Van der Waals enhancement of optical atom potentials via resonant coupling to surface polaritons

TL;DR

This paper proposes a novel approach to atom trapping near surfaces by leveraging van der Waals interactions enhanced through resonant coupling to surface polaritons, potentially improving cavity QED experiments.

Contribution

It introduces a new trap design that exploits surface interactions rather than avoiding them, supported by numerical studies with potassium atoms and ITO surfaces.

Findings

Van der Waals interactions can be resonantly enhanced near surfaces.

Numerical simulations demonstrate potential for improved atom confinement.

Surface engineering via nanopatterning can modify atom-surface interactions.

Abstract

Contemporary experiments in cavity quantum electrodynamics (cavity QED) with gas-phase neutral atoms rely increasingly on laser cooling and optical, magneto-optical or magnetostatic trapping methods to provide atomic localization with sub-micron uncertainty. Difficult to achieve in free space, this goal is further frustrated by atom-surface interactions if the desired atomic placement approaches within several hundred nanometers of a solid surface, as can be the case in setups incorporating monolithic dielectric optical resonators such as microspheres, microtoroids, microdisks or photonic crystal defect cavities. Typically in such scenarios, the smallest atom-surface separation at which the van der Waals interaction can be neglected is taken to be the optimal localization point for associated trapping schemes, but this sort of conservative strategy generally compromises the achievable cavity QED coupling strength. Here we suggest a new approach to the design of optical dipole traps for atom confinement near surfaces that exploits strong surface interactions, rather than avoiding them, and present the results of a numerical study based on $^{39}$K atoms and indium tin oxide (ITO). Our theoretical framework points to the possibility of utilizing nanopatterning methods to engineer novel modifications of atom-surface interactions.