A Two-Species Magneto-Optical Trap Using 39K and 133Cs

Abstract

There is great interest in the use of ultracold polar molecules confined in op- tical lattices for quantum simulation of complex many-body problems. The objective of our work is to realise a system of ultracold fermionic 40K133Cs molecules in a 1D optical lattice consisting of an array of 2D pancake traps. Such a system will enable a wide range of future investigations, including the study of novel regimes of interlayer superfluidity [1]. To create polar molecules we will employ magnetoassociation on an interspecies Feshbach resonance followed by transfer to the rovibrational ground state using STIm- ulated Raman Adiabatic Passage (STIRAP). This thesis reports the progress towards this ambitious goal focusing on the initial laser cooling stage.
We present a simple single cell vacuum system that can be used to locate the interspecies Feshbach resonances essential for magnetoassociation. We give a description of the laser setups for both species, including details of the laser spectroscopy used for frequency stabilisation. We then present results on the optimisation of the magneto optical trap (MOT) for each species (focusing on the most abundant 39K isotope). The effects of the intensities and detun- ings of both the cooling and repump light and the magnetic field gradient are investigated in order to maximise the number of trapped atoms. Finally, we present preliminary observations of simultaneously loading overlapped MOTs for both species.