Imaging polarimeter with high angle resolution

The polarizer and the analyzer of the polarimeter are realized by Glan-Thompson-prisms which are characterized by a very high extinction. In this set-up only the object under test is located between the prisms, i.e. the polarization properties of the light are not distributed by optical components and high angle resolution is achieved. The disadvantage of these prisms is the use of the extraordinary ray causing an axial astigmatism. In the paraxial domain this astigmatism can be corrected by a simple cylindrical lens. However, this leads to a distorted scaling in the image, because the scaling in the active and the inactive direction of this lens is different. This disadvantage can be omitted by using a cylindrical optic which consists of at least two lenses having opposite sign of their focal length. The calculated result for this optic are verified experimentally.