Circularly-Symmetric Alternating Optical Vortex Lattices and their Focusing Characteristics

TL;DR

This paper experimentally demonstrates circularly-symmetric alternating optical vortex lattices with controllable topological charges, revealing unique focusing patterns and potential applications in particle manipulation and imaging.

Contribution

It introduces a novel method to generate and control circularly-symmetric alternating optical vortex lattices with arbitrary topological charges and specific focusing characteristics.

Findings

Focusing fields exhibit a period of 4 for different n values.

Central bright spot size varies with n, especially smaller for multiples of 4.

Intensity and phase distributions are tunable via radial and azimuthal parameters.

Abstract

Generating controllable optical vortex (OV) lattices (OVLs) with arbitrary-order topological charge (TC) and superior optical characteristics are highly desirable for various applications. Here, we report an experimental realization of circularly-symmetric OVLs with alternating positive and negative TCs of order +/-n, referred to the $n$th-order circularly-symmetric alternating OVL (CSAOVL). The focusing fields of such CSAOVLs exhibit the very interesting patterns with a period of 4 for different n values, and their intensity and phase distributions can be regulated using the radial and azimuthal parameters. Particularly, the formed central bright spot in the focusing fields of those CSAOVLs with n equaling to a multiple of 4 is observed to be much smaller than a Gaussian spot. The results can promote significantly the exploration of structured OVLs and provide potential applications in particle manipulation, imaging, and the realization of complex interactions between optical lattices and microscope particles such as atoms and micro- or nano-particles.