Multi-particle manipulation with a three-dimensionally tunable metalens array

Optical tweezers, renowned for their exceptional precision in non-contact manipulation, are pivotal tools for exploring the microscopic world and finding widespread applications in physics and life sciences. However, realizing compact and integrated optical trapping systems with dynamic multifunctionality remains highly challenging. Metasurfaces, with their unprecedented ability to precisely control light fields on planar platforms, open up promising opportunities for developing compact, high-performance optical tweezers. Nevertheless, conventional metasurface-based metalenses possess fixed phase profiles, limiting their adaptability for versatile optical manipulation. In this work, we leverage the phase-change material Sb 2 S 3 , whose reversible refractive index modulation enables dynamic tuning of the metalens phase profile. Under excitation by linearly polarized light at 1550 nm, active modulation of the refractive index of Sb 2 S 3 nanopillars enables dynamical switching of the focal point in three-dimensional space. Furthermore, we construct a 2×2 metalens array, allowing dynamic reconfiguration of the particle trapping pattern between “X”-shaped and “Y”-shaped geometries. This tunable metasurface-based optical tweezers platform provides a versatile approach for optical manipulation, holding strong potential for applications in cellular control and broader areas of the life sciences.