Polarization-dependent and angle-insensitive absorber with hyperbolic material

Abstract

A polarization-dependent and angle-insensitive absorber based on surface phonon polaritons (SPhPs) is proposed based on a sandwiched layer structure that consists of a patterned α - M o O 3 layer, a dielectric layer, and a gold layer. The absorption remains larger than 95% for TE incidence wave with incident angles from 0° to 30° in the wavelength range from 13.7 to 18.3 µm, which is a broadband absorber. At the same time, the absorption remains larger than 95% for TM incidence wave with incident angles from 0° to 60° in the wavelength range from 11.52 to 11.66 µm, which is a narrowband absorber. It is interesting that the absorber can also be used to fabricate the ideal filter of transverse electric (TE) wave in the wavelength range from 11.52 to 11.66 µm and an ideal filter of transverse magnetic (TM) wave from 15.03 to 18.37 µm. Moreover, one can combine an ideal filter of polarization and a perfect absorber into one single device. The proposed absorber shows promising performance, which has potential applications in sensing, imaging, and detection.