SURFACE PROFILING WITH SCANNING OPTICAL MICROSCOPES USING 2-MODE OPTICAL FIBERS

A scanning optical microscope system is proposed that uses a slightly laterally offset optical fiber. The fiber is capable of supporting two modes, and it is shown that by detecting the interference between these modes the response to surface height is linear in the focal region. This linearity permits noncontacting surface profilometry to be readily obtained for specimens of uniform reflectivity. For other specimens, a simple feedback system is introduced to obtain surface profiles as well as intensity-coded height images.