Modulation of the Dielectric Constant of the Liquid Crystal System by Means of Photochromism

Abstract

Photochemical, reversible modulation of a dielectric constant of liquid crystals was demonstrated. This novel method of readout of photonic information as electric output is based on the principle of photochemically triggered phase transition in liquid crystals. Thus, the phase transition of a host liquid crystal, 4-cyano-4'-pentylbiphenyl (5CB), was induced by a partial photo-isomerization of a small amount of 4-butyl-4'-methoxyazobenzene (BMAB) doped in as a perturber. This isothermal phase transition brought about a change in the dielectric constants. The change in the dielectric constants is reversible corresponding to the trans-cis photoisomerization.