Optical and magnetic measurements of gyroscopically stabilized graphene nanoplatelets levitated in an ion trap

Abstract

Using optical measurements, we demonstrate that the rotation of micron-scale graphene nanoplatelets levitated in a quadrupole ion trap in high vacuum can be frequency locked to an applied radio frequency electric field E rf . Over time, frequency locking stabilizes the nanoplatelet so that its axis of rotation is normal to the nanoplatelet and perpendicular to E rf . We observe that residual slow dynamics of the direction of the axis of rotation in the plane normal to E rf are determined by an applied magnetic field. We present a simple model that accurately describes our observations. From our data and model we can infer both a diamagnetic polarizability and a magnetic moment proportional to the frequency of rotation, which we compare to theoretical values. Our results establish that trapping technologies have applications for materials measurements at the nanoscale. * These authors contributed equally to this work. P.N. is currently

Initiating revolutions for optical manipulation: the origins and applications of rotational dynamics of trapped particles

“…In complementary observations, gyroscopic stabilisation of the translational motion [145,213] and the orientation [173] has been observed by rotating particles at high speed. Coupling of rotational and translational degrees of freedom has also been shown for certain lower-symmetry particle morphologies, such as disks [226], while coupling between rotational and translational modes can also be enhanced in an optical cavity [227,228] or by painting a spot on the surface of a sphere and performing a continuous joint measurement of two motional modes [229].…”

“…As pressures approach the ultra-high vacuum range (typically < 10 À 6 mbar), the drag produced by the surrounding molecules is negligible and the rotation rate of levitated nanoparticles is limited only by the material properties of the particle [50,81,[172][173][174][175]: eventually the centrifugal force acting on the particle will cause it to be ripped apart. Thus rotational motion provides an interesting new platform to test the material properties of the particle under extreme conditions.…”

Levitodynamics: Levitation and control of microscopic objects in vacuum

“…In the subsequent years, the toolbox expanded to include techniques borrowed from the atom-trapping community. The development of electrostatic and magnetic levitation made it possible to overcome excessive photoheating of the trapped specimen [17,18] and extended levitation to magnets [19][20][21][22], metals [23], diamond with quantum emitters [24][25][26][27], liquid droplets [28], graphene flakes [29], and even superfluid helium droplets [30].…”

Precession Motion in Levitated Optomechanics

“…Thus, precession motion is a degree of freedom that could be utilised for torque sensing with the sensitivities to resolve single electron [39] and even nuclear spins [24] at low pressure. This work paves the way for gyroscope applications, as shown in [40]. The precession motion can also be used for dynamical model selection to distinguish between quantum and classical evolution due to the inherent nonlinearities in rotation motion [41], if sufficient coherence can be prepared.…”