Nanoscale Torsional Optomechanics

TL;DR

This paper demonstrates nanoscale torsional resonators coupled to optical microdisks, achieving highly sensitive optomechanical measurements capable of detecting extremely small torques, advancing nanoscale sensing technologies.

Contribution

It introduces integrated nanoscale torsional optomechanical devices with fiber-based measurement, enabling ultra-sensitive torque detection at the nanoscale.

Findings

Achieved a thermomechanically calibrated noise floor of 7 fm/√Hz.

Detected torques as small as 4×10^-20 N·m.

Demonstrated on-chip integration with fiber-based optical coupling.

Abstract

Optomechanical transduction is demonstrated for nanoscale torsional resonators evanescently coupled to optical microdisk whispering gallery mode resonators. The on-chip, integrated devices are measured using a fully fiber-based system, including a tapered and dimpled optical fiber probe. With a thermomechanically calibrated optomechanical noise floor down to 7 fm/sqrt(Hz), these devices open the door for a wide range of physical measurements involving extremely small torques, as little as 4x10^-20 N*m.