Hetet's group couples NV-center ensemble electron spins in electrically or optically levitated micro-diamonds to the mechanical (rotational and translational) degrees of freedom of the host particle, demonstrating spin-dependent torques strong enough to deflect a cantilever, spin-cooling of levitated motion, and NMR performed on a levitating microparticle. This complements the well-established line of NV-ensemble quantum sensing experiments (DEER, NMR, T1-relaxometry) that reach pT/sqrt(Hz)-class sensitivities, extending the toolbox toward mechanical and single-atom/single-spin readout.

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.