Fine features of optical potential well induced by nonlinearity

TL;DR

This paper proposes a method to create optical potential wells with features finer than the diffraction limit by leveraging particle nonlinearity, enabling enhanced optical trapping and manipulation.

Contribution

It introduces a nonlinear particle-based approach to generate sub-diffraction optical potential wells, surpassing traditional diffraction-limited confinement.

Findings

Potential well shape exhibits super-oscillation-like features.

Fano-resonance-like phenomena are observed.

Trap width is significantly below the diffraction limit.

Abstract

Particles trapped by optical tweezers, behaving as mechanical oscillators in an optomechanical system, have found tremendous applications in various disciplines and are still arousing research interest in frontier and fundamental physics. These optically trapped oscillators provide compact particle confinement and strong oscillator stiffness. But these features are limited by the size of the focused light spot of a laser beam, which is typically restricted by the optical diffraction limit. Here, we propose to build an optical potential well with fine features assisted by the nonlinearity of the particle material, which is independent of the optical diffraction limit. We show that the potential well shape can have super-oscillation-like features and a Fano-resonance-like phenomenon, and the width of the optical trap is far below the diffraction limit. A particle with nonlinearity trapped by an ordinary optical beam provides a new platform with a sub-diffraction potential well and can have applications in high-accuracy optical manipulation and high-precision metrology.