Experimental demonstration of plasmonic quantum walks in the one-dimensional gold-strip waveguide lattice structure


  Shuichiro Inoue, Nihon University

Quantum walks (QWs) simulate quantum mechanical behaviours of particles, which exhibit time evolutions completely different from the classical random walks. QWs offer quantum physical simulations and the novel approach to build quantum computers. Currently on-chip photonic devices have been intensively developed and QWs have been implemented using photonic circuits based on silica waveguide platforms.

We have experimentally demonstrated QWs in one-dimensional lattice structures based on the long-range surface plasmon polariton (LR-SPP) waveguide platform. The LR-SPP waveguide allows a single-polarization mode, and has relatively low optical losses. The plasmonic quantum interference can be realized in a LR-SPP waveguide circuit with a high visibility as well. Furthermore, the LR-SPP waveguide platform will realize two-dimensional waveguide lattice structures with a high reliability. Thus, the LR-SPP waveguide is the potential platform to construct large-scale and high-dimension QW simulators.

The figure shows the one-dimensional LR-SPP waveguide lattice structure. The LR-SPPs were excited via batt connection between the single-mode fiber and the centre waveguide of 51-arrayed ones. We successfully observed the intensity distribution which exhibits the one-dimensional symmetry continuous QW.