We consider the two-dimensional (2-D) problem of the H-polarized electromagnetic eigenmodes that can exist on a silver nanostrip placed in the centre of an active shell in the form of circular quantum wire (QW).
Both the lasing mode frequency and the associated threshold value of material gain in QW are extracted from the lasing eigenvalue problem (LEP). It is found that the nanostrip-based laser can emit visible light on several localized surface plasmon (LSP) modes and also on the “shell modes” or QW polariton modes perturbed by the strip.