Three level atom spectrum in metal film between InP1−xSbxInP1−xSbx alloys

The spontaneous spectrum of a V  -type three level atom is studied inside a metal film between two semi-infinite alloys of InP1−xSbxInP1−xSbx. The surface plasmon polaritons dispersions supported by this structure are calculated as function of the stochiometric coefficient x. The spectrum function is shown to exhibit Fano type behavior when varied with x, suggesting that this parameter might play the role of Fano q-parameter in atomic physics.