Luminescence of α-quartz crystal and silica glass under excitation of excimer lasers ArF (193 nm), KrF (248 nm)

Luminescence of crystalline α-quartz and silica glass was studied under focused laser excitation. It was found that in crystalline α-quartz the luminescence of self-trapped exciton (STE) is excited in two-photon regime with ArF (193 nm) excimer laser. In the case of KrF (248 nm) laser excitation mainly luminescence related to near surface area is seen even without laser beam focusing. The near surface luminescence has an emission band similar to that of STE in bulk. Temperature quenching is also similar, therefore this luminescence is attributed to STE created in the area of surface. Luminescence decay kinetic of surface STE is longer than bulk STE decay (tens of ms compared to 1 ms at 80 K). Electron or/and hole self-trapping near the surface is assumed. Their recombination could provide longer duration of surface STE luminescence. Similar surface luminescence was not excited with ArF (193 nm) excimer laser. The nature of absorption for laser 248 nm photons at surface is not yet clear. Luminescence of silica glass of III type excited with focused beam of KrF (248 nm) laser resembles that of previously studied luminescence of STE in silica.