Surface Plasmon Polaritons: Excitation and effect of loss in the quantum regime

The possibility to use noble metals to guide light could lead to truly nanoscale photonic devices. Surface Plasmon Polaritons (SPPs), charge density waves of electrons at the interface between a metal and a dielectric, can be excited by light, and guide it with a deep sub-wavelength confinement. Another exciting prospect is their use in nanoscale quantum optics experiments: it has been shown that some of the quantized properties of the field used to excite them are maintained through the conversion to SPPs [1]. Yet, much is to be understood of the SPPs properties before being able to produce working devices. We will present our most recent works on SPPs. First we will discuss the possibility to use nanoslits in a metal film as very compact, directional light-SPPs couplers. We will see that there is a trade-off between the coupling efficiency and how compact this system can be [2]. Then, we will discuss the influence of SPP propagation loss on the quantum properties single SPPs, excited by single photons, focussing on the number state degree of freedom. Our findings are consistent with a linear uncorrelated environment, even in the quantum regime [3].