Funneling Light Through a Subwavelength Aperture with Epsilon-Near-Zero Materials

TL;DR

This paper demonstrates that epsilon-near-zero (ENZ) materials can efficiently funnel light through subwavelength apertures, offering a simpler alternative to complex nanofabrication techniques for photonic integration.

Contribution

It provides the first experimental evidence of ENZ-enhanced transmission through a subwavelength slit and offers a theoretical analysis of this phenomenon.

Findings

First direct observation of bulk-ENZ-enhanced transmission

ENZ materials enable efficient light coupling at subwavelength scales

Potential for simplified photonic device integration

Abstract

Integration of the next generation of photonic structures with electronic and optical on-chip components requires the development of effective methods for confining and controlling light in subwavelength volumes. Several techniques enabling light coupling to sub-wavelength objects have recently been proposed, including grating-, and composite-based solutions. However, experi-mental realization of these couplers involves complex fabrication with \sim 10nm resolution in three dimensions. One promising alternative to complex coupling structures involves materials with vanishingly small dielectric permittivity, also known as epsilon-near-zero (ENZ) materials. In contrast to the previously referenced approaches, a single at layer of ENZ-material is expected to provide effcient coupling between free-space radiation and sub-wavelength guiding structures. Here we report the first direct observation of bulk-ENZ-enhanced transmission through a subwavelength slit, accompanied by a theoretical study of this phenomenon. Our study opens the door to multiple practical applications of ENZ materials and ENZ-based photonic systems.