Sublinear resonant deviations from an exceptional point degeneracy (EPD) has been recently promoted as a sensing scheme. However, there is still an ongoing debate whether the sensitivity advantage is negated by an increase in fundamental noise—especially when active elements induce self-oscillations. In this case, nonlinearities are crucial in stabilizing amplifying modes and mitigating noise effects. A drawback is the formation of hysteresis loops that signal a transition to unstable modes. This can only be alleviated by precise cavity symmetry management. Here, utilizing two coupled nonlinear RLC tanks with balanced amplification and attenuation, we demonstrate that an explicit symmetry violation, induced by sweeping the resonant detuning of the RLC tanks, reveals a hysteresis loop near the EPD whose width scales sublinearly with the intertank coupling. Our proposal re-envisions this disadvantageous feature as a sensing protocol with diverging sensitivity, enhanced signal-to-noise ratio, and self-calibration without requiring delicate symmetry control. As such, it opens avenues in metrology as well as for optical and rf switching and triggering.

Close

PrevNext

View figure in article

• Metrology
• Noise
• Dynamical systems
• Exceptional points
• Non-Hermitian systems
• Nonlinear waves
• Chaos & nonlinear dynamics
• Coupled mode theory