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 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.
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.
Metasurfaces made of subwavelength silicon nanopillars provide unparalleled capacity to manipulate light, and have emerged as one of the leading platforms for developing integrated photonic devices. In this study, we report on a compact, passive approach based on planar metasurface optics to generate large optical trap arrays. The unique configuration is achieved with a meta-hologram to convert a single incident laser beam into an array of individual beams, followed up with a metalens to form multiple laser foci for single rubidium atom trapping. We experimentally demonstrate two-dimensional arrays of 5 × 5 and 25 × 25 at the wavelength of 830 nm, validating the capability and scalability of our metasurface design. Beam waists ∼1.5 µm, spacings (about 15 µm), and low trap depth variations (8%) of relevance to quantum control for an atomic array are achieved in a robust and efficient fashion. The presented work highlights a compact, stable, and scalable trap array platform well-suitable for Rydberg-state mediated quantum gate operations, which will further facilitate advances in neutral atom quantum computing.
Optical tweezer arrays of laser-cooled and individually controlled particles have revolutionized atomic, molecular, and optical physics. They afford exquisite capabilities for applications in quantum simulation of many-body physics, quantum computation, and sensing. Underlying this development is the technical maturity of generating scalable optical beams, enabled by active components and a high numerical aperture objective. However, such a complex combination of bulk optics outside the vacuum chamber is very sensitive to any vibration and drift. Here, we demonstrate the generation of a 3 × 3 static tweezer array with a single chip-scale multifunctional metasurface element in vacuum, replacing the meter-long free space optics. Fluorescence counts on the camera validate the successful trapping of the atomic ensemble array and showcase a promising strategy for integrated photonics with cold atom systems. The introduction of a polarization independent dual-wavelength metasurface significantly enhances fluorescence collection efficiency while reducing experimental complexity. This approach paves the way for scalable neutral atom platforms and offers a compelling route towards the realization of next generation quantum metasurfaces.
Miniaturized spin-exchange relaxation-free (SERF) atomic magnetometer is an ultra-sensitive device for biomagnetic dynamic measurements, yet it still remains challenging in realizing easy-to-align and compact optical configuration while maintaining high sensitivity. In this study, we demonstrate a multi-functional metafiber, consisting of a compact metalens assembled on the facet of an optical fiber, for flexible and high-performance pump light delivery and manipulation in atomic magnetometers for the first time. By tailoring transmission and phase profiles of nanopillars, the metafiber simultaneously enables broadband collimation and polarization manipulation from 770 to 894 nm, a spectrum regime that covers most commonly used alkali metals in quantum technologies. We integrate the metafiber with a SERF atomic magnetometer and achieve magnetic field measurement with a sensitivity of 51.12 fTHz−1/2(@31.5 Hz). Beyond optically interfaced quantum systems, the demonstrated highly compact and easy-to-align multifunctional metafiber can also find widespread classical applications such as wavelength-multiplexing fiber-optic communications, fiber sensing and fiber lasers.
Abstract Neutral atom trapping is of importance in precision quantum metrology and quantum information processing where the atom can be viewed as an excellent frequency reference. However, creating tunable optical traps compatible with the optical nanostructures is still a challenge. Here, by introducing the chiroptical effects of a plasmonic structure into atom trapping, an active tunable potential for 3D stable optical trapping at the nanoscale is demonstrated. By altering the incident light from left‐ to right‐handed circularly polarized, the tunable range of position and potential of the trapped atoms can reach ≈60 nm and ≈0.51N mK (N denotes input power with unit mW), respectively. In addition, the blue‐detuned circularly polarized light guarantees the ultralow scattering rate and ultralong trapping lifetime. The trap centers are about hundreds of nanometers away from the structure surface, which ensures the stability of the trapping system due to the ignorable surface potential. This chiral‐based tunable atom trapping system broadens the application of chiral metamaterials and has important impact on all‐optical modulation, atomic on‐chip integration, manipulation of cold atoms, and quantum many‐body systems.
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.