Dual polarization perfect absorption in hBN crystals supported by guided mode resonance

Abstract A dual polarization perfect absorber based on hexagonal boron nitride (hBN) crystals within the mid-infrared (M-IR) spectral regime has been displayed numerically. The newly developed absorber comprises hBN film applied on a substrate, with a spacer layer between the film and a series of dielectric square arrays. The absorber has nearly 100% polarization-insensitive absorption at 6.9515 μm for light under normal incidence, related to the guided mode resonance effect. Such perfect absorption is interpreted physically by examining electromagnetic field profiles. Furthermore, the impact of structural parameters on the absorption profiles was systematically analyzed to offer practical insight into fabrications. This research lays the foundation for developing a novel hBN-based absorber utilizing guided-mode resonance, which will benefit the potential application within the M-IR region.