Mechanisms of quadratic electro-optic modulation of dye-doped polymer systems

TLDR

The study aims to identify the mechanisms underlying quadratic electro‑optic modulation in dye‑doped polymer systems. The authors observe this modulation in thin polymer films, determine the Kerr coefficient using a modified Mach–Zehnder interferometer, and develop a theory of several nonlinear mechanisms to quantify their contributions. The fast, virtual electronic mechanism dominates the quadratic electro‑optic response, as shown by frequency‑dispersion measurements, and the rapid interferometric method proves useful for probing nonlinear‑optical structure–property relationships.

Abstract

We present the experimental and theoretical considerations needed to determine the mechanisms of quadratic electro-optic modulation in dye-doped polymer systems. The modulation is observed in thin dye-doped polymer films and the quadratic Kerr coefficient is determined by using a modified Mach–Zehnder interferometric technique. The theory of several nonlinear mechanisms is developed and applied to representative systems to determine the various contributions. The fast, virtual electronic mechanism is shown to be the largest contribution, as inferred from the measured frequency dispersion of the quadratic electro-optic effect. This quick interferometric method is also shown to be useful for determining nonlinear-optical structure–property relationships.