Spontaneous decay rate and Casimir-Polder potential of an atom near a lithographed surface

TL;DR

This paper develops a method to calculate radiative corrections for an atom near complex surface features, revealing new behaviors in decay rates and Casimir-Polder potentials due to surface perturbations.

Contribution

It introduces a Green's function approach for arbitrarily-shaped surface depositions, enabling analysis of atomic decay and Casimir-Polder effects near complex surfaces.

Findings

Decay rate and Casimir-Polder potential are affected by surface features.

Periodic behavior of Casimir-Polder potential persists beyond immediate vicinity.

New qualitative behaviors observed in atom-surface interactions.

Abstract

Radiative corrections to an atom are calculated near a half-space that has arbitrarily-shaped small depositions upon its surface. The method is based on calculation of the classical Green's function of the macroscopic Maxwell equations near an arbitrarily perturbed half-space using a Born series expansion about the bare half-space Green's function. The formalism of macroscopic quantum electrodynamics is used to carry this over into the quantum picture. The broad utility of the calculated Green's function is demonstrated by using it to calculate two quantities --- the spontaneous decay rate of an atom near a sharp surface feature, and the Casimir-Polder potential of a finite grating deposited on a substrate. Qualitatively new behaviour is found in both cases, most notably in the latter where it is observed that the periodicity of the Casimir-Polder potential persists even outside the immediate vicinity of the grating.