Title: Subwavelength Position Sensing Using Nonlinear Feedback and Wave Chaos

Seth Cohen

Short Abstract
We demonstrate a position-sensing technique that utilizes the inherent sensitivity of chaos, where we illuminate a subwavelength dielectric object in a cavity with a complex structured radio-frequency field generated using wave chaos and an electronic nonlinear circuit. We operate the system’s dynamics in a two-tone quasi-periodic state and analyze changes in the frequency content of the scalar voltage signal in an electronic feedback loop. These frequencies allow us to extract the object’s position in a cavity with a one-dimensional resolution of λ/10,000 and a two-dimensional resolution of λ/300, where λ is the shortest wavelength of the illuminating source (15 cm). Possible extensions of this work include three-dimensional subwavelength position-sensing, through-wall tracking, and subwavelength optical microscopy.