Patent ID: 8004688
Filing Date: 2011-08-23
Classification: G01B,Y10T

Abstract:
1. A broadband scanning interferometry system comprising: interferometer optics for combining test light from a test object with reference light from a reference object to form an interference pattern, wherein the test and reference light are derived from a common light source; a scanning stage configured to scan an optical path difference (OPD) between the test and reference light; a detector system for recording the interference pattern for each of a series of OPD increments, wherein the frequency of each OPD increment defines a frame rate, the detector system further configured to generate multiple monitor interferometry signals each indicative of changes in the OPD as the OPD is scanned, where there is phase diversity among the monitor interferometry signals; and an electronic processor electronically coupled to the detection system and scanning stage and configured to process the monitor interference signals based on the phase diversity to determine information about the OPD increments having sensitivity to perturbations to the OPD increments at frequencies greater than the frame rate.