Brillouin-Wigner perturbation theory in open electromagnetic systems
School of Physics and Astronomy, Cardiff University - The Parade, CF24 3AA, Cardiff, UK, EU
2 Institut für Physik der Humboldt- Universität zu Berlin - Newtonstrasse 15, D-12489 Berlin, Germany, EU
Accepted: 21 November 2010
A Brillouin-Wigner perturbation theory is developed for open electromagnetic systems which are characterised by discrete resonant states with complex eigenenergies. Since these states are exponentially growing at large distances, a modified normalisation is introduced that allows a simple spectral representation of the Green's function. The perturbed modes are found by solving a linear eigenvalue problem in matrix form. The method is illustrated on exactly solvable one- and three-dimensional examples being, respectively, a dielectric slab and a microsphere.
PACS: 03.50.De – Classical electromagnetism, Maxwell equations / 42.25.-p – Wave optics / 03.65.Nk – Scattering theory
© EPLA, 2010