This paper analyzes layouts for constructing compensators and shows that a compensator with collinear input and output rays can be created by using four cemented quartz or fluorite prisms, making it possible to obtain a phase shift of D5 pi/2 in a wide spectral range. When a compensator is used for a single wavelength, the material of the prisms can be varied while simultaneously depositing interference layers on their working faces.
I. S. Gainutdinov, E. A. Nesmelov, A. S. Nikitin, A. N. Borisov, R. S. Sabirov, and A. V. Mikhailov, "The use of interference coatings in the fabrication of quarter-wave compensators," J. Opt. Technol. 70, 661-664 (2003)