A perfect absorber induced by critical coupling between phonon polaritons of molybdenum trioxide and photons of photonic crystal

In this paper, we proposed and numerically verified a perfect absorber composed of unstructured nature hyperbolic material α-MoO 3 layers on top of photonic crystal (PhC) layers and reflecting mirrors, which can attain nearly perfect absorption of 99.94% at 24.7 terahertz (THz) in Transverse Magnetic (TM) mode. We demonstrate that the absorption efficacy can be regulated by adjusting structural parameters, meeting the requirements of the absorption spectrum spanning from the microwave to the infrared (IR) region. This study presents an exemplary application of natural hyperbolic materials in the realm of perfect absorption, offering significant potential for use in sensing and detection.