Transmission of surface plasmon polaritons through atomic-size constrictions.

We study the excitation and propagation of surface plasmon polaritons (SPPs) on a micron-sized thin gold stripe. Grating couplers are embedded for both excitation of SPPs and detection after propagation. The experimental setup allows measuring of the decay length of the SPPs on the gold stripe excited in the near infrared part of the electromagnetic spectrum. We show that SPPs are transmitted with a surprisingly high probability across a tapered constriction, with smallest lateral dimensions of atomic size. [ABSTRACT FROM AUTHOR]