All-angle left-handed negative refraction in Kagome and honeycomb lattice photonic crystals

TL;DR

This paper investigates all-angle left-handed negative refraction in 2D honeycomb and Kagome lattice photonic crystals, highlighting their advantages over triangular lattices, especially in the honeycomb structure with near -1 effective indices.

Contribution

It demonstrates all-angle negative refraction in honeycomb and Kagome lattices for TM2 band, showing advantages over triangular lattices, notably in honeycomb structures with broad angular and frequency ranges.

Findings

Honeycomb and Kagome lattices exhibit all-angle negative refraction in TM2 band.

Honeycomb lattice has circle-like equifrequency contours with near -1 effective index.

These structures outperform triangular lattices in certain negative refraction properties.

Abstract

Possibilities of all-angle left-handed negative refraction in 2D honeycomb and Kagome lattices made of dielectric rods in air are discussed for the refractive indices 3.1 and 3.6. In contrast to triangular lattice photonic crystals made of rods in air, both the honeycomb and Kagome lattices show all-angle left-handed negative refraction in the case of the TM2 band for low normalized frequencies. Certain advantages of the honeycomb and Kagome structures over the triangular lattice are emphasized. This specially concerns the honeycomb lattice with its circle-like equifrequency contours where the effective indices are close to -1 for a wide range of incident angles and frequencies.