Rydberg Excitation and Other Multiphoton Processes in Cold Rubidium Atoms Near an Optical Nanofibre

S R Krishnapriya, Tridib Ray, Síle Nic Chormaic

Síle Nic Chormaic

In recent years, optical nanofibres have become a promising platform for trapping, manipulating and controlling atomic systems. In this work, I will highlight our recent work on the demonstration of multiphoton processes using optical nanofibres embedded in a Rb MOT for the generation of entangled photons and the excitation of Rydberg atoms for all-fibred quantum networks.

Jeonghun Lee, Javed Iqbal, Tom Gallagher

Vandna Gokhroo, Fam Le Kien, Síle Nic Chormaic

Abstract The integration of cold atomic systems with optical nanofibres (ONFs) is an increasingly important experimental platform. Here, we report on the spectra observed during a strongly driven, single-frequency, two-photon excitation of cold rubidium atoms near an ONF. At resonance, two competitive processes, namely a higher excitation rate and stronger pushing of atoms from the nanofibre due to resonance scattering, need to be considered. We discuss the processes that lead to the observed two-peak profile in the fluorescence spectrum as the excitation laser is scanned across the resonance, noting that the presence of the ONF dramatically changes the fluorescence signal. These observations are useful for experiments where high electric field intensities near an ONF are needed, for example when driving nonlinear processes.

Anna Kortel, Sergei Abdrakhmanov, Anton Konovalov +4 more

Photonics platforms combining laser-cooled atoms with optical nanofibres facilitate strong light–matter interactions across the classical and quantum regimes. The subwavelength confinement of the fibre-guided modes produces a large evanescent field, allowing efficient coupling of light to nearby atoms. We investigate atom-mediated processes in nanofibre-based platforms, with particular focus on Rydberg excitation of cold 87 Rb in close proximity to a dielectric. We identify key limitations to excitation efficiency and discuss alternative trapping strategies to overcome these effects.

Thibault Peyronel, Ofer Firstenberg, Qiyu Liang +1 more