Ultraviolet optical spanner with focused vortex metalens

Abstract

The miniaturized integrated ultraviolet (UV) optical spanner (OS) plays a crucial role in attaining both high resolution and precise control. In this study, we propose an UV OS scheme with focused vortex metalens. Employing this approach, we have designed a UV metalens with a numerical aperture (NA) of 1.1. Optical forces acting on particles within the focused spiral ring and the trapping potential were computed using the finite-difference time-domain (FDTD) method. Our designed metalens effectively trapped SiO₂ particles with a 60 nm radius within the optical vortex (OV) ring. The maximum optical forces acting on the SiO₂ particles were 3.45 pN W⁻¹, 3.45 pN W⁻¹, and 1.1 pN W⁻¹ in the x, y, and z-directions, respectively. Furthermore, we examined the correlation between the optical forces exerted by the OS and particle diameter, particle refractive index, as well as incident power. We also discussed the correlations between azimuthal force, rotational velocity, and torque with changes in topological charge. These findings present innovative technical solutions for the precise manipulation of viral particles and nanoparticles.