Mechanical Verification

Calipers, micrometers and a variety of gauges are used to measure physical dimensions. An accurate height gauge is used for extremely accurate thickness measurements (+/- 0.05 microns) of waveplates. Waveplates additionally are qualified by optical retardance measurements.

Critical angular dimensions are measured using a Trioptics Precision Autocollimator / Goniometer. Readings from this automated instrument are accurate to +/- 0.4 arcseconds.

For a radius as long as 3.0 meters, the radius and surface figure of spherical surfaces can be measured interferometrically with our special radius scale. Radius distance accuracy is on the order of 5 microns. We also can measure parts with a longer radius of curvature directly by using a special Foucault test bed that utilizes a slit source and knife-edge. Typically, for these parts with longer radius of curvature we obtain an accuracy of +/- 0.1% of the radius, e.g. +/- 2.5 cm for a 25 meter focal length.