Optical configuration for measurement device using emitter material configuration with quadrant photodetectors

A scanning probe responsive in 3 axes is provided for use in a coordinate measuring machine. The scanning probe includes a frame, a stylus suspension portion and a stylus position detection portion. The stylus position detection portion includes a light source and a position indicating element that is fixed relative to the stylus coupling portion and that includes at least one emitter portion having an emitter material (e.g., phosphor) that inputs and absorbs light from the light source and responds by outputting excitation light. In various implementations, the excitation light is directed as measurement light along a measurement spot path (e.g., including a telecentric imaging configuration) to form a measurement spot at a spot location on a position sensitive detector (e.g., a quadrant-type photodetector), for which the spot location changes in response to a corresponding change in a position of the position indicating element and the stylus coupling portion.