Polarization storage by nonlinear orientational hole burning in azo dye-containing polymer films

We present experimental evidence of polarization storage by nonlinear orientational hole burning in films of poly(methylmethacrylate) containing disperse red one (DR1). The data are written by polarized nonlinear excitation of DR1 by a tightly focused Ti: Sapphire laser and read by polarized confocal laser scanning microscopy in the reflection mode. The bits that are imaged with a light polarization which is parallel to the excitation laser polarization reflect light ∼2.5 times more efficiently than those which are imaged with a light polarization which is perpendicular to it. This finding is consistent with orientational hole burning of chromophores by two-photon excitation.