Precise, super-resolving intensity measurement by quantum jump spectroscopy of a single neutral atom

TL;DR

This paper introduces a highly precise method for measuring optical intensity at sub-wavelength scales using quantum jump spectroscopy on a single atom, significantly reducing systematic errors and enabling super-resolution measurements.

Contribution

The authors develop a novel quantum jump spectroscopy technique that enhances measurement precision and reduces systematic effects in atomic-scale optical intensity sensing.

Findings

Achieved sub-wavelength optical intensity measurement with high accuracy.

Demonstrated the method by measuring intensity at an optical tweezer focus.

Reduced systematic errors compared to traditional measurement techniques.

Abstract

We present precise, sub-wavelength optical intensity measurement using a single trapped $^{87}$Rb atom as a sensor. The intensity is measured by the scalar ac Stark shift it produces on the $F=1 \rightarrow F'=2$ hyperfine transition of the D$_{2}$ line, chosen for its $F' = F+1$ structure and very small tensor polarizability. To boost signal and reduce measurement-induced perturbations, we use a quantum jump spectroscopy technique in which a single absorbed photon on a transition of interest induces the scattering of hundreds of photons on a bright closed transition. The method greatly reduces systematic effects associated with the atomic state, optical polarization, probe power, and atom heating, and gives the atomic temperature as a second spectroscopic observable. We demonstrate the method by measuring the intensity at the focus of an optical tweezer.