dye vapors

The phenomenon of nonlinear optical conversion of a YAG:Nd laser radiation frequency from IR to UV spectral range in naphthalene vapors was studied. T he optimum temperature of naphthalene vapors (170 degrees C) was found at w hich the pumping radiation is synchronously converted into the third harmon ic emission. A mechanism of the third harmonic generation is proposed based on the difference frequency generation in a six- photon process. The effic iency of conversion to the third harmonic generation varied within 10(-10)- 10(-8), depending on the pumping intensity and cell temperature. Nonlinear optical characteristics of naphthalene vapors were calculated for the gener ation using nonlinearities of the third and fifth order. (C) 2000 MAIK "Nau ka/Interperiodica".