Near-Field GHz Rotation and Sensing with an Optically Levitated Nanodumbbell

Abstract

A levitated nonspherical nanoparticle in a vacuum is ideal for studying quantum rotations and is an ultrasensitive torque detector for probing fundamental particle−surface interactions. Here, we optically levitate a silica nanodumbbell in a vacuum at 430 nm away from a sapphire surface and drive it to rotate at GHz frequencies. The relative linear speed between the tip of the nanodumbbell and the surface reaches 1.4 km s −1 at a submicrometer separation. The rotating nanodumbbell near the surface demonstrates a torque sensitivity of (5.0 ± 1.1) × 10 −26 N m Hz −1/2 at room temperature. Moreover, we probed the near-field laser intensity distribution beyond the optical diffraction limit with a nanodumbbell levitated near a nanograting. Our numerical simulations show that the system can measure the Casimir torque and will improve the detection limit of non-Newtonian gravity by several orders of magnitude.

Investigating and Controlling the Libration and Rotation Dynamics of Nanoparticles in an Optomechanical System

“…Within the framework of the washboard potentials and consideration of the initial librational/rotational kinetic energy of nanoparticles, hysteresis-loop bistabilities are straightforwardly understood. Our observations establish essential foundations for developing quantum precision measurement techniques 1,13,50 and exploring inherent frontier physical problems in mesoscopic lasermatter interactions 6,21,51 with respect to the rotational degrees of freedom. The power of the 532 nm detection laser is maintained at a substantially lower level (~10 mW) than that of the 1064 nm trapping laser (~60-120 mW) to ensure that the control exerted by the 1064 nm trapping laser over the levitated nanoparticle is not compromised.…”

Optical Torque Calculations and Measurements for DNA Torsional Studies

“…Our work facilitates understanding of the AOT instrumentation considerations and single-molecule data interpretation. Although this work focuses on quartz cylinders, it can be readily extended as a general model for optical force and torque calculation regardless of the size, shape, composition, and orientation of a trapped object (46)(47)(48). It has valuable potential for broader usage in developing and exploring novel nanotechnologies coupled with the AOT.…”

Giant enhancement of vacuum friction in spinning YIG nanospheres

“…in the symmetrized version of the FDT [18], which leads to δ(ω + ω ′ ) in equation (8). This is different from the FDT for averaging ⟨H f l i (ω)H f l * j (ω ′ )⟩, which is proportional to δ(ω − ω ′ ).…”

“…The physics of rotating nanoparticles is gaining more attention as recent technological advancements provide experimental platforms for rotating levitated nanoparticles at GHz speeds [1][2][3][4][5][6][7][8]. Besides having implications in the fields of quantum gravity [9], dark energy detection [10], and superradiance [11], rotating nanoparticles are crucial for studying the effects of quantum vacuum fluctuations [12][13][14][15][16][17].…”