An elongated object can be rotated around one of its short axes, like a propeller, or around its long axis, like a spinning top. Using optically levitated nanoparticles, short-axis rotation and libration have been systematically investigated in several recent studies. Notably, short-axis rotational degrees of freedom have been cooled to millikelvin temperatures and driven into gigahertz rotational speeds. However, controlled long-axis spinning has so far remained an unrealized goal. Here, we demonstrate controlled long-axis spinning of an optically levitated nanodumbbell with spinning rates exceeding 1 GHz. We show that the damping rate in high vacuum can be as low as a few millihertz. Our results open up applications in inertial torque sensing and studies of rotational quantum interference.

The Netherlands Organisation for Scientific Research (NWO)
Photonic Forces

Zielińska, J. A., van der Laan, F., Norrman, A., Reimann, R., Frimmer, M., & Novotny, L. (2024). Long-Axis Spinning of an Optically Levitated Particle: A Levitated Spinning Top. Phys.Rev.Lett., 132(25), 253601: 1–6. doi:10.1103/PhysRevLett.132.253601