Depolarization effects from nanoimprinted grating structures as measured by Mueller matrix polarimetry

Mueller matrix polarimetry (MMP) is introduced to characterize nanoimprinted grating structures, and noticeable depolarization effects from measured data are observed. We demonstrate that these depolarization effects are mainly induced by the finite bandwidth and numerical aperture of the instrument, as well as the residual layer thickness variation of the measured sample. After incorporating the depolarization effects into the optical model, not only improved accuracy can be achieved for the line width, line height, and residual layer thickness measurement but also the residual layer thickness variation over the illumination spot can be directly determined by MMP. (C) 2013 AIP Publishing LLC.