Patent ID: 7495770
Filing Date: 2009-02-24
Classification: G01B,G03F

Abstract:
1. An apparatus, comprising: an input assembly positioned to receive a beam emitted from a light source comprising a first component beam and a second component beam, the first and second component beams having orthogonal polarization states, wherein the input assembly is configured to change a dimension of the first component beam relative to the dimension of the second component beam so that the second component beam has a smaller cross-sectional dimension than the first component beam; and an interferometer positioned to receive the first and second component beams from the input assembly, the interferometer being configured to direct the first and second component beams along separate paths, where the first component beam contacts a measurement object, and to recombine the first and second component beams to provide an output beam that comprises information about an optical path difference between the different paths.