Universal Vectorial and Ultrasensitive Nanomechanical Force Field Sensor

TL;DR

This paper introduces a highly sensitive nanomechanical method for imaging 2D vectorial force fields by tracking a nanowire's motion, revealing force topology and enabling nanoscale force measurements with attonewton sensitivity.

Contribution

The work presents a universal optomechanical approach to map vectorial force fields by analyzing nanowire eigenmode rotations and frequency shifts, a novel technique in nanoscale force sensing.

Findings

Achieved attonewton sensitivity in force measurements.

Demonstrated mapping of tunable electrostatic force fields.

Revealed force field topology through eigenmode analysis.

Abstract

Miniaturization of force probes into nanomechanical oscillators enables ultrasensitive investigations of forces on dimensions smaller than their characteristic length scale. Meanwhile it also unravels the force field vectorial character and how its topology impacts the measurement. Here we expose an ultrasensitive method to image 2D vectorial force fields by optomechanically following the bidimensional Brownian motion of a singly clamped nanowire. This novel approach relies on angular and spectral tomography of its quasi frequency-degenerated transverse mechanical polarizations: immersing the nanoresonator in a vectorial force field does not only shift its eigenfrequencies but also rotate eigenmodes orientation as a nano-compass. This universal method is employed to map a tunable electrostatic force field whose spatial gradients can even take precedence over the intrinsic nanowire properties. Enabling vectorial force fields imaging with demonstrated sensitivities of attonewton variations over the nanoprobe Brownian trajectory will have strong impact on scientific exploration at the nanoscale.