Atomic spontaneous decay near a finite-length dielectric cylinder

• The spontaneous decay rate of an excited atom being located near a finite-length cylinder has been considered using a truncated Born expansion of the Green tensor.
• Limitations of the infinitely long cylinder model have been investigated.
• The range of applicability of the first-order Born expansion has been established.
• It has been shown that the spontaneous decay rate is modified most significantly around the edge of the cylinder.
• An estimation of the second-order term has been obtained.

Using a truncated Born expansion of the Green tensor, we consider the spontaneous decay rate of an excited two-level atom placed in the vicinity of a finite-length dielectric cylinder. It is shown that the spontaneous decay rate experiences most pronounced modifications in the edge regions. By comparing the results obtained for finite-length cylinders with those obtained for an infinitely extended one, we establish the parameters ranges where the latter is a valid approximation. We discuss how some typical singularities in the Born series, which arise when the integral variables coincide, can be removed.