Abstract
Abstract
Negative-index materials (NIMs) support optical anti-parity-time (anti-
) symmetry even when they are lossless. Here we prove the feasibility in achieving higher-order exceptional points (EPs) in lossfree waveguide arrays by utilizing the anti-
symmetry induced by NIM. Numerical simulation about a third-order EP fits well with the coupled-mode theory. A scheme of achieving fourth-order EPs is also discussed. This work highlights the great potential of NIM in overcoming the obstacles of ordinary non-Hermitian optics, and the possibilities of combining anti-
,
, and Hermitian couplings for various purposes.
Funder
National Natural Science Foundation of China
the Scientific Research Foundation of Nanjing Institute of Technology
Subject
Condensed Matter Physics,Mathematical Physics,Atomic and Molecular Physics, and Optics