Laser assisted free-free scattering with variable laser polarization within the scattering plane

In previous work we reported one-photon emission experiments that examine electron-helium scattering in the presence of an Nd:YAG laser field of 1.17 eV photons, where the laser polarization direction was varied within a plane perpendicular to the scattering plane, and intersecting it along the momentum-transfer direction.\footnote{B.A. deHarak, B.Nosarzewski, M. Siavashpouri, N.L.S. Martin, Phys. Rev. A {\bf90}, 032709 (2014)} The results were perfectly consistent with the Kroll-Watson\footnote{N. M. Kroll and K. M. Watson, Phys. Rev. A 8, 804 (1973)} approximation. In particular there was no evidence of free-free transitions when the polarization was perpendicular to the momentum-transfer direction, in contrast to the experiments of Wallbank and Holmes.\footnote{M. O. Musa, A. MacDonald, L. Tidswell, J. Holmes, and B. Wallbank, J. Phys. B, 43 (17):175201, 2010} We are in the process of reconfiguring our apparatus to more closely mimic their experiments where the laser polarization was varied {\it within} the scattering plane for one-, two-, and three-photon absorption. Our preliminary results will be presented.