The behavior of achromatic 90 and 180° phase retarder devices has been computed. These devices are made of three right-angle prisms so that the transmitted beam is not deflected or deviated from its incoming direction although the beam has suffered four internal reflections. Conventional BK-7 prisms andquartz prisms can be used as achromatic 180 and 90° phase retarders if suitable dielectric coatings are applied to the reflecting surfaces. With other glass types extremely achromatic 180° retarders can be obtained with <0.2% deviation from 180° throughout the visible wavelength range. This is five times better than the so-called superachromatic retarders made of several birefringent plates of different materials.
© 1984 Optical Society of America
I. Filinski and T. Skettrup, "Achromatic phase retarders constructed from right-angle prisms: design," Appl. Opt. 23, 2747-2751 (1984)