Submicrosecond Electric Switching of Large Birefringence in the Isotropic Phase of Ferroelectric Nematics

Abstract Conventional nonpolar nematic liquid crystals, widely known for their successful display applications, are not well suited for fast electro‐optical switching because of the slow (milliseconds) field‐off relaxation of the director. In this work, sub‐microsecond field‐on and field‐off switching of a large birefringence (≈0.1) is demonstrated by applying a moderate electric field (30−100) Vµm⁻¹, to an isotropic film of a ferroelectric nematic material. This highly efficient electro‐optical switching is rooted in the recently discovered field‐induced isotropic to ferroelectric nematic phase transition. The demonstrated sub‐microsecond switching of ferroelectric birefringence induced by field (FBIF) has the potential for applications in fast‐switching electro‐optic devices, such as phase modulators, light shutters, beam steerers, switchable optical compensators.