Director fluctuations in nematic liquid crystals induced by an ultrasonic wave

Abstract

The director-density coupling theory was formulated with two parameters (u(1) and u(2)) to explain the acousto-optic effect in nematic liquid crystals. The assumption that the director is not able to accompany rapid oscillations of the sound wave, so that it actually couples to the time-averaged interaction, renders it effectively a u(1)-independent theory. In this paper, we investigate a route in which the time average is postponed to the end of the calculation. This approach allows us to derive measurable quantities that depend on both u(1) and u(2).