Optimal beam splitters for the division-of-amplitude photopolarimeter.

Optimal optical parameters of the beam splitter that is used in the division-of-amplitude photopolarimeter are determined. These are (1) 50%-50% split ratio of the all-dielectric beam splitter, (2) differential phase shifts in reflection and transmission delta(r) and delta(t) that differ by +/- pi/2, and (3) ellipsometric parameters (psi(r), psi(t)) = (27.368 degrees, 62.632 degrees) or (62.632 degrees, 27.368 degrees). It is also shown that for any nonabsorbing beam splitter that splits incident unpolarized light equally, the relationship psi(r) + psi(t) = pi/2 is always satisfied.