Secondary electro-optic effect in liquid crystalline cholesteric blue phases

Abstract

The electro-optic Kerr effect in cubic blue phase liquid crystals comprises two components with different characteristic response times: one attributed to the primary (purely electro-optic) effect and another attributed to the secondary, or indirect (photoelastic) effect. Through simultaneous measurement of the polarized reflection spectrum and transmitted phase, we show that the contribution of the secondary electro-optic effect can be as large as 20% of the total change in refractive index, and that it is suppressed in the polymer-stabilized blue phase. Our results show the importance of stabilizing the lattice structure to realize blue-phase devices with fast response.