Normal-Mode Line Shapes for Atoms in Standing-Wave Optical Resonators

Abstract

A high finesse standing-wave cavity mode resonantly interacting with a beam of two-level ${}^{138}\mathrm{Ba}$ atoms is weakly driven by a tunable laser. Transmitted and sidelight scattered line shapes are recorded. With mean intracavity atomic number, $〈\overline{N}〉\approx 1$, we observe one-, two-, and three-peaked line shapes for strong coupling. In addition, two-peaked spectra observed in intermediate coupling demonstrate that line-shape splitting is not necessarily indicative of oscillatory atom-cavity energy exchange. Several atoms are required for $〈\overline{N}〉\approx 1$, so this is not a true single-atom regime.