Polarization fraction measured for olivine dust samples with particle SDs characterized by different effective radii (a_eff), shown as a function of scattering angle. For comparison, a Rayleigh scattering polarization fraction function with a maximum polarization p_max of 9% is overplotted (blue solid line). Measurements for samples with a_eff = 2.6 μm (blue circles) and a_eff = 3.8 μm (red diamonds) were obtained using a laser source at 633 nm. Data for the sample with a_eff > 20 μm (yellow crosses) were acquired using a white light source and camera systems with a spectral response in the 1.5–1.6 μm range.