# Brewster effect when approaching exceptional points of degeneracy: Epsilon-near-zero behavior

## TL;DR

This paper demonstrates that full transmission with zero phase delay, typically associated with epsilon-near-zero materials, can occur at exceptional points of degeneracy in periodic structures, offering a lossless, CMOS-compatible alternative.

## Contribution

It reveals that full transmission without phase accumulation can be achieved at exceptional points, independent of permittivity vanishing, in one-dimensional periodic dielectric structures.

## Key findings

- Full transmission without phase delay at exceptional points.
- All-angle transmission in dielectric lattices.
- Alternative to ENZ media for lossless applications.

## Abstract

We reveal that the phenomenon of full transmission without phase accumulation commonly associated with epsilon-near-zero (ENZ) materials for a plane-wave does not require vanishing of permittivity. We theoretically connect the phenomenon with condition of the Brewster effect satisfied at the edges of stop bands (so called exceptional points of degeneracy) and show that the full transmission without phase accumulation can be observed in various one-dimensional periodic structures. Particularly, exploiting the manifold of exceptional points of degeneracy in one-dimensional all-dielectric periodic lattices, we demonstrate that these structures not only offer a lossless and extremely simple, CMOS compatible alternative for some applications of ENZ media, but exhibit new properties of all-angle full transmission with zero phase delay.