Heating in Nanophotonic Traps for Cold Atoms

Abstract

Laser-cooled atoms that are trapped and optically interfaced with light in nanophotonic waveguides are a powerful platform for fundamental research in quantum optics as well as for applications in quantum communication and quantum information processing. Ever since the first realization of such a hybrid quantum nanophotonic, heating rates of the atomic motion observed in various experimental settings have typically been exceeding those in comparable free-space optical microtraps by about three orders of magnitude. This excessive heating is a roadblock for the implementation of certain protocols and devices. Its origin has so far remained elusive and, at the typical atom-surface separations of less than an optical wavelength encountered in nanophotonic traps, numerous effects may potentially contribute to atom heating. Here, we theoretically describe the effect of mechanical vibrations of waveguides on guided light fields and provide a general theory of particle-phonon interaction in nanophotonic traps. We test our theory by applying it to the case of laser-cooled cesium atoms in nanofiber-based two-color optical traps. We find excellent quantitative agreement between the predicted heating rates and experimentally measured values. Our theory predicts that, in this setting, the dominant heating process stems from the optomechanical coupling of the optically trapped atoms to the continuum of thermally occupied flexural mechanical modes of the waveguide structure. Beyond unraveling the long-standing riddle of excessive heating in nanofiber-based atom traps, we also study the dependence of the heating rates on the relevant system parameters. Our findings allow us to propose several strategies for minimizing the heating. Finally, our findings are also highly relevant for optomechanics experiments with dielectric nanoparticles that are optically trapped close to nanophotonic waveguides.

Published version. 35 pages (including appendices), 7 figures, 18 tables, and 3 pages of supplemental material

References in corpus (20)

• Millikelvin cooling of an optically trapped microsphere in vacuum
• Waveguide-coupled single collective excitation of atomic arrays
• Improved constraints on non-Newtonian forces at 10 microns
• Demonstration of a memory for tightly guided light in an optical nanofiber
• Two-dimensional Bose-Einstein condensate in an optical surface trap
• Cavity-Assisted Back Action Cooling of Mechanical Resonators
• Storage of fiber-guided light in a nanofiber-trapped ensemble of cold atoms
• Generation and detection of a sub-Poissonian atom number distribution in a one-dimensional optical lattice
• Trapping of Ultracold Atoms in a Hollow-core Photonic Crystal Fiber
• Near-field coupling of a levitated nanoparticle to a photonic crystal cavity
• Near-ground-state cooling of atoms optically trapped 300nm away from a hot surface
• Cold-atom based implementation of the quantum Rabi model
• Observation of ultra-strong spin-motion coupling for cold atoms in optical microtraps
• Fictitious magnetic field gradients in optical microtraps as an experimental tool for interrogating and manipulating cold atoms
• Non-additivity of optical and Casimir-Polder potentials
• Quadratic Quantum Hamiltonians: General Canonical Transformation to a Normal Form
• Observation of quantum spin noise in a 1D light-atoms quantum interface
• Spin-optomechanical coupling between light and a nanofiber torsional mode
• Dipole force free optical control and cooling of nanofiber trapped atoms
• Quantization of the elastic modes in an isotropic plate

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• Reduced volume and reflection for bright optical tweezers with radial Laguerre-Gauss beams
• Imaging and localizing individual atoms interfaced with a nanophotonic waveguide
• Scalable Networking of Neutral-Atom Qubits: Nanofiber-Based Approach for Multiprocessor Fault-Tolerant Quantum Computer
• State-Insensitive Trapping of Alkaline-Earth Atoms in a Nanofiber-Based Optical Dipole Trap
• Optomechanical cooling and self-stabilization of a waveguide coupled to a whispering-gallery-mode resonator
• A perspective on integrated atomo-photonic waveguide circuits
• Coupling of Light and Mechanics in a Photonic Crystal Waveguide
• Theory of waveguide-QED with moving emitters
• Probing Surface-Bound Atoms with Quantum Nanophotonics
• Feedback-cooling the fundamental torsional mechanical mode of a tapered optical fiber to 30 mK
• Torsional optomechanical cooling of a nanofiber
• Low-energy scattering of ultracold atoms by a dielectric nanosphere
• Hybrid Trapping of Cold Atoms with Surface Forces and Blue-Detuned Evanescent Light on a Nanophotonic Waveguide
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