Patent ID: 7061613

Claim:
A metrology device comprising: a polarization state generator, including an electromagnetic source, the polarization state generator produces an electromagnetic beam of known polarization state that is incident on a sample; a spatial variable phase retarder in the path of the electromagnetic beam after the sample; a polarizing beam splitter in the path of the electromagnetic beam after the spatial variable phase retarder, the polarizing beam splitter splitting the electromagnetic beam into a first beam having a first polarization state and a second beam having a second polarization state that is orthogonal to the first polarization state; and a first set of detector elements within the path of the first beam after the polarizing beam splitter and a second set of detector elements within the path of the second beam after the polarizing beam splitter, wherein the first set of detector elements and the second set of detector elements measure the intensity of the first beam and second beam, respectively, as a function of position.