Enhanced avionic sensing based on Wigner's cusp anomalies
Joshua Feinberg
U. Haifa

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 Nth-order exceptional point degeneracies (EPDs) where a small perturbation p<<1 activates an inherent sublinear response ∼ p^{1/N} >> p 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 talk. Our WCA platforms are compact, do not require a judicious arrangement of active elements (unlike EPD platforms), and, if chosen, can be cavity free.

Work done in collaboration with Rodion Kononchuk, Joseph Knee & Tsampikos Kottos
Reference: Kononchuk et al., Sci. Adv. 2021; 7 : eabg8118 4 June 2021