2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/89328The influence of a microsphere having a simultaneously negative permittivity and permeability (Left-Handed Sphere) on the decay rate of the allowed and forbidden transitions is considered. It is found, that in contrast to usual (Right-Handed) materials it is possible to increase the decay rate by several orders of magnitude even in the case of a sphere of small radii. This enhancement is due to the fact that there exist a new type of resonance modes (LH surface modes). The analytical expressions for resonance frequencies and associated quality factors of the new modes are found.8 pages, 6 figures, minor grammatical changesQuantum Physicstext