The formalism applied to superelastic electron scattering from laser-excited atoms has to date assumed perfect polarization of the laser light. We consider the effects of imperfect polarization, deriving an expression for the superelastic scattering rate from target atoms optically pumped with elliptically polarized light, and show how imperfect polarization effects can be measured and minimized under experimental conditions. In particular, we find that in measuring the scattering for linearly polarized light with a small circular component, the errors are proportional to the undesired circular polarization component and to $P_3$, the scattering sensitivity to circular light. We also present in detail a polarizer design which generates both linear and circular polarizations, allowing measurement of all scattering polarization sensitivities without requiring interchange of optical elements.

• Received 15 January 1999

DOI:https://doi.org/10.1103/PhysRevA.60.330