Bright and dark Autler-Townes states in the atomic Rydberg multilevel spectroscopy

TL;DR

This paper analyzes the Autler-Townes splitting in Rydberg atoms using optical spectroscopy and the Morris-Shore transformation, revealing bright, dark, and spectator states and complex spectra under strong microwave dressing.

Contribution

It introduces a theoretical framework applying the Morris-Shore transformation to multilevel Rydberg systems, identifying different state configurations and synthetic spectra.

Findings

Identification of bright, dark, and spectator states in Rydberg spectra

Derivation of synthetic spectra capturing main spectral features

Observation of complex Autler-Townes spectra under strong microwave dressing

Abstract

We investigated the Autler-Townes splitting produced by microwave transitions between atomic Rydberg states explored by optical spectroscopy from the ground electronic state. The laser-atom Hamiltonian describing the double irradiation of such a multilevel system is analysed on the basis of the Morris-Shore transformation. The application of this transformation to the microwave-dressed atomic system allows the identification of bright, dark, and spectator states associated with different configurations of atomic states and microwave polarisation. We derived synthetic spectra that show the main features of Rydberg spectroscopy. Complex Autler-Townes spectra are obtained in a regime of strong microwave dressing, where a hybridisation of the Rydberg fine structure states is produced by the driving.