Electro-tunable optical diode based on photonic bandgap liquid-crystal heterojunctions

Abstract

An optical heterojunction photonic bandgap (PBG) structure consisting of an anisotropic nematic layer sandwiched between two cholestric liquid-crystal layers with different helical pitches was investigated. A half-wave phase retarders layer made of planar nematic liquid crystal (NLC) was sandwiched two PBG CLC layers with the same sense of helix handedness but different pitches. The optical diode action in the optical heterojunction anisotropic structure (OHAS) was analyzed. With its advantages of easy fabrication and electro-tunability, it was found that the structure has wide potential application in photonic devices that make use of propagation-direction dependent operation.