Abstract

Investigations of the radiative processes for the composite system of N two-state atoms coupled to the field of a high finesse optical cavity are reported. In an experiment employing an atomic beam of optically prepared sodium atoms (3S_1/2, F = 2, m_F = 2 → 3P_3/2, F = 3, m_F = 3 transition at 589 nm), we make direct spectroscopic measurements of the normal mode splitting for the coupled oscillator system of atoms and cavity field over a 20 ≤ N ≤ 600 range. Linewidth reduction below the atomic free-space width is observed and results from dynamic linewidth averaging due to the strong coherent interaction of atoms and cavity. The dependence of the normalmode structure on atom-cavity detuning is explored, and the decoupling of the system with detuning is described. A second experimental program employs a cesium atomic beam (6S_1/2, F = 4, m_F = 4 → 6P_3/2, F = 5, m_F = 5 transition at 852 nm), for which the single-atom coupling coefficient can be made larger than the free-space atomic and cavity damping rates. Our initial efforts are directed both toward the investigation of the spectroscopic properties of this system and toward the observation of photon antibunching for the field transmitted from the cavity. More generally our measurements of intensity correlations can be applied to the problem of continuous quantum measurement for a dissipative system.

© 1989 Optical Society of America