"Boson gases confined in lattices present fundamental properties which strongly depart from their 3D counterparts. A notorious example is the honeycomb lattice, whose geometry results in massless Dirac-like states. By engineering the phase picked by the particles when tunneling from site to site, lattices also allow for the generation of artificial gauge fields. They result in very strong effective magnetic fields, opening the way to the observation of new quantum Hall regimes in neutral particles. In this context, polaritons appear as an excellent platform for the study of boson fluid effects in confined geometries. Polaritons are two-dimensional half-light/half-matter quasi-particles arising from the strong coupling between quantum well excitons and photons confined in a semiconductor microcavity. They are fully accessible by optical means and present strong non-linear properties. In this project, I will fabricate polariton microsstructures to study mesoscopic physics in 2D lattics.I will start by studying the non-linear Josephson dynamics in coupled micropillars, and engineer a double tunneling structure showing single polariton blockade. I will then fabricate a graphene-like honeycomb lattice, where I will study transport phenomena such as anomalous (Klein) tunneling and antilocalisation in the presence of disorder, phenomena originating from the Dirac-cone characteristic of honeycomb lattices. In the high density regime, I will investigate non-linear effects, and address the question of superfluidity of massless Dirac particles.Finally, I will undertake the realization of artificial gauge fields for polaritons. I will adapt to the polariton case a recent theoretical proposal to create artificial gauges in photons using coupled microdisks. Our results will have strong impact on current studies on the transport properties of graphene, of boson gases in atomic condensates, and also on the design of photonic systems with topological protection from disorder."