Theoretical investigation of the effect of hexagonal boron nitride on perfect absorption in infrared regime

In this paper, we theoretically studied that the perfect interferenceless absorption in hexagonal boron nitride can be realized at different wavenumbers and incident angles. For examples, the absorption can reach 0.999 in the wavenumber band 500-750 cm−1 when the angle of incidence is 70°, and the absorption can beyond 0.9999 in the wavenumber band 1800-2400 cm−1 when the angle of incidence is 59.5°. The orientation of the optical axis provides an active way to manipulate the optical properties of the hexagonal boron nitride. This method does not only work for hexagonal boron nitride, but also works for other anisotropic materials. The results of this paper will give us a comprehensive understanding of hexagonal boron nitride.