Patent ID: 8797537
Filing Date: 2014-08-05
Classification: G01B

Abstract:
1. An interferometer, comprising: a first beam splitter positioned to derive test light and reference light from input light and to direct the test light along a first path to contact a test object and direct the reference light along a second path different from the first path; a second beam splitter positioned in the first and second paths and arranged to combine the reference light with test light after the test light contacts the test object; an optical element positioned in the second path and arranged to direct reference light from the first beam splitter toward the second beam splitter; a detector positioned to receive the combined test and reference light; and an objective arranged to image the test object and a virtual reference surface onto the detector, wherein the virtual reference surface corresponds to a virtual surface optically conjugate to the detector between the first and second beam splitters; wherein the first and second paths between the first and second beam splitters, in combination with the optical element positioned in the second path, define a geometry corresponding substantially to a triangle.