Anisotropic luminescence photo-excitation in H2-loaded Ge-doped silica exposed to polarized 193Â nm laser light

We have investigated the polarization dependence of the photo-luminescence VUV excitation spectra in H2-loaded Ge-doped SiO2 glass exposed to polarized 193 nm laser light. As for non-H2-loaded Ge-doped silica, we show that the β band photo-luminescence excited in the VUV spectral range (6-9 eV) remains positively polarized. In our experiments, the polarization degree P is quite high (P ≈ 0.4) due to the preferential bleaching of polarized UV-exposure. As a result, we observe a highly anisotropic luminescence photo-excitation since the luminescence is mainly polarized in the writing laser polarization direction.