We show that the quantum interference between two spontaneous emission channels can be greatly enhanced when a three-level $V$-type atom is placed near plasmonic nanostructures such as metallic slabs, nanospheres, or periodic arrays of metal-coated spheres. The spontaneous emission rate is calculated by a rigorous first-principles electromagnetic Green’s tensor technique. The enhancement of quantum interference is attributed to the strong dependence of the spontaneous emission rate on the orientation of an atomic dipole relative to the surface of the nanostructure at the excitation frequencies of surface plasmons.

• Received 5 February 2009

DOI:https://doi.org/10.1103/PhysRevLett.103.063602