Development of an atomic force microscope with capability of circumferential profiling

In order to measure precisely the circumferential profiles of small cylindrical and spherical objects, we have developed an atomic force microscope that consists of a cantilevered probe, an optical lever system for detecting the probe deflection, and an air bearing sample stage. This rotating atomic force microscope (R-AFM) provided a roundness profile of φ 2mm bearing ball, and the profile was compared with that measured by a commercial roundness instrument. Since the R-AFM uses a sharper tip and a lower applied force than the instrument, the roundness profile obtained by the R-AFM showed higher resolution than that by the commercial instrument. Measurements of circumferential profiles of a φ30μm tungsten wire confirmed that the R-AFM has high accuracy for measuring circumferential profiles of small cylindrical objects. Possible applications of the R-AFM have been demonstrated through obtaining circumferential images of an optical fiber, a human hair, and a spine on an insect's leg.