Anti-$\mathcal{PT}$-symmetric Kerr gyroscope

TL;DR

This paper proposes a nonlinear anti-$\mathcal{PT}$-symmetric gyroscope using spinning optical resonators, significantly enhancing sensitivity and lowering detection thresholds for ultra-sensitive rotation measurements.

Contribution

It introduces a novel nonlinear $\mathcal{APT}$ gyroscope that leverages Kerr nonlinearity and spinning resonators to surpass linear device sensitivities and detection limits.

Findings

Linear device sensitivity increased up to 1000 times.

Kerr nonlinearity breaks $\mathcal{APT}$ symmetry, lowering detection thresholds.

Nonlinear device detects much weaker rotations than linear counterparts.

Abstract

Non-Hermitian systems can exhibit unconventional spectral singularities called exceptional points (EPs). Various EP sensors have been fabricated in recent years, showing strong spectral responses to external signals. Here we propose how to achieve a nonlinear anti-parity-time ($\mathcal{APT}$) gyroscope by spinning an optical resonator. We show that, in the absence of any nonlinearity, the sensitivity or optical mode splitting of the linear device can be magnified up to 3 orders than that of the conventional device without EPs. Remarkably, the $\mathcal{APT}$ symmetry can be broken when including the Kerr nonlinearity of the materials and, as the result, the detection threshold can be significantly lowered, i.e., much weaker rotations which are well beyond the ability of a linear gyroscope can now be detected with the nonlinear device. Our work shows the powerful ability of $\mathcal{APT}$ gyroscopes in practice to achieve ultrasensitive rotation measurement.