Mirror effect in atomic force microscopy profiles enables tip reconstruction

In this work, the tip convolution effect in atomic force microscopy is revisited to illustrate the capabilities of cubic objects for determination of the tip shape and size. Using molecular-based cubic nanoparticles as a reference, a two-step tip reconstruction process has been developed. First, the tip-to-face angle is estimated by means of an analysis of the convolution error while the tip radius is extracted from the experimental profiles. The results obtained are in good agreement with specification of the tip supplier even though the experiments have been conducted using real distribution of nanoparticles with dispersion in size and aspect ratio. This demonstrates the reliability of our method and opens the door for a more accurate tip reconstruction by using calibration standards.

Pseudo-random Path Generation Algorithms and Strategies for the Surface Quality Improvement of Optical Aspherical Components

This study proposes two path generation algorithms to diminish the superposition of the convolution effect on the polishing path in computer-controlled optical surfacing. According to the polishing of aluminum-alloy based hyperboloid optical components, different proportions of polishing agents were blended. Then, the surface roughness of the optical components were determined through a validation experiment of the algorithms. Furthermore, the relationship between surface roughness and the polishing agent concentration, and the compensation strategies for surface roughness were analyzed. The results show that the two algorithms effectively compensated for surface waviness. The findings support the strategies for improving the surface quality of optical components with aspherical surfaces.

SPM Tip Convolution

Why is it that tip convolution effects rotate with the scan angle in a Nanoscope-based AFM (and possibly other systems)? The tip certainly doesn't rotate in its holder as the scan angle is changed! I posed this question on the SPM mailing list, and got several answers in return, but I was still puzzled until I put all of them together and thought a while. However, I may not be the only puzzled soul out there, so let me attempt to summarize what I've come to understand:A good way to think about this is to consider a righttriangle tip approaching a cube on a surface:If the tip approaches the cube along the plane of the page screen, the left side of the cube will appear sharp in an AFM image and the right side of the cube will have a slant introduced into it due to a tip convolution effect.