Variation of attenuated total reflection due to the birefringence of liquid crystals by excitation of surface plasmons

Abstract

Attenuated total reflection (ATR) is a prominent effect in examining the excitation of surface plasmons. The Kretschmann–Raether and Otto configurations are implemented to generate surface plasmons and to examine the change of the refractive index of liquid crystals (LCs) by an applied field. A mixture of nematic and cholesteric liquid crystals is sandwiched between two glass substrates coated with conducting films. The minimum ATR angle changes by only 1° as the applied voltage increases to as much as 30 V (corresponding to 6×105 Vm-1), which does not agree with the calculation based on field-induced refractive-index change. This fact suggests that the orientation of LC molecules adjacent to an electrode surface is unaffected by the external field because of the strong-anchoring effect. A Jones-matrix simulation together with a multilayered structure of a LC clearly adduces this fact.