Abstract
This thesis describes experimental and theoretical work towards a novel dual species platform for Rydberg quantum information processing employing ultracold samples of potassium (K) and rubidium (Rb) atoms. The dual-species setup combined with the possibility of deploying arrays of ultracold atomic ensembles trapped in optical tweezers will pave the way for a new generation of Rydberg single-photon optical transistors with high input photon rate. Firstly, by using degenerate fermionic 40K samples as the storage medium one can take advantage of the Pauli exclusion principle which offers protection against loss and dephasing mechanisms of Rydberg polaritons, while the bosonic 87Rb species can be used as a benchmark. Secondly, simultaneously trapping nearby ensembles of the two species opens up the possibility of creating strong interactions between photons of different ”colours”, as well as the independent control of parameters of the atomic storage medium.
A theoretical study conducted in the first part of this thesis reveals multiple experimentally accessible pair combinations of K and Rb atoms in their respective Rydberg states which have high interaction strength. These K-Rb pair states offer long-range interaction suitable for such a spatially isolated transistor setup. The subsequent part presents experimental work towards a dual species Rydberg optical transistor. This includes the establishment of a laser system to access Rydberg states in both species, and a feedback system to reduce atom number fluctuations. Lastly, non-destructive measurements of Rydberg states, using electromagnetically induced transparency and the newly established setup, are presented for ultracold samples of 40K and 87Rb.