Technique - (13) Pulsed optomechanics / back-action-evading measurement

Type: Experimental

Description: Pulsed radiation-pressure interactions for back-action-evading position measurement, mechanical state squeezing, and quantum state tomography of nano/micromechanical resonators.

Department(s)/lab(s): Physics & Astronomy โ€“ AMOPP | UCL Optomechanics Group (Barker Group) @ UCL
Summary:

Barker leads the UCL Optomechanics Group, focusing on levitated nano/micro-oscillators in vacuum. Research directions: (1) Six-degree-of-freedom cooling โ€” demonstrated simultaneous cavity cooling of all 6 DOF of a levitated nanoparticle (Nature Physics 2023, with Monteiro); (2) Sympathetic cooling of two nanoparticles via Coulomb interaction, squeezing transfer (Phys. Rev. Research 2023); (3) Dark matter searches โ€” levitated nanoparticles as directional dark matter sensors sensitive to nuclear recoil and momentum transfer; QTFP-funded project 'Development of Levitated Quantum Optomechanical Sensors for Dark Matter Detection'; (4) Controlling mode orientations for directional force sensing near the quantum limit; (5) Quantum macroscopic superposition tests. Closely collaborates with Monteiro (theory), Bose (quantum entanglement tests), and Ghag (dark matter).

Department(s)/lab(s): Physics / Niels Bohr Institute | Copenhagen Center for Biomedical Quantum Sensing (CBQS) @ UCPH
Summary:

Tulio Brito Brasil focuses on multimode quantum optics, squeezed and entangled states of light, and their application for quantum sensing and communication. Research: (1) generation of two-colour high-purity EPR photonic states; (2) squeezed light for quantum noise reduction in measurement; (3) continuous variable quantum optics protocols for networks. Recently joined QUANTOP at NBI.

Department(s)/lab(s): Physics / LKB | Optomechanics and Quantum Measurements (Cohadon Lab) @ ENS Paris
Summary:

Pierre-Franรงois Cohadon leads the optomechanics and quantum measurements group at LKB (ENS site). Research: (1) mechanical quantum systems and back-action-evading measurement; (2) gravitational wave detector enhancement โ€” white-light cavity proposals to extend GW sensitivity; (3) quantum optomechanical sensing of forces and fields. The group was key to the LKB optomechanics tradition and is affiliated with Virgo/LIGO enhancement proposals.

Department(s)/lab(s): Physics โ€“ Laboratoire Kastler Brossel, Sorbonne Universitรฉ / ENS | Optomechanics and Quantum Measurements Group (Cohadon & Heidmann / LKB) @ Sorbonne
Summary:

Cohadon and Heidmann co-lead the Optomechanics and Quantum Measurements group at LKB. Research directions: (1) Back-action evasion and Standard Quantum Limit (SQL) โ€” early demonstration of radiation-pressure back-action in a micro-mirror (Nature 2006), subsequent beating of SQL via quantum correlations; (2) Micro/nanomechanical resonators โ€” 2D photonic crystal deformable slabs, membrane-in-the-middle cavities, micropillar resonators for radiation-pressure optomechanics; (3) Superconducting qubitโ€“macroscopic membrane coupling โ€” Jacqmin & Delรฉglise team: resonant coupling of transmon qubit to MHz membrane oscillator, tracking quantum motion with 300 repeated interactions (2025); high-impedance hyperinductors for electromechanics; (4) Gravitational wave detector contributions โ€” VIRGO/LIGO data analysis and quantum noise modeling. Applications include back-action-evading force sensing and tests of quantum mechanics at macroscopic scales.

Department(s)/lab(s): Physics and Astronomy | Quantum Technologies for Fundamental Physics (Fuentes) @ Southampton
Summary:

Ivette Fuentes' group uses quantum information and metrology to probe fundamental physics at the interface of quantum theory and general relativity. Research: (1) quantum sensing of gravitational waves using relativistic quantum systems; (2) quantum clock synchronization and gravitational decoherence; (3) dark energy detection using quantum sensors; (4) quantum reference frames in curved spacetime. Bridges quantum sensing with gravitational physics.

Department(s)/lab(s): Physics โ€“ Institute of Physics (IPHYS) | Laboratory of Photonics and Quantum Measurements (K-Lab) @ EPFL
Summary:

Kippenberg leads the Laboratory of Photonics and Quantum Measurements (K-Lab) at EPFL, pioneer of chip-scale microresonator frequency combs and cavity optomechanics. Research directions: (1) Soliton microcombs โ€” dissipative Kerr solitons in Si3N4 microresonators for massively parallel coherent optical communications, precision ranging/LiDAR (Science 2018, Nature 2017); dual-chirped microcomb parallel ranging at megapixel rates; (2) Room-temperature quantum optomechanics โ€” phononic-crystal-patterned Si3N4 membrane-in-the-middle cavity reduces frequency noise 700ร—, observing quantum backaction at room temperature (Nature 2024); (3) Superconducting circuit optomechanics โ€” topological lattices, electromechanical sensing (Nature 2022); (4) Free-electronโ€“photon interactions in microresonators. Spin-off companies and strong industry ties. Over 85,000 citations, h-index ~80.

Department(s)/lab(s): Physics / Niels Bohr Institute | QUANTOP โ€“ Quantum Optics Center (Polzik Lab) @ UCPH
Summary:

Eugene Polzik's QUANTOP centre uses hot and ultracold atomic spin ensembles and mechanical membranes to generate squeezed, entangled, and single-photon states for quantum sensing and communication. Key directions include: (1) atomic magnetometry and electromagnetic induction imaging for biomedical applications (MEG/MCG-quality sensors); (2) entanglement between a macroscopic mechanical oscillator and an atomic spin ensemble; (3) quantum memory for light; (4) back-action-evading measurement schemes beyond the SQL; and (5) optical preamplification for MRI. QUANTOP heads the Copenhagen Center for Biomedical Quantum Sensing (CBQS), targeting quantum-enhanced disease diagnostics.

Department(s)/lab(s): D-MAVT โ€“ 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 โ€” ultra-sensitive force/acceleration sensing, directional dark matter detection with levitated sensors; (3) Meta-atom levitation โ€” Mie-resonance high-permittivity particles in optical traps for extreme light-matter interaction; (4) Optofluidics โ€” structured light for photothermal fluid control; (5) Cancer phototherapy โ€” photothermal nanoparticle applications. Pioneer in nanoplasmonic tweezers, thermoplasmonics, and on-chip biosensing. Key co-author of Science levitodynamics review (2021).

Department(s)/lab(s): Quantum Nanoscience | Rossi Lab @ TU Delft
Summary:

Massimiliano Rossi's lab focuses on levitated systems, optical tweezers, and quantum measurement. Research: (1) optically levitated nanoparticles for force sensing and zeptonewton-scale measurements; (2) quantum measurement and control of levitated systems approaching the quantum ground state; (3) back-action-evading measurement schemes for levitated oscillators; (4) exploring quantum-to-classical transitions. The lab is developing levitated systems as sensors for dark matter and gravitational waves.

Department(s)/lab(s): Physics โ€“ QOLS / Light Community | Quantum Measurement Lab (Vanner) @ Imperial
Summary:

Vanner leads the Quantum Measurement Lab, combining experiment and theory. Key research areas: (1) Cavity quantum optomechanics โ€” developed a theoretical framework capturing nonlinear radiation-pressure beyond the linearised approximation, showing deterministic mechanical Wigner-negativity generation; demonstrated mechanical position-squared measurements in Nature Comms (2016); thermal noise squeezing by 36 dB (Nat. Comms 2013); (2) Brillouin-Mandelstam scattering โ€” demonstrated strong coupling to high-frequency phonons (Optica 2019); single-phonon addition/subtraction via Brillouin (PRL 2021); quantum state tomography with non-Gaussianity; (3) Hybrid quantum systems โ€” 'displacemon' architecture (nanobeam magnetically coupled to superconducting qubit, PRX 2018) for testing objective collapse and dark matter; (4) Quantum gravity tests โ€” proposals for testing the generalised uncertainty principle (GUP) using optomechanical protocols. UKRI QTFP fellowship.