Scanning Optical Head with Nontilted Reference Beam: Assuring Nanoradian Accuracy for a New Generation Surface Profiler in the Large-Slope Testing Range
Figure 9
(a) Apply extra angle device to test pitch error; (b) take sample and reference beam tests in sequence; (c) use nontilted reference with tilted sample beam for plane mirror test; (d) employ second optical head; (e) assure non-reference beam by using pentaprism scan for plane mirror test; (f) alternatively switching on/off of sample and reference beams.
