Retarders based on total internal reflections are discussed. Quarterwave retardation can be obtained by a single reflection when one is using material of high refractive index (≥2.4), as it is available for the IR range. Alternatively, the influence of the beam divergence can he efficiently compensated for. Several optical designs and first results are presented.
E. H. Korte, B. Jordanov, D. Kolev, and D. Tsankov, "Total Reflection Prisms as Achromatic IR Retarders," Appl. Spectrosc. 42, 1394-1400 (1988)