In a recent Letter [Opt. Lett. 24, 584 (1999)], Gori analyzed polarization
gratings and proposed using them as a tool to measure Stokes parameters. Mo
st of his analysis dealt with the near field, but practical exploitation of
his approach relies on the far field. A discussion focusing on the far fie
ld is presented, and recipes are suggested for actual implementations of su
ch devices. (C) 1999 Optical Society of America.