Phase imaging with intermodulation atomic force microscopy

TL;DR

This paper introduces a method to extract phase information at intermodulation frequencies in intermodulation AFM, enhancing contrast in imaging of surface topography and material properties.

Contribution

It presents a novel procedure for phase extraction at IMPs in IMAFM, improving contrast and detail in AFM imaging.

Findings

Phase images reveal enhanced topographic contrast.

Material contrast is improved in phase imaging.

Method enables detailed surface characterization.

Abstract

Intermodulation atomic force microscopy (IMAFM) is a dynamic mode of atomic force microscopy (AFM) with two-tone excitation. The oscillating AFM cantilever in close proximity to a surface experiences the nonlinear tip-sample force which mixes the drive tones and generates new frequency components in the cantilever response known as intermodulation products (IMPs). We present a procedure for extracting the phase at each IMP and demonstrate phase images made by recording this phase while scanning. Amplitude and phase images at intermodulation frequencies exhibit enhanced topographic and material contrast.