Transmission gap, Bragg-like reflection, and Goos-H\"{a}nchen shifts near the Dirac point inside a negative-zero-positive index metamaterial slab

TL;DR

This paper studies how the unique Dirac point in negative-zero-positive index metamaterials affects reflection, transmission, and Goos-H"{a}nchen} shifts, revealing phenomena like a transmission gap and tunable beam shifts with potential optical applications.

Contribution

It introduces the effects of the Dirac point on optical properties in NZPIM, including a transmission gap and controllable GH shifts, which are novel insights in metamaterial optics.

Findings

Transmission exhibits a gap near the Dirac point.

GH shifts can be positive or negative and are tunable.

Resonances enhance GH shifts away from the Dirac point.

Abstract

Motivated by the realization of the Dirac point (DP) with a double-cone structure for optical field in the negative-zero-positive index metamaterial (NZPIM), the reflection, transmission, and Goos-H\"{a}nchen (GH) shifts inside the NZPIM slab are investigated. Due to the linear Dirac dispersion, the transmission as the function of the frequency has a gap, thus the correspond reflection has a frequency or wavelength window for the perfect reflection, which is similar to the Bragg reflection in the one-dimensional photonic crystals. Near the DP, the associated GH shifts in the transmission and reflection can be changed from positive to negative with increasing the wavelength. These negative and positive shifts can also be enhanced by transmission resonances, when the frequency is far from that at the DP. All these phenomena will lead to some potential applications in the integrated optics and optical devices.