Enhancement and inhibition of radiation in cylindrically symmetric, periodic structures

The effects of a two-dimensional, cylindrically symmetric periodic structure on the radiation from a source located inside the structure are considered. The coupling of the source radiation to the cylindrical cavity is analyzed classically by consideration of the interaction of a current line source with its own radiated field supported by the cavity. The analysis predicts variations in the radiative damping rate (inverse lifetime) and associated shifts in the oscillation frequency of the source. It is found that significant enhancement and inhibition of the radiation are possible even when the source is not at the center of the structure. Frequency shifts induced by the cavity are found to be negligible relative to the size of the band gap of the Bragg structure. The class of periodic structures analyzed has potential application to planar waveguide devices, such as concentric-circle gratings, surface-emitting lasers, and cylindrically symmetric lasers and amplifiers.