Abstract
When a light beam impinges on two interacting objects of subwavelength size, a spatially confined electromagnetic field arises in the immediate proximity of the particles. In scanning probe microscopy, short-range forces induced by this electromagnetic near-field change the magnitude of the probe tip-substrate interaction. In this letter we analyse the physical process responsible for these forces in the context of the localized field susceptibility method. © 1994 IOP Publishing Ltd.