A working design of a simple retardance meter is indicated. The device permits direct, quick, and accurate measurement of the retardance, for example, of an oriented polymeric film which is intended for use as a phase changer plate in the production of elliptically polarized light. The method involves the direct compensation of the sample’s retardance using the calibrated retardance of a mica crystal which is variably tilted about one of its two principal planar axes. Several suggestions relating to the optical design, assembly, and calibration of the device are included.
Albert S. Makas, "A Practical Design of a Simple Retardance Meter," Appl. Opt. 6, 1773-1776 (1967)