Observation of the Mollow Triplet from an optically confined single atom

TL;DR

This paper reports the observation of the Mollow triplet in resonance fluorescence from a single optically trapped rubidium atom, demonstrating quantum correlations and photon emission dynamics useful for quantum information applications.

Contribution

First observation of the Mollow triplet in fluorescence from a single trapped atom with detailed photon correlation analysis and off-resonant excitation effects.

Findings

Detection of the Mollow triplet in a single atom fluorescence.

Observation of Rabi oscillations in photon correlations.

Asymmetry in photon correlations from sidebands under off-resonant excitation.

Abstract

Resonance fluorescence from atomic systems consists of a single spectral peak that evolves into a Mollow triplet for a strong excitation field. Photons from different peaks of the triplet show distinct photon correlation that make the fluorescence a useful light source for quantum information purpose. We characterize the fluorescence of a single optically trapped $^{87}$Rb atom that is excited resonantly at different power levels. Second-order correlation measurements reveal the single photon nature of the fluorescence concurrently with Rabi oscillations of a strongly excited atom. The asymmetry in correlations between photons from two sidebands of the fluorescence spectrum when the atom is exposed to an off-resonant field further indicates that there is a preferred time-ordering of the emitted photons from different sidebands.