Coherent manipulation of single atom qubits using Rydberg states

This thesis presents experimental observations of the coherent manipulations of Rubidium-87 atoms via two photon excitations. Atoms are cooled using a magneto-optical trap (MOT) into two far off resonance traps (FORT) that are separated by 10 micrometers. State sensitive single atom detection is performed by gathering the fluorescence signal of two atoms trapped in the FORT potentials with an electron-multiplying CCD camera. A custom built multiplexing optical system is used to individually address the FORT potentials. A microwave modulated 780nm laser is used to coherently Rabi flop atoms between the F=1 and F=2 hyperfine ground states via two photon excitations. Cavity stabilized lasers at 780nm and 480nm are used to conduct two photon excitations of F=2 hyperfine ground state atoms to Rydberg states with principal quantum numbers ranging from n=43 to n=97.;This experiment is the first to observe coherent Rabi oscillations at megahertz rates between ground and Rydberg levels. These coherent Rydberg Rabi oscillations are used to demonstrate Rydberg blockade at a single atom level for the first time. The Rydberg Rabi oscillations of a target atom are observed to be 75% blockaded by the presence of a Rydberg atom more than 10 micrometers away. This paper reports on the preliminary work towards the first neutral atom controlled-NOT (CNOT) gate, and on preliminary experiments working towards deterministic loading of single atoms in a FORT potential.