Polarization measurements of two He I transitions using beam-tilted-foil excitation

The Stokes parameters of light emitted following beam-foil excitation have been measured as a function of foil tilt angle from 00 to 800, in 5 degree increments, for the 2s 1S - 3p 1p0 and 2p 1p0 - 4d 1D transitions in He I. The curves so obtained are remarkably different for the two transitions. These measurements are an extension of a recently completed experiment which demonstrated the close agreement betwen the polarization parameters from the 2s - 3p and 2s - 4p transitions and between those from the 2p - 3d and 2p - 4d transitions