All-angle collimation of incident light in $\mathbf{\mu}$-near-zero metamaterials

TL;DR

This paper demonstrates that in μ-near-zero metamaterials, incident light is collimated at all angles with energy flow perpendicular to the interface, especially near the permeability resonance, revealing a novel light transmission property.

Contribution

It introduces the concept of all-angle collimation of incident light in μ-near-zero metamaterials using inhomogeneous wave theory, extending previous findings in ε-near-zero materials.

Findings

All-angle collimation occurs for s-polarized light in μ-near-zero metamaterials.

Collimation is observed near the wavelength where permeability approaches zero.

The effect is similar to that previously found in ε-near-zero metamaterials.

Abstract

We use the theory of inhomogeneous waves to study the transmission of light in $\mu$-near-zero metamaterials. We find the effect of all-angle collimation of incident light, which means that the vector of energy flow in a wave transmitted to a $\mu$-near-zero metamaterial is perpendicular to the interface for any incident angles if an incident wave is s-polarized. This effect is similar to the all-angle collimation of incident light recently found through a different theoretical framework in $\varepsilon$-near-zero metamaterials for a p-polarized incident wave [S. Feng, Phys. Rev. Lett. 108, 193904 (2012)]. To provide a specific example, we consider the transmission of light in a negative-index metamaterial in the spectral region with a permeability resonance, and show that all-angle collimation indeed takes place at the wavelength for which the real part of permeability is vanishingly small.