The cooperative Lamb shift in an atomic nanolayer

TL;DR

This paper reports an experimental study of the cooperative Lamb shift in an atomic nanolayer, revealing how virtual photon exchange causes measurable shifts dependent on layer thickness, advancing understanding in non-linear optics.

Contribution

It provides the first experimental measurement of the cooperative Lamb shift in a tunable atomic nanolayer, demonstrating scalable cooperative interactions.

Findings

Measured the cooperative Lamb shift and Lorentz shift in atomic nanolayers.

Confirmed the interference effect with a spatial frequency of 2k.

Showed potential for scalable non-linear optical systems.

Abstract

We present an experimental measurement of the cooperative Lamb shift and the Lorentz shift using an atomic nanolayer with tunable thickness and atomic density. The cooperative Lamb shift arises due to the exchange of virtual photons between identical atoms. The interference between the forward and backward propagating virtual fields is confirmed by the thickness dependence of the shift which has a spatial frequency equal to $2k$, i.e. twice that of the optical field. The demonstration of cooperative interactions in an easily scalable system opens the door to a new domain for non-linear optics.