Feedback Control and Characterization of a Microcantilever Using Optical Radiation Pressure

TL;DR

This paper presents a novel optical feedback method to control and characterize a microcantilever's dynamics by using radiation pressure, achieving significant reductions in its effective quality factor and temperature, and proposing a new spring constant measurement technique.

Contribution

The work introduces a feedback control scheme using optical radiation pressure to regulate microcantilever response and a method to determine its spring constant.

Findings

Reduced Qeff and Teff by over 15 times

Implemented a phase-shifted optical force feedback

Proposed a radiation pressure-based spring constant measurement

Abstract

We describe a method for feedback-regulation of a microcantilever's response using optical radiation pressure. One laser measures the position of the cantilever and another laser applies a force that is a phase-shifted function of that position. The force is due solely to the momentum of the photons in the laser. The feedback changes the microcantilever's effective quality factor Qeff and effective temperature Teff. Reduction of both Qeff and Teff by more than a factor of 15 is demonstrated. Additionally, we suggest a method for determination of a microcantilever's spring constant using the known force exerted on it by radiation pressure.