Study of the single-beam reflection technique for measuring the linear electro-optic coefficient of the nonlinear optical polymer films

Abstract

The single-beam reflection technique is usually used to measure the linear electro-optic (EO) coefficient (Pockels coefficient) in development of the EO polymer thin films. But there are some problems in the determination of the phase-shift difference between the s and p waves of a laser beam waveguided into the polymer film while a modulating voltage is applied across the electrodes in some articles, and different expressions of the linear EO coefficient have been deduced in these articles. In our research, more accurate expression of the linear EO coefficient was deduced by reasonably considering the phase shift between the s and p waves. The linear EO coefficients of several polymer thin films were measured by the reflection technique, and the results of the linear EO coefficient calculated by different expressions were compared. The limit of the single-beam reflection technique for measuring the linear EO coefficient of the polymer thin films was discussed.