Polaritons are quantum superpositions of light and matter which combine appealing properties of both: the high coherence of photons and the strong interaction (non-linearities) of electrons. With the report of their Bose-Einstein condensation in 2006, they stand as one of the most exciting semiconductor-optical system of today. Given their peculiar character, they encompass different interdisciplinary areas of research which spans from the physics of phase transitions, critical phenomena and strongly-correlated systems (superfuidity, superconductivity, etc.) to various branches of quantum physics (quantum optics, quantum information, etc.), till the possibility of building polariton-based optical logics for implementation of optical circuits; all exciting realms yet to be explored.The majority of the outstanding findings reported have been realised in structureless samples with no, or random, potential barriers for polariton states. This proposal aims at developing the polariton physics in the presence of designed and controllable potential landscapes which will allow the observation and study of a new series of phenomena related to the system's reduced dimensionality and out-of-equilibrium character.Strong of several and complementary techniques to realize such potentials in microcavities, both in my institute and in partnership with leading growers worldwide, I will explore three phases of prospective physics in the framework where the polariton flow can be controlled, driven, localised and guided. First, I will study transport and interferometry. Then, these straightforward upgrades on the polariton state-of-the-art will be used to design elementary devices, such as polariton transistors (classical logic) or entangling devices (quantum logic). In a final phase, polariton lattices with controllable attributes will be used to study fundamental quantum phases from the superfluid to the Mott insulator, with prospects of realizing a polariton quantum simulator.