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Non-orthogonal cavity modes near exceptional points in the far field

Authors :
Jingnan Yang
Shushu Shi
Sai Yan
Rui Zhu
Xiaoming Zhao
Yi Qin
Bowen Fu
Xiqing Chen
Hancong Li
Zhanchun Zuo
Kuijuan Jin
Qihuang Gong
Xiulai Xu
Source :
Communications Physics, Vol 7, Iss 1, Pp 1-8 (2024)
Publication Year :
2024
Publisher :
Nature Portfolio, 2024.

Abstract

Abstract Non-orthogonal eigenstates are a fundamental feature of non-Hermitian systems and are accompanied by the emergence of nontrivial features. However, the platforms to explore non-Hermitian mode couplings mainly measure near-field effects, and the far-field behaviours remain mostly unexplored. Here, we study how a microcavity with non-Hermitian mode coupling exhibits eigenstate non-orthogonality by investigating the spatial field and the far-field polarization of cavity modes. The non-Hermiticity arises from asymmetric backscattering, which is controlled by integrating two scatterers of different size and location into a microdisk. We observe that the spatial field overlap of two modes increases abruptly to its maximum value, whilst different far-field elliptical polarizations of two modes coalesce when approaching an exceptional point. We demonstrate such features experimentally by measuring the far-field polarization from the fabricated microdisks. Our work reveals the non-orthogonality in the far-field degree of freedom, and the integrability of the microdisks paves a way to integrate more non-Hermitian optical properties into nanophotonic systems.

Details

Language :
English
ISSN :
23993650
Volume :
7
Issue :
1
Database :
Directory of Open Access Journals
Journal :
Communications Physics
Publication Type :
Academic Journal
Accession number :
edsdoj.bfa518008a844c44a7ae0608ba24168a
Document Type :
article
Full Text :
https://doi.org/10.1038/s42005-023-01508-2