Spontaneous emission of an excited atom placed near a left-handed sphere

The electrodynamical properties of a microsphere made of hypothetical material with a simultaneously negative permittivity and permeability (a left-handed (LH) sphere) are considered. It is shown that three types of resonance modes can be excited in such a sphere: the whispering gallery modes, the plasmon oscillations and the new LH surface modes, which have an anomalous behaviour of the resonant curves. The analytical solution of the dispersion equation is found. It is demonstrated that the electric (E1) and magnetic (M1) dipole decay rates of an atom placed near such left-handed sphere suffer a substantial enhancement in the case of resonance with the modes of a sphere. (C) 2002 Elsevier Science B.V. All rights reserved.