Broad Angle Negative Refraction in Lossless all Dielectric Multilayer Asymmetric Anisotropic Metamaterial

TL;DR

This paper demonstrates theoretically that lossless dielectric multilayer asymmetric anisotropic metamaterials can achieve broad angle negative refraction, overcoming narrow range limitations of natural materials, with potential applications in photonics.

Contribution

Proposes a novel all-dielectric multilayer structure for broad angle negative refraction, validated through numerical and full wave simulations, avoiding metals and complex fabrication.

Findings

Achieves broad angle negative refraction with lossless dielectrics.

Utilizes rotated multilayer stacks to create asymmetric elliptical iso-frequency.

Validated results through effective medium theory and full wave simulations.

Abstract

In this article, it has been theoretically shown that broad angle negative refraction is possible with asymmetric anisotropic metamaterials constructed by only dielectrics or loss less semiconductors at the telecommunication and relative wavelength range. Though natural uniaxial materials can exhibit negative refraction, the maximum angle of negative refraction and critical incident angle lie in a very narrow range. This notable problem can be overcome by our proposed structure. In our structures, negative refraction originates from the highly asymmetric elliptical iso-frequency.This is artificially created by the rotated multilayer sub-wavelength dielectric/semiconductor stack, which act as an effective asymmetric anisotropic metamaterial.This negative refraction is achieved without using any negative permittivity materials such as metals. As we are using simple dielectrics, fabrication of such structures would be less complex than that of the metal based metamaterials. Our proposed ideas have been validated numerically and also by the full wave simulations considering both the effective medium approach and realistic structure model. This device might find some important applications in photonics and optoelectronics.