Kononchuk Rodion, Feinberg Joshua, Knee Joseph, Kottos Tsampikos
Wave Transport in Complex Systems Laboratory, Department of Physics, Wesleyan University, Middletown, CT 06459, USA.
Department of Mathematics and Haifa Research Center for Theoretical Physics and Astrophysics, University of Haifa, Mt. Carmel, Haifa 31905, Israel.
Sci Adv. 2021 Jun 4;7(23). doi: 10.1126/sciadv.abg8118. Print 2021 Jun.
Typical sensors detect small perturbations by measuring their effects on a physical observable, using a linear response principle (LRP). It turns out that once LRP is abandoned, new opportunities emerge. A prominent example is resonant systems operating near th-order exceptional point degeneracies (EPDs) where a small perturbation ε ≪ 1 activates an inherent sublinear response [Formula: see text] in resonant splitting. Here, we propose an alternative sublinear optomechanical sensing scheme that is rooted in Wigner's cusp anomalies (WCAs), first discussed in the framework of nuclear reactions: a frequency-dependent square-root singularity of the differential scattering cross section around the energy threshold of a newly opened channel, which we use to amplify small perturbations. WCA hypersensitivity can be applied in a variety of sensing applications, besides optomechanical accelerometry discussed in this paper. Our WCA platforms are compact, do not require a judicious arrangement of active elements (unlike EPD platforms), and, if chosen, can be cavity free.
典型的传感器通过测量对物理可观测量的影响来检测微小扰动，采用线性响应原理（LRP）。事实证明，一旦放弃LRP，就会出现新的机遇。一个突出的例子是在第n阶例外点简并（EPD）附近运行的共振系统，其中微小扰动ε≪1会在共振分裂中激活固有的亚线性响应[公式：见正文]。在此，我们提出一种基于维格纳尖点异常（WCA）的替代亚线性光机械传感方案，该异常最早在核反应框架中被讨论：在新打开通道的能量阈值附近，微分散射截面的频率依赖平方根奇点，我们利用它来放大微小扰动。除了本文讨论的光机械加速度测量外，WCA超灵敏度还可应用于各种传感应用。我们的WCA平台紧凑，不需要精心布置有源元件（与EPD平台不同），并且如果需要，可无腔。
