Q-factor control of a microcantilever by mechanical sideband excitation

TL;DR

This paper demonstrates Q-factor control of a microcantilever by mechanically exciting its modes at sum and difference frequencies, enabling amplification or damping of its fundamental mode through a cavity-optomechanics analogy.

Contribution

It introduces a novel method of controlling a microcantilever's Q-factor using mechanical sideband excitation based on mode coupling and geometric nonlinearity.

Findings

Q-factor can be significantly enhanced or suppressed.

Mechanical sideband excitation effectively couples vibrational modes.

The approach mimics cavity-optomechanics principles.

Abstract

We demonstrate the coupling between the fundamental and second flexural mode of a microcantilever. A mechanical analogue of cavity-optomechanics is then employed, where the mechanical cavity is formed by the second vibrational mode of the same cantilever, coupled to the fundamental mode via the geometric nonlinearity. By exciting the cantilever at the sum and difference frequencies between fundamental and second flexural mode, the motion of the fundamental mode of the cantilever is amplified and damped. This concept makes it possible to enhance or suppress the Q-factor over a wide range.