A novel technique for measuring the polarization light scattering func
tion of surfaces using a Mueller matrix imaging scatter polarimeter is
presented. This technique measures the near-specular scatter of refle
ctive surfaces as Mueller matrix images, enabling the diattenuation, r
etardance, and depolarization of the scattered light to be determined.
An example of measurements of a diamond-turned aluminum mirror with a
n rms roughness of 11.4 nm is presented and interpreted. The most surp
rising result in our data was that this scattering process created par
tially elliptical polarized light from unpolarized incident light, whe
re we had expected essentially partially linearly polarized light.