A cavity-microscope for micrometer-scale control of atom-photon interactions

TL;DR

This paper introduces a cavity-microscope device that enables micrometer-scale control of atom-photon interactions within a high-finesse cavity, enhancing spatial resolution and opening new avenues for quantum technologies.

Contribution

It proposes and demonstrates a novel cavity-microscope system that achieves spatial control of atom-light coupling beyond the cavity mode waist using local Floquet engineering.

Findings

Achieved micrometer-scale atom-photon coupling control

Demonstrated cavity-assisted atomic measurements with high spatial resolution

System compatible with various atomic species and standard cavity setups

Abstract

Cavity quantum electrodynamics offers the possibility to observe and control the motion of few or individual atoms, enabling the realization of various quantum technological tasks such as quantum-enhanced metrology or quantum simulation of strongly-correlated matter. A core limitation of these experiments lies in the mode structure of the cavity field, which is hard-coded in the shape and geometry of the mirrors. As a result, most applications of cavity QED trade spatial resolution for enhanced sensitivity. Here, we propose and demonstrate a cavity-microscope device capable of controlling in space and time the coupling between atoms and light in a single-mode high-finesse cavity, reaching a spatial resolution an order-of-magnitude lower than the cavity mode waist. This is achieved through local Floquet engineering of the atomic level structure, imprinting a corresponding atom-field coupling. We illustrate this capability by engineering micrometer-scale coupling, using cavity-assisted atomic measurements and optimization. Our system forms an optical device with a single optical axis and has the same footprint and complexity as a standard Fabry-Perot cavity or confocal lens pair, and can be used for any atomic species. This technique opens a wide range of perspectives from ultra-fast, cavity-enhanced mid-circuit readout to the quantum simulation of fully connected models of quantum matter such as the Sachdev-Ye-Kitaev model.