Electrooptical Measurement of χ⁽³⁾ in Polymers with Conjugated π-Electron Systems

Abstract

Electrooptical measurements of χ⁽³⁾(ω;0,0,-ω) have been performed with films of polydiacetylene and poly-p-phenylenevinylene (PPV). In a reflection-technique the electric field induced birefringence is measured, wherefrom χ⁽²⁾ and χ⁽³⁾ can be calculated. This technique which is a modification of an established χ(²)-method presents some advantages compared to wave-guiding-techniques or complicated THG and DFWM.

In the investigated polymers χ⁽³⁾ is caused by fast electronic processes in the conjugated π-electron systems and the measured values should be comparable to those obtained by all-optical methods (THG, DFWM) in the nonresonant area.