Light-induced second-harmonic generation in an octupolar dye

Abstract

Quasi-permanent light-induced second-order susceptibility χ⁽²⁾ of octupolar molecules is demonstrated. The octupolar molecule Ethyl Violet was oriented in a solgel matrix by a purely optical poling technique. The method consists of a seeding process based on a nonclassical holographic process with coherent two-frequency mixing. The growth of the induced χ⁽²⁾ is monitored in real time by frequency doubling of the fundamental beam in the sample. The polarization dependence of the signal is used to demonstrate the octupolar symmetry of the induced χ⁽²⁾.