Radiative decay engineering by triaxial nanoellipsoids

Radiative decay rate of an atom placed near a triaxial nanoellipsoid is investigated. Analytical results are obtained for a general case. It is shown that a triaxial ellipsoid can be used for an efficient control of the decay rate of an atom, molecule or quantum dot and for high-efficiency coupling of the far field radiation to the near-field domain. For example, the decay rate near a silver ellipsoid can be enhanced by five orders of magnitude. It is also shown, that a triaxial nanoellipsoid can be used for simultaneous efficient control of absorption and emission rates of fluorophores.