Atomic force microscope for generating a small incident beam spot

摘要

An atomic force microscope utilizes an optical system having a numerical aperture sufficient with the wavelength of light of an incident beam (44) to form a spot on a cantilever (14) having a size of 8 micrometers or less in at least one dimension. An adjustable aperture (34) can be utilized to control the size and/or shape of the incident beam spot on the cantilever (14). Portions of the incident beam and the beam reflected from the cantilever overlap and are directed so that the plane of focus of the incident beam is parallel to the plane of the cantilever (14). The incident and reflected light beams are separated by polarization using a beamsplitter (40) in conjunction with a quarterwave plate (42). Focussing can be accomplished with a confocal viewing system coupled with a translatable focussing lens common to the optical system and the viewing system.