Variation of the emission characteristics of an atom located near an ideally conducting conical surface

The line width and the emission frequency of an atom located near the vertex of an ideally conducting cone or inside a conical cavity in an ideal conductor are analysed. It is shown that the influence of the vertex diminishes with decrease in the vertex angle. On the other hand, the line width and the emission frequency of an atom located in a conical cavity may both increase and decrease greatly, depending on the position of the atom and on the vertex angle of the cavity. The results obtained may prove useful in the development of both monatomic microlasers and spectrally selective near-field nanoscopes.