Technique - (3) Hybrid RF–optical levitation (Paul trap + optical tweezer)

Type: Experimental

Description: Combining RF electrodynamic and optical trapping to levitate and cool absorbing or charged particles in vacuum.

Department(s)/lab(s): D-ITET – Photonics Laboratory | Photonics Laboratory (Novotny Group) @ ETH Zurich
Summary:

Novotny leads the Photonics Lab with a primary focus on levitodynamics. Research directions: (1) Ground-state cooling of levitated nanoparticles — demonstrated quantum control and motional ground state cooling of silica nanospheres in cryogenic free space (Nature 2021) and all 6 degrees of freedom simultaneously via coherent scattering (Nature Physics 2023); (2) Quantum delocalization and matter-wave interference of levitated nanoparticles (arXiv 2408.01264, 2024); (3) Cavity-mediated long-range interactions between multiple levitated nanoparticles, enabling collective quantum sensing arrays; (4) Optical cold damping, measurement-free coherent feedback (PRL 2025); (5) 2D optoelectronics — graphene/hBN/TMD-based laser detectors and modulators. Heavily cited levitodynamics review (Science 2021, joint with Quidant). Group feeds into applications in quantum-limited force sensing and macroscopic quantum tests.

Department(s)/lab(s): D-MAVT – Nanophotonic Systems Laboratory | Nanophotonic Systems Laboratory (Quidant Group) @ ETH Zurich
Summary:

Quidant leads the Nanophotonic Systems Laboratory, developing hybrid integrated levitation platforms combining optical and RF fields. Research directions: (1) Measurement-free coherent optical feedback cooling of levitated nanoparticles (PRL 2025, phonon occupations ~100s); (2) Quantum sensing applications — ultra-sensitive force/acceleration sensing, directional dark matter detection with levitated sensors; (3) Meta-atom levitation — Mie-resonance high-permittivity particles in optical traps for extreme light-matter interaction; (4) Optofluidics — structured light for photothermal fluid control; (5) Cancer phototherapy — photothermal nanoparticle applications. Pioneer in nanoplasmonic tweezers, thermoplasmonics, and on-chip biosensing. Key co-author of Science levitodynamics review (2021).

Department(s)/lab(s): Physics and Astronomy | Ulbricht Lab @ Southampton
Summary:

Hendrik Ulbricht's group pioneers levitated optomechanics and macroscopic quantum systems. Research: (1) optical levitation of nanoparticles for zeptonewton force sensing and quantum-to-classical transition tests; (2) magnetic levitation of micromagnets (diamagnetically stabilised) as ultralight dark matter detectors and magnetometers (fT/√Hz sensitivity demonstrated with LeMaMa levitated ferromagnet); (3) spin entanglement witness for quantum gravity (BMV experiment — levitated diamond with NV centre); (4) tests of the Diósi-Penrose model of wavefunction collapse. Multiple Reviews of Modern Physics; active in macroscopic quantum physics community.