Two-way enhancement of sensitivity by tailoring higher-order exceptional points

TL;DR

This paper proposes a method to enhance the sensitivity of non-Hermitian systems by tuning coupling parameters to switch between different orders of exceptional points, enabling ultra-sensitive measurements.

Contribution

It introduces a scheme to improve device sensitivity by transitioning from third-order to second-order exceptional points through coupling adjustments.

Findings

Enhanced sensitivity achieved by tuning coupling parameters.

Abrupt phase transition from third- to second-order exceptional points.

Sharp change in sensitivity slope allows precise perturbation measurement.

Abstract

Higher-order exceptional points in non-Hermitian systems have recently been used as a tool to engineer high-sensitivity devices, attracting tremendous attention from multidisciplinary fields. Here, we present a simple yet effective scheme to enhance the device sensitivity by slightly deviating the gain-neutral-loss linear configuration to a triangular one, resulting in an abrupt phase transition from third-order to second-order exceptional points. Our analysis demonstrates that the exceptional points can be tailored by a judicious tuning of the coupling parameters of the system, resulting in enhanced sensitivity to a small perturbation. The tunable coupling also leads to a sharp change in the sensitivity slope, enabling the perturbation to be measured precisely as a function of coupling. This two-way detection of the perturbation opens up a rich landscape toward ultra-sensitive measurements, which could be applicable to a wide range of non-Hermitian ternary platforms.