6533b7d3fe1ef96bd1260054
RESEARCH PRODUCT
Bleaching of optical activity induced by UV Laser exposure in natural silica
Fabrizio MessinaMarco Cannassubject
Condensed Matter - Materials ScienceChemistryAnalytical chemistryMaterials Science (cond-mat.mtrl-sci)FOS: Physical sciencesDisordered Systems and Neural Networks (cond-mat.dis-nn)TrappingCondensed Matter - Disordered Systems and Neural NetworksCondensed Matter PhysicsLaseroptical fibers radiation effects radiation-induced attenuationElectronic Optical and Magnetic Materialslaw.inventionParamagnetismlawAbsorption bandAtomMaterials ChemistryCeramics and CompositesUv laserIrradiationUltraviolet radiationdescription
We report experimental data on two types of natural silica, differing for 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 5.12eV and of the associated emissions at 3.14eV and 4.28eV, 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.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2004-01-01 |