Perfect absorption in lossy anisotropic materials

Current state of art for perfect absorption is based on manipulating the incoming wave (which needs to be coherent) or the medium (needs to match impedance at optical frequency) or both. We show (Opt. Express. 27, 9561-9569 (2019)) perfect absorption of incoherent plane wave by planar semi-infinite slab based on the Brewster phenomenon. Lossless isotropic media support Brewster wave but cannot absorb energy. On the other hand, introducing loss in the medium causes Brewster wave to evolve directly into the leaky Zenneck surface wave. We demonstrate that anisotropic media with extra degrees of freedom in material parameters can bring the Zenneck wave back to Brewster wave even in the presence of loss. Our approach identifies potential classes of lossy anisotropic media who support this behavior and shows that the operating frequency of the proposed system is independent of physical dimensions. Our results show that many existing natural materials exhibit this effect at different frequencies from far-infrared to deep ultraviolet regimes.