Enhanced sensitivity with nonlinearity-induced exceptional points degeneracy lifting
Haichuan Li, Lei Chen, Wenhao Wu, Hongteng Wang, Tianqi Wang, Yu Zhong, Feifan Huang, Gui‐Shi Liu, Yaofei Chen, Yunhan Luo, Zhe Chen
Abstract
Abstract Bifurcation of exceptional points (EPs), particularly higher-order EPs, can offer applications in metrology by amplifying sensitivity, but this method suffers from a tradeoff between sensitivity and robustness. To break this constraint, we experimentally introduce nonlinearity into the EP degeneracy lifting at the coupled electric resonators and observe a sixth-order nonlinear bifurcation which amplifies the sensitivity elevenfold compared to the conventional EP-based approach operating in the linear regime, while maintaining the degrees of freedom, thereby without cost in robustness. Moreover, we discover a chaotic dynamics near the EP due to the nonlinear contribution, which constitutes a distinct difference from the EP degeneracy lifting in the linear regime with random noise. Our study expands the scope of EP degeneracy lifting into nonlinearity, providing a paradigm to exploit the benefit of EPs.