Optical metasurfaces of subwavelength pillars have provided new capabilities for the versatile definition of the amplitude, phase, and polarization of light.In this work, we demonstrate that an efficient dielectric metasurface lens can be used to trap and image single neutral atoms with a long working distance from the lens of 3 mm.We characterize the high-numerical-aperture optical tweezers using the trapped atoms and compare with numerical computations of the metasurface-lens performance.We predict that future metasurfaces for atom trapping will be able to leverage multiple ongoing developments in metasurface design and enable multifunctional control in complex quantum information experiments with neutral-atom arrays.
Abstract Precise control and manipulation of neutral atoms are essential for quantum technologies but largely dependent on conventional bulky optical setups. Here, a multifunctional metalens that integrates an achromatic lens with large numerical aperture is demonstrated, a quarter‐wave plate, and a polarizer for trapping and characterizing single Rubidium atoms. The metalens simultaneously focuses a trapping beam at 852 nm and collects single‐photon fluorescence at 780 nm. A strong dependence of the trapping lifetime is observed on an external bias magnetic field, suggests a complex interplay between the circularly polarized trapping light and the atom's internal states. This work showcases the potential of metasurfaces in realizing compact and integrated quantum systems based on cold atoms, opening up new possibilities for studying quantum control and manipulation at the nanoscale.
Abstract Magneto-optical traps (MOTs) composed of magnetic fields and light fields have been widely utilized to cool and confine microscopic particles. Practical technology applications require miniaturized MOTs. The advancement of planar optics has promoted the development of compact MOTs. In this article, we review the development of compact MOTs based on planar optics. First, we introduce the standard MOTs. We then introduce the grating MOTs with micron structures, which have been used to build cold atomic clocks, cold atomic interferometers, and ultra-cold sources. Further, we introduce the integrated MOTs based on nano-scale metasurfaces. These new compact MOTs greatly reduce volume and power consumption, and provide new opportunities for fundamental research and practical applications.
Magneto-optical traps (MOTs), indispensable to cold-atom-based quantum computing and quantum precision measurement, are increasingly desired in compact and stable form. Particularly, the six-beam 3D-MOT, distinguished by symmetric geometry and superior trapping performance, finds particularly broad applications. Conventional implementations, however, rely on complex and bulky free-space optics, hindering miniaturization, practical assembly, and long-term stability. Here, we demonstrate a compact six-beam 3D-MOT system that employs two multifunctional optical metasurface chips to implement the optical-field functionalities required for cooling and trapping atoms. By combining two metasurface chips and a vacuum cell, a photonic-integrated cell module (PICM) is implemented as the core assembly and the volume is only" 73*73*107 mm^3" . In success, 1.3 * 10^3 Rb atoms are trapped and cooled to the temperature of ~183 μK. It should be noticed that the laser beam is guided to the metasurface through optical fiber, thus such fully fiber-coupled architecture enables straightforward and stable operations. We believe that this work would pave a practical route toward compact and portable 3D-MOT.