Fig. 11. The reflectance of the facet lens surface with paraboloid and sinusoidal
nipples as a function of the angle of incidence and polarization, for light of
wavelength 530 nm. The value of the refractive index of the facet lens medium
is 1.52 (Vogt, 1974). (A) The
reflectance for TE waves. (B) The reflectance for TM waves. For a smooth
surface, that is in the absence of nipples, the reflectance for TM waves falls
to zero at the Brewster's angle
=arctan(1.52)=56.7°. Both types of
nipples strongly reduce the reflectance at angles of incidence below 50°,
but at larger values the reflectance rapidly rises. A Brewster's angle only
exists in the absence of nipples.