Bleaching of optical activity induced by UV laser exposure in natural silica
- Autori: Cannas, M.; Messina, F.
- Anno di pubblicazione: 2004
- Tipologia: Abstract in rivista (Abstract in rivista)
- OA Link: http://hdl.handle.net/10447/7152
We report experimental data on two types of natural silica, differing in their OH content, irradiated with UV photons (4.66 eV) from a pulsed Nd:YAG laser. Irradiation induces a reduction of the absorption band at 5.12 eV and of the associated emissions at 3.14 eV and 4.28 eV, ascribed to twofold coordinated Ge(@Ge) centers pre-existing in our samples. The bleaching is mainly due to the post-irradiation conversion of @Ge into the paramagnetic H(II) center via trapping of a H atom. Comparison with literature data points out the peculiarities of silica with a low Ge concentration as regards UV-induced transformations.