Abstract: Various technologies for providing an operator of a focused ion beam (FIB) system with navigational and processing data are described herein. An exemplary system includes a broadband light source and a narrowband light source that emit light to a target of the FIB. An optical detector receives reflections of the broadband light from the target and outputs data that is used to generate two-dimensional images of the target in a region near a location of incidence of the FIB at the target. An interferometer receives reflections of the narrowband light from the target and outputs data indicative of an interference pattern of the narrowband reflections. A computing device computes a thickness of one or more material layers that make up the target based upon the interference pattern. A two-dimensional image of the target and an indication of the computed thickness are then displayed to the operator of the FIB.