Open AccessNon-Hermitian effective medium theory and complex Dirac-like cones
Author(s) -
Liyou Luo,
Yuming Shao,
Jensen Li,
RenHao Fan,
RuWen Peng,
Mu Wang,
Jie Luo,
Yun Lai
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.425862
Subject(s) - hermitian matrix , physics , dirac (video compression format) , photonics , photonic crystal , degeneracy (biology) , optics , quadratic equation , quantum mechanics , theoretical physics , mathematics , geometry , bioinformatics , neutrino , biology
In this work, we propose a non-Hermitian effective medium theory to interpret the spawning rings of exceptional points out of the Dirac cones in the band structures of photonic crystals with loss/gain. Based on this theory, we predict and demonstrate two unique types of band dispersions of fully passive photonic crystals. In one type, the exceptional ring shrinks into a complex Dirac point associated with a complex Dirac-like cone. In the other type, a point of quadratic degeneracy is realized in the imaginary frequency spectrum. Our theory provides a unified picture for the exceptional points in effective media and gives rise to novel concepts like complex Dirac-like cones in non-Hermitian photonics.