Enhanced avionic sensing based on Wigner's cusp anomalies

Sensors typically detect small perturbations by measuring their effects on a physical observable in the linear response regime. As it turns out, once linear resonse is abandoned, new opportunities emerge. A prominent example is resonant systems operating near Nth-order exceptional point degeneracies (EPD), where a small perturbation ε≪1 activates an inherently sublinear response ~ε^1\N≫ ε in resonant splitting. Here we propose an alternative sublinear optomechanical sensing scheme that is rooted in Wigner’s cusp anomalies (WCA), 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 openened channel, which we use to amplify small perturbations. WCA hypersensitivity can be applied in a variety of sensing applications, besides optomechanical accelerometry focused on in this talk. Our WCA platforms are compact, do not require judicious arrangement of active elements (unlike EPD platforms), and if chosen, can be cavity free.