This project is a study of the dynamics and spectra of optically driven atoms in the case that they are exposed to a perturbed electromagnetic mode density. It involves the design and construction of cavities whose perturbation of the electromagnetic mode density is particularly strong. Optical trapping techniques will be employed to eliminate transit-time limitations on the size of optical cavities or their active regions. Owing to the fundamental changes in driven atom dynamics that can occur in the presence of a perturbed electromagnetic mode density, the present studies may lead to the operation of optical devices in hitherto unaccessible regimes. A secondary objective of this work will be to investigate the response of free-space atoms to complex, for example bichromatic, excitation fields.