Polaritons are matter-light hybrid quasi-particles, formed by coherent energy exchange between matter excitations and the optical field.  Semiconductor exciton-polaritons, in particular, integrate strong optical nonlinearities and spontaneous coherence into a semiconductor photonic platform. Ripe with potential for new many-body physics phenomena, such as spontaneous spin polarization and non-equilibrium superfluidity, they also promise new photonic technologies. Lasing without population inversion, terahertz optical switching and polariton interferometers have all been demonstrated in GaAs systems, albeit at <20 K. Accessing a broader range of quantum phenomena at higher temperatures requires much stronger exciton-photon coupling and greater control over system properties.

Recently, optically active van der Waals crystals (vdWCs) such as transition-metal dichalcogenides promise extraordinary exciton-photon coupling strengths, allow unprecedented flexibility for integration of different vdWCs and other solids, and feature many unique properties for novel phenomena, such as the coupled spin and valley degrees of freedom, strong phonon-charge interactions, and stable multi-charge cluster excitations. Exploiting these properties, the goal of the Multidisciplinary University Research Initiative is to establish a versatile room temperature 2D vdWC polariton system as a bridge from the discovery of new manybody phenomena to novel photonic technologies – the polaritronics. We aim to:

  1. Create room temperature 2D vdWC-polariton system suitable for quantum manybody phenomena.
  2. Control the properties of 2D vdWC-polaritons to unravel new phenomena.
  3. Demonstrate and utilize room temperature polariton condensate and superfluidity for new types of emitters, detectors, and routers.

We will pursue these goals via a collaborative, multidisciplinary effort, combining state-of-the-art fabrication capabilities with strong experimental and theoretical expertise on four core aspects of the project: polariton physics, 2D materials, photonic devices, and many-body physics in photonic and electronic systems.