Physical review. B./Physical review. B
Generating N00N states of surface plasmon polaritons with N = 2 by a single nanoparticle
Nikita A. Olekhno, Mihail I. Petrov, Ivan V. Iorsh, Andrey A. Sukhorukov, Alexander S. Solntsev
Abstract
We consider a generation of two-particle quantum states in the process of spontaneous parametric down-conversion of light by a dielectric nanoparticle with a bulk ${\ensuremath{\chi}}^{(2)}$ response. As a particular example, we study the generation of surface plasmon polariton pairs with a $\mathrm{GaAs}$ nanoparticle located at the silver-air interface. We demonstrate theoretically that $\mathrm{N}00\mathrm{N}$ states of surface plasmon polariton pairs with $N=2$ can be obtained for certain excitation geometries. The effect can be physically interpreted as the result of a quantum interference between the pairs of induced sources, each emitting either signal or idler plasmons. We then relate the resulting $\mathrm{N}00\mathrm{N}$ pattern to the general symmetry properties of a dyadic Green's function of a dipole emitter exciting surface waves. It renders the considered effect as a general way towards the robust generation of $\mathrm{N}00\mathrm{N}$ states of surface waves using spontaneous parametric down-conversion in ${\ensuremath{\chi}}^{(2)}$ nanoparticles.