Metrology of microwave fields based on trap-loss spectroscopy with cold Rydberg atoms

TL;DR

This paper introduces a simple, highly accurate method for microwave field measurement using trap-loss spectroscopy of cold Rydberg atoms, offering advantages over traditional vapor-based sensors.

Contribution

The authors present a novel microwave metrology technique employing cold Rydberg atoms and fluorescence detection, enabling simultaneous amplitude and frequency measurement without external references.

Findings

Achieved percent-level linearity in scale factor

Demonstrated stability with no noticeable drifts over two hours

Validated the method's potential for various advanced applications

Abstract

We demonstrate a new approach for the metrology of microwave fields based on the trap-loss-spectroscopy of cold Rydberg atoms in a magneto-optical trap. Compared to state-of-the-art sensors using room-temperature vapors, cold atoms allow longer interaction times, better isolation from the environment and a reduced Doppler effect. Our approach is particularly simple as the detection relies on fluorescence measurements only. Moreover, our signal is well described by a two-level model across a broad measurement range, allowing in principle to reconstruct the amplitude and the frequency of the microwave field simultaneously without the need for an external reference field. We report on a scale factor linearity at the percent level and no noticeable drifts over two hours, paving the way for new applications of cold Rydberg atoms in metrology such as calibrating blackbody shifts in state-of-the-art optical clocks, monitoring the Earth cryosphere from space, measuring the cosmic microwave background or searching for dark matter.