Emergent asymmetries and enhancement in the absorption of natural hyperbolic crystals

Abstract

The effects of the anisotropy orientation in hyperbolic media have only recently emerged as a way to control and manipulate several optical effects. Here, we show from both experimental and theoretical evidence that highly oriented-asymmetric absorption can be induced in simple crystal quartz. This can be achieved by controlling the orientation of the anisotropy with respect to the surface of the crystal at infrared regions where crystal quartz behaves as a hyperbolic medium. What is perhaps most intriguing here is that not only is the absorption asymmetric, but it can also be significantly enhanced. Finally, we also show various mechanisms through which the asymmetry in the absorption can be optimized, such as controlling the thickness of the crystal. Such phenomena are key for directional-dependent optical devices and present a pathway for engineering angle-encoded detection and sensing.