Quantum mechanics

Ecology

Biology

Radiation pressure

Optical tweezers

Optical force

Atomic physics

Economics

Classical mechanics

Rotation (mathematics)

Trapping

Geology

Oceanography

Physical chemistry

Polarization (electrochemistry)

Physics

Torque

Total angular momentum quantum number

Mathematics

Optics

Angular momentum

Geometry

Particle (ecology)

Momentum (technical analysis)

Chemistry

Finance

Physical Review Letters

We report on rotating an optically trapped silica nanoparticle in vacuum by transferring spin angular momentum of light to the particle's mechanical angular momentum. At sufficiently low damping, realized at pressures below $10^{-5}$ mbar, we observe rotation frequencies of single 100 nm particles exceeding 1 GHz. We find that the steady-state rotation frequency scales linearly with the optical trapping power and inversely with pressure, consistent with theoretical considerations based on conservation of angular momentum. Rapidly changing the polarization of the trapping light allows us to extract the pressure-dependent response time of the particle's rotational degree of freedom.

GHz Rotation of an Optically Trapped Nanoparticle in Vacuum