Waveplates retardance multispectral metrology with a Wollaston prism generated fringe field

The Variable Wavelength Interferometry (VAWI) for measuring the retardance of waveplates constitutes the core of this paper. The classical procedure based on finding coincidences and anti-coincidences of the object fringe pattern with respect to the empty field pattern is replaced by continuous phase registration. Further work is focused at a new algorithm and modified optical architecture of the interferometer. The results are compared one another demonstrating advantages of the new approach. The interferometer utilizes a set of Wollaston prisms that are built in a classical microscope. The retardance can be measured across the visible spectrum with low uncertainty. Being insensitive to environmental factors the system is suitable for industrial applications.