Our cavity optomechanics subgroup, led by Hilel Hagai Diamandi, achieved a major milestone in quantum optomechanics by cooling a macroscopic mechanical resonator with a mass of roughly 7.5 micrograms to its quantum ground state and published this work in Nature Physics. Using a microfabricated high-overtone bulk acoustic wave resonator (μHBAR) coupled to an optical cavity, we reached an average occupancy of fewer than 0.4 phonons, starting from about 22. Remarkably, this was done without any absorption-induced heating, a common challenge in laser-cooled systems.
Our μHBAR platform combines ultrahigh mechanical quality factors with coherence times exceeding one millisecond and the ability to interact strongly with light at gigahertz frequencies. This unique combination enables high-performance cooling using just a few milliwatts of optical power, offering clear advantages over many nanoscale devices that suffer from heating and dephasing.
These results open the door to new regimes of macroscopic quantum control with potential applications in quantum sensing, signal transduction, and precision metrology. This demonstration also paves the way for scalable platforms that can integrate long-lived mechanical elements with advanced photonic circuits for next-generation quantum technologies. Read more here and here