Particle manipulation beyond the diffraction limit using structured super-oscillating light beams

TL;DR

This paper demonstrates that structured super-oscillating light beams can be arbitrarily shaped to achieve sub-diffraction focusing, enabling high-precision nanoparticle trapping and manipulation beyond traditional diffraction limits.

Contribution

It introduces a method to control the amplitude and phase of super-oscillating beams using various functions, enabling advanced particle manipulation.

Findings

Achieved sub-diffraction focusing with arbitrary beam shaping.

Enhanced trapping accuracy and stiffness compared to diffraction-limited beams.

Demonstrated high-resolution manipulation of nanometer-sized particles.

Abstract

The diffraction limited resolution of light focused by a lens was derived in 1873 by Ernst Abbe. Later in 1952, a method to reach sub-diffraction light spots was proposed by modulating the wavefront of the focused beam. In a related development, super-oscillating functions, i.e. band limited functions that locally oscillate faster than their highest Fourier component, were introduced and experimentally applied for super-resolution microscopy. Up till now, only simple Gaussian-like sub-diffraction spots were used. Here we show that the amplitude and phase profile of these sub-diffraction spots can be arbitrarily controlled. In particular we utilize Hermite-Gauss, Laguerre-Gauss and Airy functions to structure super-oscillating beams with sub-diffraction lobes. These structured beams are then used for high resolution trapping and manipulation of nanometer-sized particles. The trapping potential provides unprecedented localization accuracy and stiffness, significantly exceeding those provided by standard diffraction limited beams.