INTERFEROMETRISCHER SENSOR ZUR MESSUNG VON ABSTANDSAENDERUNGEN EINER KLEINEN FLAECHE

摘要

For the purpose of accurate measurement of small distance variations of a small measuring surface, there is arranged between the reference surface (17r) and measuring surface (15) in a Mirau-like interferometer arrangement a delay element (16v) which produces a difference in the path difference between a measuring beam (11m) and comparison beam (11v) of approximately a quarter-wave for two polarisation directions. The powers of the beams in these polarisation directions are measured by a detection device (18) which consists of a polarisation-dependent beam splitter (18s) and two detectors (18d, 18e).