At the frontier between non-linear optics and the physics of Bose Einstein condensation, semiconductor microcavities opened a new research field, both for fundamental studies of bosonic quantum fluids in a driven dissipative system, and for the development of new devices for all optical information processing.
Optical properties of semiconductor microcavities are governed by bosonic quasi-particles named cavity polaritons, which are light-matter mixed states. Cavity polaritons propagate like photons, but interact strongly with their environment via their matter component.
After a general introduction on cavity polaritons, I will review recent experimental works performed on polariton condensates confined in microstructures.
I will first show how we can generate, in one-dimensional cavities, polariton flows which propagate over macroscopic distances (mm), while preserving their spontaneous coherence. These propagation properties can be used to implement a variety of optically controlled polariton devices: the example of a non-linear resonant tunneling polariton diode will be addressed, a device very promising to reach the quantum regime of polariton blockade.
The last part of the talk will be devoted to the physics of polaritons in periodic potentials. I will discuss polariton condensation in a 1D periodic potential, the generation of spontaneous spin currents in the photonic analog of a Benzene molecule (a ring of six coupled micropillars), and finally the direct visualization of Dirac cones in a honeycomb lattice (the photonic analog of graphene).
These examples highlight the great potential of semiconductor cavities as a new platform to investigate the physics of interacting bosons.