Exploiting the combined dynamic and geometric phases for optical vortex beam generation using metasurfaces

TL;DR

This paper introduces a hybrid metasurface design that combines dynamic and geometric phases to generate optical vortex beams with tunable polarization control, enhancing flexibility and application potential.

Contribution

It proposes a novel hybrid phase approach in metasurfaces, enabling tunable polarization control in optical vortex generation, which was not achievable with previous single-phase methods.

Findings

Hybrid design achieves vortex generation with polarization tunability.

Structural parameters correlate with vortex topological charge.

Experimental results confirm design flexibility and control.

Abstract

The generation of optical vortex beams is pivotal for a myriad of applications, encompassing optical tweezing, optical communications, and quantum information, among others. The metasurface-based approach has realized significant advancements in vortex production, utilizing either dynamic or geometric phases. The dynamic design exhibits indifference to the polarization state of incident light, while the geometric design is inextricably tied to it. In the study, we put forth the proposition that combining dynamic and geometric phases could unlock the potential of metasurface design in generating optical vortices. A hybrid design that harnesses the combined dynamic and geometric phases can attain the same objective while offering tunable functional control over the polarization of light. We establish a correlation between the structural parameters of metasurface and the topological charge of the resulting vortices. The experimental results fully demonstrate the design's flexibility and its effective control over the polarization constraints of incident light. Our research uncovers the capacity for vortex generation through the manipulation of hybrid phases introduced by metasurfaces, indicating significant potential for the design of optical devices and the future advancement of innovative optical applications.