Abstract

Ferroelectric liquid crystals (FLC) attract significant attention as promising materials for different applications and rare examples of two-dimensional (2D) ferroelectrics.¹ It has been shown previously that nonlinear optical probe of second harmonic generation (SHG) can be applied to study the structure and switching behaviour of FLC.² In this study, ferroelectric properties and switching behaviour of thin planar FLC cells are studied using electrooptic (EO) and SHG intensity and interferometry measurements. The SHG in reflection and transmission through FLC cells (1-4 microns thick) is excited by an output of a Q-switched Nd:YAG laser at a wavelength of 1064 nm. A DC electric field directed along the normal to the cell was applied using the ITO electrodes. The SHG anisotropy measured for the opposite directions of the DC electric field show that the symmetry of the FLC structure changes with the field. The SHG intensity and interferometry profiles are measured as functions of the applied DC electric field. For the transmission geometry, sufficient changes in both SHG intensity and phase of the second harmonic wave are observed (Fig. 1). At the same time, no DC-induced changes in the SHG signal reflected from the FLC cells are observed.

© 2002 Optical Society of America