Asymmetric Transmission Control in Layered Natural Hyperbolic Crystals

Hyperbolic materials have been the focus of intense discussion of the past two decades due to their unprecedented ability to manipulate optical fields and the energy flow of light in very unusual and exciting ways¹; making them excellent candidates for novel infrared detectors² and light-harvesting devices³. More recently, the effect of the anisotropy direction with respect to the surface of the material has been shown to be a strong agent for controlling wave propagation⁴. Here, we investigate the electromagnetic properties of a structure composed of two optically active materials. Each material is a hyperbolic crystal whose anisotropy axis is rotated with respect to its surface. The rotation gives control of the transmission spectra to obtain two frequencies where at one frequency, light with positive incident angles is transmitted while it is absorbed for negative incident angles and the reverse occurs at a second frequency. This, in turn, can lead to tunable output collimated beams that are directional dependent even when light is incident at all angles (here we will show examples of this using a point source). From these discoveries, we expect that our structure can be applied as an efficient frequency or angle selector, demultiplexer or optical filter.

1. Nature Photonics 7, 948–957 (2013)

2. ACS Appl. Mater. Interfaces 2017, 9, 41, 36137–36145

3. A Mayer et al 2010 Nanotechnology 21 145204

4. ACS Photonics 2018, 5, 12, 5086–5094