Ultrahigh quality van der Waals hyperbolic polariton resonators

We demonstrate the growth, assembly, and characterization of ultrahigh quality polaritonic systems based on α-MoO3 microplates and nanoribbons. These micro- and nanostructures are bottom-up-synthesized single crystals with minimal impurities. By optimizing the growth conditions, we also realize morphology control of the α-MoO3 structures. We observe highly confined polariton modes in the individual structures by using scattering-type scanning near-field optical microscopy. These highly confined polariton modes are of fundamental and technological interest.