Parity-Time Symmetry Breaking in Coupled Nanobeam Cavities

TL;DR

This paper investigates PT symmetry breaking in coupled nanobeam cavities, revealing exceptional points that enable applications like unidirectional light propagation, enhanced sensor sensitivity, and single-mode lasers in photonic circuits.

Contribution

It demonstrates the occurrence of PT symmetry breaking and exceptional points in coupled nanobeam cavities, proposing new photonic device applications.

Findings

Observation of exceptional points during PT symmetry tuning

Potential for unidirectional light propagation

Enhanced sensitivity at exceptional points

Abstract

The parity-time symmetry (PT symmetry) breaking phenomenon is investigated in a coupled nanobeam cavity system. An exceptional point is observed during the tuning of the relation of the gain/loss and coupling strength of the closely placed nanobeam pairs. The PT symmetry concept can be applied to realize unidirectional light propagation and single mode operation lasers, which may allow for a new way to harness the optical signal in photonic integrated circuits. Otherwise, operating at this particular exceptional point, sensitivity of tiny perturbation detection can be enhanced greatly compared with conventional sensors.