  An easily constructed and operated polarimeter precisely determines the
relative Stokes parameters that characterize the polarization of laser light.
The polarimeter is calibrated in situ without removing or realigning its
optical elements, and it is largely immune to fluctuations in the laser beam
intensity. The polarimeter's usefulness is illustrated by measuring
thermally-induced birefringence in the indium-tin-oxide coated glass field
plates used to produce a static electric field in the ACME collaboration's
measurement of the electron electric dipole moment.
