Hong runs Hybrid Optical Quantum Technologies within Stuttgart's FMQ institute: optomechanical and opto-mechanical-spin hybrid devices used for quantum sensing and for tests of quantum mechanics at larger mass scales. Work covers cavity/phononic-crystal optomechanics driven toward the quantum regime (ground-state cooling, back-action-evading and quantum-limited displacement/force readout) and the coupling of diamond spin defects to mechanical motion, including levitated-diamond spin-mechanics -- where an NV inside a levitated particle both senses and controls the particle's motion. Relative to the established NV-ensemble quantum-sensing playbook (DEER, nanoscale NMR, T1 relaxometry at pT/sqrt(Hz) ensemble sensitivity), this is the same colour-centre physics, deliberately hybridized with mechanics: the sensing target shifts from magnetic field to force, acceleration and displacement, and the group sits alongside Wrachtrup's NV programme in the same building, which is a considerable practical advantage.
Safavi-Naeini's group engineers nanoscale optomechanical and electromechanical devices -- phononic-crystal membranes and superconducting-circuit-coupled resonators -- for quantum-limited force and displacement sensing and for coherent microwave-to-optical quantum transduction linking superconducting qubits to photonic quantum networks.
Albert Schliesser's group engineers ultracoherent phononic crystal membrane resonators with dissipation-dilution Q>10^9 and uses them for quantum optomechanics: ground-state cooling, back-action-evading measurement, optical quantum memory for single photons, and microwave-optical quantum transduction. Recent work has demonstrated a soft-clamped topological phononic waveguide (Nature 2025) and scanning force microscopy below the standard quantum limit. The group bridges fundamental quantum physics with novel sensors for electromagnetic fields and forces, and mechanical interfaces for hybrid quantum networks.
Verlot works on nano-optomechanics and quantum-limited displacement/force sensing with nanowire and levitated resonators, exploring ultrasensitive force detection and fundamental measurement limits. In the broader landscape of NV-centre ensemble quantum sensing (DEER, nano-NMR, T1 relaxometry) operating near pT/sqrt(Hz) sensitivity, this work is complemented by mechanical quantum sensors at the force-sensitivity frontier.