| 摘要 |
<p>An apparatus including: a multi-axis interferometry system configured to receive an input beam and direct at least two beams derived from the input beam to contact different locations on a measurement object to monitor changes in an angular orientation of the measurement object; a beam steering assembly having a beam steering element positioned to direct the input beam into the interferometry system and a positioning system to selectively orient the beam steering element relative to the interferometry system; and a control circuit which during operation orients the beam steering element based on the changes in the angular orientation of the measurement object monitored by the interferometry system.</p> |
