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

Higher-order exceptional points in non-Hermitian systems have recently been used as a tool to engineer highsensitivity 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 ultrasensitive measurements, which could be applicable to a wide range of non-Hermitian ternary platforms.

Automated summary

By tuning the coupling parameters of a non-Hermitian system, device sensitivity to small perturbations can be enhanced, and a phase transition in exceptional points can be achieved. The adjustable coupling also leads to a sharp change in sensitivity slope, enabling precise measurement of perturbations as a function of coupling.