In this thesis, we present our methods and results towards the development of deterministic preparation of single neutral atoms with a known quantum state in a single trap potential. Firstly, we experimentally study the dynamics of two atoms that undergo light-assisted collisions, where we can quantify different two-atom loss channels. We find that a combination of repulsive light-assisted collisions and in-trap laser cooling can result in only one of the two colliding atoms escaping the trap with near unity probability. This forms the essential basis in our single atom preparation method. With optimized repulsive light-assisted collisions and laser cooling parameters, we can prepare single neutral atoms with a preparation efficiency of 91%. When similar methods are applied in collisional blockade loading of single atoms in a tight trap, the preparation efficiency can be enhanced from the previously observed limit of around 50% to 80%. In a separate experiment, we also demonstrate an in-trap fluorescence detection method to count the number of atoms in a high density trap from 1 to more than 100 atoms with sub-Poissonian precision. Finally, we perform Raman sideband cooling on the prepared single atom with a single pair of Raman transition beams that couples both of the radial vibrational dimensions of the trapped atom. We show that the atom occupies the vibrational ground state in the two radial dimensions with a probability of 84%. This gives a 69%fidelity for the preparation of a pure atomic quantum state for a 2-D system.
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Near-deterministic preparation of single atoms and Raman sideband cooling
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