Intrinsic Optical Bistability in Collections of Spacially Distributed Two-Level Atoms

摘要

A quantum electrodynamical, many body treatment is used to show mirrorless optical bistability in terms of the spatial properties of coherent dipole dipole interactions among interacting two-level atoms. The general theory is applied to two special cases: (1) a thin sample of two-level atoms, with a width smaller than a resonance wavelength, and (2) a long sample of two atoms with dimensions very large relative to a resonance wavelength. While for the thin sample we are able to use a mean-field approximation with validity, for the long sample we are compelled to take into account retardation and propagation. In both cases bistability is found to be related to a renormalization of the frequency (or relaxation rate) that is inversion-dependent. For the long sample the frequency renormalization is significant for high atomic densities and for large oscillator strengths.