Dynamics of the acousto‐optic effect in a nematic liquid crystal

Abstract

In a nematic liquid crystal cell, the application of an ultrasonic wave induces a rotation of the director, leading to a change in the optical transmission through the cell. In this study, we investigate the dynamic response of the optical intensity after the ultrasonic wave is switched on or off. Our experiments show that the optical intensity follows a double‐exponential function of time, indicating that the system has two relaxation modes with widely different time scales. The fast mode has an amplitude and time scale qualitatively consistent with the dynamics of the Fréedericksz transition, but the slow mode shows novel behaviour associated with the acousto‐optic effect.

Acknowledgments

We would like to thank B. Houston, R. Corsaro, and H. Simpson for helpful discussions. This work was supported by the Office of Naval Research and the Naval Research Laboratory.