Excitation Dynamics of an Atomic Ensemble Located in a Waveguide

We study the dynamics of atomic excitation pre-pared in a dense ensemble located in a waveguide. We have shown that spontaneous decay can be incomplete, so the time dependence of the excited state population asymptotically approaches to a nonzero value, under the conditions when the atomic transition frequency is larger than the cutoff frequency of a waveguide and far from the vicinities of the cut-offs.