SYSTEM AND METHOD FOR INTERFEROMETRIC AUTOFOCUSING

The present invention includes a camera configured to collect light reflected from the surface of a specimen, a two beam interference optical system including: an illumination source; a reference mirror configured to reflect substantially less light from a center region than from a peripheral region; and a first beam splitter configured to direct a first portion of light from the illumination source along an object path and a second portion of light from the illumination source along a reference path, wherein the camera and reference mirror are arranged such that light reflected from the reference mirror does not impinge on a FOV of the camera; and an autofocusing system disposed along a secondary optical axis, wherein the autofocusing system is configured to analyze one or more interference fringes created by a superposition of light reflected from the specimen surface and the peripheral region of the reference mirror surface.