Nanowerk June 29, 2022
Interferometric methods for detecting the motion of a levitated nanoparticle provide a route to the quantum ground state, but such methods are currently limited by mode mismatch between the reference beam and the dipolar field scattered by the particle. An international team of researchers (Austria, UK) has demonstrated a self-interference method to detect the particle’s motion that solves this problem. They confined a charged dielectric nanoparticle in high vacuum using a Paul trap and a mirror retro-reflected the scattered light. They measured the particle’s motion with a sensitivity of 1.7×10−12m/√Hz, corresponding to a detection efficiency of 2.1%, with a numerical aperture of 0.18. As an application of this method, they cooled the particle, via feedback, to temperatures below those achieved in the same setup using a standard position measurement. The work opens new possibilities for using levitated particles as sensors in quantum regimes…read more. TECHNICAL ARTICLEÂ
Basic principles of the self-homodyne technique. Credit: Phys. Rev. Lett. 129, 013601, 28 June 2022Â