Patent ID: 7057739
Filing Date: 2006-06-06
Classification: G01B,G03F

Abstract:
1. Interferometric apparatus comprising: a polarizing beam-splitting interface positioned to separate an input beam into two orthogonally polarized beams; interferometer optics positioned to receive a first set of beams derived from one of the orthogonally polarized beams and a second set of beams derived from the other of the orthogonally polarized beams; and intermediate optics positioned to derive the first set of beams from one of the orthogonally polarized beams and derive the second set of beams from the other of the orthogonally polarized beams, wherein the interferometer optics are configured to direct the beams in the first set to contact different respective locations of a measurement object at least once, and subsequently combine each beam in the first set with a corresponding beam from the second set of beams to produce a corresponding output beam comprising information about changes in the position of the measurement object with respect to a different degree of freedom.