Polarization-sensitive multifunctional metasurface integrating optical tweezers and perfect vortex beam for particle manipulation

Abstract This paper proposes a multifunctional metasurface device that monolithically integrates optical tweezers (OT) and optical spanners (OS) with perfect vortex beams (PVBs) on a single, compact platform, significantly enhancing the stability of particle manipulation at micro and nanoscales. In contrast to conventional sequential optical setups, our design overcomes the limitations of system complexity and alignment sensitivity. Conventional vortex beams suffer from limitations due to their intensity distribution diameter varying with topological charges, whereas PVBs overcome this drawback through a constant ring-shaped intensity profile. Under illumination at a wavelength of 532nm, the metasurface simultaneously generates a focused beam and a vortex beam. Numerical simulations demonstrate that the optimized metasurface produces a diffraction-limited focal spot (radius: 0.36 μm) at z = 6.5 μm through high-numerical aperture (NA) focusing (NA = 0.73), and forms an OS beam with a ring-shaped intensity distribution at z = 10 μm, whose helical phase gradient drives particle rotation around the optical axis. Validated via Maxwell stress tensor calculations, polystyrene nanoparticles (radius: 100nm) exhibit three-dimensional trapping stiffnesses of 375.56 pN·μm −1 ·W −1 (lateral) and 69.84 pN·μm −1 ·W −1 (longitudinal) in the OT region. In the OS region, a non-zero tangential force induced by the phase gradient enables off-axis particle trapping and rotational manipulation. The designed metasurface achieves a PVB generation efficiency of 67%, with beam diameters (2.4 μm) independent of topological charges and mode purity ranging from 58% to 81%. By monolithically integrating multiple functionalities, this device simplifies traditional multi-component optical systems and demonstrates broad application potential in biomedicine (e.g., cell manipulation), chemical catalysis, and quantum mechanics.