Electrically tunable polarization‐independent visible transmission guided‐mode resonance filter based on polymer‐dispersed liquid crystals

Abstract

AbstractA tunable polarization‐independent narrowband guided‐mode resonance filter (GMRF), consisting of a 2D subwavelength aluminum grating and a polymer‐dispersed liquid crystal (PDLC) layer is demonstrated. By taking advantage of 2D structural phase matching, the guided mode resonance occurs under both transverse electric and magnetic guided modes, we obtained polarization‐independent bandpass filtering without loss of polarization, as verified via finite‐difference time‐domain simulations. Meanwhile, we use PDLC as a property adjustable material, when the orientation of the PDLC was controlled with an applied voltage, the transform mode of the incident light changed, which enabled easy refractive index tunability. A finite element method was used to design and characterize a tunable GMRF with a transmission resonance wavelength that can be shifted from 492.31 to 505.94 nm, based on the PDLC refraction. The relationship between resonance wavelength and the PDLC refractive index exhibits a linear curve, the shape and peak of the resonance transmission curve is stable during adjustments. With the design of this structure parameter, the GMRF transmission efficiency was over 82% in the visible band.