Shun Yanai, Delft University of Technology
Microwave optomechanical circuits have been demonstrated in the past years to be powerful tools for both, exploring fundamental physics of macroscopic and massive quantum objects as well as being promising candidates for novel on-chip quantum limited microwave devices. In this work, we explore a microwave optomechanical device consisting of a coplanar microwave cavity coupled to a mechanical high quality factor nanobeam resonator. By design, we have direct access to the mechanical subsystem, which allows for frequency tuning, coherent driving and parametric modulation of the nanobeam resonance frequency. We experimentally explore and theoretically model phase-sensitive parametric mechanical amplitude amplification and thermomechanical noise squeezing and detect both effects by an optomechanical readout scheme. Finally, we demonstrate that the amplification of the mechanical amplitude by parametric frequency modulation can be used to build a novel type of phasesensitive microwave amplifier. In contrast to the common microwave amplification scheme in optomechanical circuits by driving the cavity on the blue sideband, our technique allows for simultaneous cooling of the mechanical element and in principle is quantum-limited.