Electrically induced orientational instability of the director in a homeotropic nematic liquid crystal cell and its effect on surface plasmon oscillations

This study examines the electric field-induced orientational instability of the director in a homeotropically oriented nematic liquid crystal (NLC) cell. Transitions from homogeneous homeotropic state to non-homogeneous state and from non-homogeneous to homogeneous planar state were investigated. These transitions have a threshold and may exhibit hysteresis. Threshold voltages for these transitions were calculated and regions of existence of hysteresis were determined depending on the cell parameters. Increasing anchoring energy narrows hysteresis range for homeotropic to non-homogeneous transition and expands it for planar to non-homogeneous transition. The impact of the external electric field on the conditions and parameters of surface plasmon polariton (SPP) propagation in the Au-polymer film-NLC system was theoretically investigated. The effective refractive index of the SPP was found to increase with increasing anchoring energy of the NLC with the polymer film and with decreasing wavelength and applied voltage.