Wide-angle absorber achieved by optical black holes using graded index photonic crystals

We present the design and characterization of a wide-angle optical absorber in the near infrared regime, based on an optical board embedded with periodic optical black holes using graded index photonic crystals. The implementation of the proposed system is validated within the lowest band. The finite element method is employed to simulate the electromagnetic wave propagation of the designed device. Moreover, the influences of the angles of wave incidence and periods of optical black holes on absorption efficiency are studied. The results show that the optical absorber using a thin metal coating at the bottom exhibits a high-efficiency absorption performance over a wide range of angles. Since the optical black hole is composed of the full dielectric materials, it eases the experimental fabrication.