On-chip optical levitation with a metalens in vacuum

TL;DR

This paper demonstrates on-chip optical levitation of nanoparticles in vacuum using a novel ultrathin silicon metalens with high numerical aperture, enabling compact and tunable trapping for advanced quantum and sensing applications.

Contribution

It introduces a new ultrathin silicon metalens capable of optical levitation in vacuum, simplifying and miniaturizing trapping setups compared to traditional bulky optical tweezers.

Findings

Successful levitation of nanoparticles with a single metalens

Tunable trapping frequency via laser power and polarization

Transfer of nanoparticles between optical traps

Abstract

Optical levitation of dielectric particles in vacuum is a powerful technique for precision measurements, testing fundamental physics, and quantum information science. Conventional optical tweezers require bulky optical components for trapping and detection. Here we design and fabricate an ultrathin dielectric metalens with a high numerical aperture of 0.88 at 1064 nm in vacuum. It consists of 500 nm-thick silicon nano-antennas, which are compatible with ultrahigh vacuum. We demonstrate optical levitation of nanoparticles in vacuum with a single metalens. The trapping frequency can be tuned by changing the laser power and polarization. We also transfer a levitated nanoparticle between two separated optical tweezers. Optical levitation with an ultrathin metalens in vacuum provides opportunities for a wide range of applications including on-chip sensing. Such metalenses will also be useful for trapping ultacold atoms and molecules.