Phononics at extremely high frequencies

Speaker: Hong Tang, Yale University

Mechanical resonators operating in the sub-terahertz (THz) regime could be of use in the development of future communication systems because they support extremely fast data rates. Such resonators are also of interest in studying quantum phenomena of mechanical entities, as they can maintain quantum ground state at Kelvin temperatures rather than the milli-Kelvin temperatures demanded by gigahertz (GHz) resonators. Here we report micro-electromechanical resonators operating beyond 100 GHz. By incorporating a millimeter-wave resonator into a thickness-shear mode micromechanical system, we achieve efficient electromechanical transduction through enhanced on-chip impedance matching, which is key to revealing the infinitesimal displacements of these sub-THz mechanical modes. Our devices are based on commercially available z-cut lithium niobate thin films and patterned using standard semiconductor fabrication processes.