| This thesis presents theoretical derivations and experimental demonstrations of Kerr optical nonlinearities and their dynamics. The Kerr nonlinearity studied is based on electromagnetically induced transparency (EIT), and is known for having an unusually large cross-phase modulation (XPM) [1]. Also, quantum nondemolition (QND) measurements of photon number using the EIT Kerr nonlinearity are discussed.; We first discuss the EIT line shapes in hot atomic vapors both with and without buffer gasses, and for the specific case of EIT line shapes on the. D1 line of rubidium. Using a Bloch-vector formalism to describe EIT, we derive new expressions describing the dynamical evolution of the EIT Kerr nonlinearity and the rise-time of the EIT Kerr effect.; The theory of the EIT Kerr dynamics is confirmed by experiments using hot rubidium vapor in a buffer gas. These experimental observations confirm that the rise-time of the EIT Kerr effect is linearly proportional to the optical thickness of the EIT medium and inversely proportional to the width of the EIT transparency resonance.; We find that the EIT Kerr effect is relatively slow, and that its rise-time is inversely proportional to the EIT Kerr susceptibility. The implications of the slow rise-time to QND measurements is investigated, and it is found that by matching the group velocities of the probe and signal optical fields, the signal to noise ratio for QND measurements is improved. Predictions for the EIT Kerr dynamics with slow group velocity for the signal field were confirmed experimentally in rubidium vapor with group velocities of about 10 4 m/s for both probe and signal optical fields. |
