Atomic dipole squeezing in the degenerate a quantum beat three-level system

By using the full quantum theory, we investigate the time evolution of the atomic dipole squeezing parameters of a A-type three-level atom interacting with a single-mode coherent optical field, and study the influence of the initial coherent-field intensity, the initial atomic coherence, the initial populations and energy splitting of the two lower atomic levels on the atomic dipole squeezing. The influence of a classical external driving field coupling to the atom on the atomic dipole squeezing is also explored at the end of the paper.