In one aspect, the disclosure features methods that include using a microscope to direct light to a test object and to direct the light reflected from the test object to a detector, where the light includes components having orthogonal polarization states, varying an optical path length difference (OPD)...http://www.google.es/patents/US7978337?utm_source=gb-gplus-sharePatente US7978337 - Interferometer utilizing polarization scanning
