Characterisation and quantum application of plasmonic waveguides.

Abstract

Plasmonics o ers sub-di raction confinement of light, which a ords enhanced coupling to emitter systems (e.g. quantum dots). This feature makes possible a range of on-chip quantum photonic components - most notably single-photon sources and switches. This potential use of plasmonics, along with the nonlinearity provided by emitter systems, opens up quantum plasmonics as a viable route to realising quantum information processing. In this setting, the excitation of single surface plasmon polaritons (SPPs) on waveguides via single photons and the confirmation of single-photon states upon output is an important goal. In the work reported here, plasmonic waveguides were experimentally probed with single photons. A measurement of the secondorder quantum coherence function yielded a value of g(2)(0) = 0:160 0:002. A value less than 0.5 is indicative of single-excitation states. Furthermore, to confirm successful SPP excitation, the transverse-magnetic mode restriction and exponential decay of SPPs were verified. Having firmly established the ability to probe plasmonic waveguides in the classical and quantum regimes, quantum random number generation was implemented using a plasmonic beam splitter. The random bit sequences produced passed the NIST Statisitical Test Suite once post-processed to correct for a slightly asymmetric beamsplitter.