Resonance perfect absorption by exciting hyperbolic phonon polaritons in 1D hBN gratings.

Natural materials with hyperbolic responses can confine light with well-defined propagation directions inside the micro/nanostructure. Here we theoretically demonstrate that strong resonance absorption can be achieved in one-dimensional gratings made of hexagonal boron nitride (hBN) due to hyperbolic phonon polaritons. The radiative properties of both trapezoidal and square resonators are calculated using anisotropic rigorous coupled-wave analysis. The resonance wavelengths can be theoretically predicted and are shown to follow the anomalous or traditional scaling laws depending on the hyperbolicity. These findings may benefit the applications including photodetection, color filters, and optomechanics.