Subwavelength Position Sensing Using Nonlinear Feedback and Wave Chaos

Abstract

We demonstrate a position-sensing technique that relies on the inherent sensitivity of chaos, where we illuminate a subwavelength object with a complex structured radio-frequency field generated using wave chaos and nonlinear feedback. We operate the system in a quasiperiodic state and analyze changes in the frequency content of the scalar voltage signal in the feedback loop. This allows us to extract the object’s position with a one-dimensional resolution of =10 000 and a two-dimensional resolution of =300, where is the shortest wavelength of the illuminating source.