UC Berkeley

The technique of laser cooling, and its application in the generation of ultracold gases of atoms, has reshaped AMO physics and related fields such as quantum many-body physics, precision metrology and quantum information science. However, only a fraction of the atoms in the periodic table have been laser cooled, and by realizing ultracold gases of different classes of elements, new phenomena can be explored. This work describes the laser cooling of neutral titanium (Ti) atoms, beginning with the theoretical proposal and ending with the implementation of the first magneto-optical trap (MOT) of Ti atoms.After describing how laser cooling proceeds in previously laser cooled atoms, the atomic structure of neutral Ti is examined to determine how laser cooling can be achieved with minimal experimental complexity. The proposed Ti laser cooling scheme is extended to twelve other transition metal elements that had not previously been considered as candidates for laser cooling, building on our previously published work. Calculations of the interaction between Ti atoms and light allow me to model the expected behavior of the atoms in a MOT as well as to propose future experimental directions in precision metrology and quantum many body physics with Ti atoms.I present details of our experiments with Ti, starting with spectroscopy and atomic beam generation before proceeding to the description of the 3d MOT experimental system. Observations from the MOT show that, as predicted by my previous calculations, Ti has favorableproperties for laser cooling, with low loss rates to atomic dark states or inelastic light-induced collisions. In the simple experimental apparatus, the atoms are brought to temperatures below 100 μK and densities above 1 × 1011 atoms/cm3. Additionally, the presence of a narrow-linewidth atomic transition enables the implementation of a second stage MOT to further cool the Ti atoms to below 20 μK while also spin-polarizing the gas, providing an ideal starting point for future experiments with ultracold Ti.