Smalltalks "Exploring aluminium nitride for optomechanics"

Abstract: 

To isolate its motion from disturbance from the environment, a resonator must have an ultrahigh mechanical quality factor, Q, and high mechanical frequency, f. By taking advantage of strain engineering, quality factors up to 10 billion can be reached in crystalline silicon resonators. Crystalline materials provide lower density of defects, enabling higher mechanical quality factors and new functionality compared to amourphous materials. A wide bandgap aluminium nitride grown on silicon has a high lattice mismatch providing a high quality mechanical factor and relatively high piezoelectricity coefficient. We demonstrate resonator designs with ultrahigh mechanical quality factors and reach Qf products above 10¹². These are the first ultrahigh-Q resonators that feature piezoelectricity and we expect that they can be used in quantum optomechanical systems.