Acousto-optical and acousto-dielectric effects in a nematic liquid crystal

This paper deals with the optical transmission and the dielectric effects in a nematic liquid crystal film (MBBA) of homeotropic state subjected to ultrasound. As in the case of the application of shear vibration, it is found that not only the transmitted light intensity through the film but also the dielectric constant and the tanδ of the film change with ultrasound intensity. There exists a threshold sound pressure above which the effects are appreciable. The threshold sound pressure is almost inversely proportional to the film thickness and the ultrasound frequency.