Patent ID: 7224466
Filing Date: 2007-05-29
Classification: G01B

Abstract:
1. A multi-axis interferometer comprising: a polarizing beam splitter positioned to split an input beam into a shared measurement beam and a shared reference beam; a first polarization-changing element along a path of the shared measurement beam from the polarizing beam splitter to a measurement reflector; a second polarization-changing element along a path of the shared reference beam from the polarizing beam splitter to a reference reflector; and beam-splitting optics that are along a path of the shared measurement beam after the shared measurement beam reflects from the measurement reflector, wherein the beam-splitting optics split the shared measurement beam into individual measurement beams that are directed into the polarizing beam splitter and subsequently reflected from the measurement reflector; and a plurality of retroreflectors respectively associated with measurement axes of the interferometer, wherein each of the retroreflectors is positioned to reflect a corresponding one of the individual measurement beams onto a path into the polarizing beam splitter,