Single barium ion spectroscopy: Light shifts, hyperfine structure, and progress on an optical frequency standard and atomic parity violation

Single trapped ions are ideal systems in which to test atomic physics at high precision: they are effectively isolated atoms held at rest and largely free from perturbing interactions. This thesis describes several projects developed to study the structure of singly-ionized barium and more fundamental physics.; First, we describe a spin-dependent 'electron-shelving' scheme that allows us to perform single ion electron spin resonance experiments in both the ground 6S1/2 and metastable 5D 3/2 states at precision levels of 10-5. We employ this technique to measure the ratio of off resonant light shifts (or ac-Stark effect) in these states to a precision of 10-3 at two different wavelengths. These results constitute a new high precision test of heavy-atom atomic theory. Such experimental tests in Ba+ are in high demand since knowledge of key dipole matrix elements is currently limited to about 5%. Ba + has recently been the subject of theoretical interest towards a test of atomic parity violation for which knowledge of dipole matrix elements is an important prerequisite. We summarize this parity violation experimental concept and describe new ideas.; During the study of the nuclear spinless (I = 0) isotope of Ba+, we discovered several worthwhile experimental goals for an isotope with nuclear spin, 137Ba+ ( I = 3/2). The hyperfine structure of the metastable 5D 3/2 state is currently known to a precision 10-4. We show how our rf spin-flip spectroscopy scheme could measure this structure to parts in 10-8 or better, allowing a determination of the nuclear magnetic dipole, electric quadrupole, and perhaps magnetic octopole moments.; Finally, the hyperfine structure of 137Ba+ yields an optical transition with unique advantages in a single ion optical frequency reference. Namely, the 2051 nm 6S1/2, F = 2 ↔ 5D3/2, F' = 0 transition is effectively free of quadrupole (or gradient) Stark shifts which may plague competing ion frequency references at the 10 -16 level. We describe the performance and frequency narrowing of a diode-pumped solid state 2051 nm laser, and the observation of transitions in Ba+. We also estimate all known systematic effects on this transition and conclude that the realization of a frequency standard with long-term precision of < 10-17 is possible at cryogenic temperatures.