# "Noiseless" thermal noise measurement of atomic force microscopy cantilevers

## TL;DR

This paper introduces a signal processing technique that significantly improves thermal noise measurement accuracy in AFM cantilevers by eliminating background noise, enabling better calibration and mode identification.

## Contribution

A novel method utilizing optical beam deflection sensors to remove background noise in thermal noise measurements of AFM cantilevers.

## Key findings

- Achieved two orders of magnitude enhancement in signal-to-noise ratio.
- Enabled calibration of stiff cantilevers using thermal noise.
- Facilitated easier identification of higher order modes.

## Abstract

When measuring quadratic values representative of random fluctuations, such as the thermal noise of Atomic Force Microscopy (AFM) cantilevers, the background measurement noise cannot be averaged to zero. We present a signal processing method that allows to get rid of this limitation using the ubiquitous optical beam deflection sensor of standard AFMs. We demonstrate a two orders of magnitude enhancement of the signal to noise ratio in our experiment, allowing the calibration of stiff cantilevers or easy identification of higher order modes from thermal noise measurements.