Arno, Alberto

Date: Thursday March 27, 201
Time: 16:45
Place: ETH Zurich, Hönggerberg, HIT H 42
Host: Atac Imamoglu

Polariton condensates in photonic lattices

Alberto Amo
Laboratoire de Photonique et Nanostructures, CNRS, Marcoussi, France

Polaritons are mixed-light matter quasi-particles arising from the strong coupling between quantum well excitons and photons confined in a planar semiconductor microcavity. Thanks to their photonic part polaritons can be easily manipulated and detected using standard optical techniques, while their excitonic component results in strong polariton-polariton non-linearities. The potential landscape in which polaritons live can be engineered by locally deep etching the planar structure. In this way, one-dimensional wires and zero-dimensional micropillars have been fabricated.

By designing spatially overlapping micropillars, we can fabricate two dimensional lattices in which polaritons can hop from micropillar to micropillar. Here we will present the experimental realisation of a honeycomb lattice of micropillars showing several sets of bands [1]. The lowest energy ones mimic the dispersion of electrons in graphene, with linear crossings around six Dirac cones. At higher energy, the coupling between the p orbitals of individual micropillars gives rise to a flat band.

One of the attractive elements of this kind of structure is that by taking into account the polarization degree of freedom of polaritons, we can engineer an effective photonic spin-orbit coupling. We will show the first steps towards the implementation of a spin-orbit coupling acting on polaritons and speculate on its extension to two dimensional lattices.

The realization of structures which hold massless, massive and infinitely-massive particles in combination with spin-orbit coupling opens the route towards studies of the interplay of dispersion, interactions and frustration in a novel and controlled photonic environment.

[1] T. Jacqmin et al., Phys. Rev. Lett. 112, 116402 (2014)