Effects of H2 impregnation on excimer-laser-induced oxygen-deficient center formation in synthetic SiO2 glass

Abstract

We examined the effect of H2 impregnation on defect formation upon F2 laser (7.9 eV) and ArF excimer laser (6.4 eV) irradiation. It was revealed that H2 impregnation enhanced the formation of oxygen-deficient center (Si–Si bond) as well as suppressed the formation of E′ center and nonbridging oxygen hole center. A Si–Si bond gives an intense absorption band peaking at 7.6 eV, which contributes the absorption at the wavelength of F2 laser light. These results indicate that H2-free SiO2 glass, which is clearly inappropriate for KrF and ArF excimer laser optics, is more suitable for F2 laser optics than H2-impregnated glass.

Role of hydrogen loading and glass composition on the defects generated by the femtosecond laser writing process of fiber Bragg gratings

“…In the case of all-silica fiber, gratings can be produced with ArF radiation at 193 nm [13] rather than with 248 nm KrF laser light typically used for Ge-doped fibers. Defect formation after exposure to 193 nm, or even shorter wavelength 157 nm light from a F 2 laser, has been studied primarily in bulk silica glasses, both with and without hydrogen loading [14,17,18]. The results are very similar to what we observe in our studies, i.e.…”

Defects in oxide glasses

“…This treatment usually increases radiation toughness, e.g., against KrF laser (5.0 eV) irradiation [64]. However, it was found that under irradiation by ArF or F 2 laser photons, H 2 loading indeed helps to suppress the creation of dangling bonds, but at a price of much enhanced generation of oxygen vacancies [24]. The suggested mechanism of this phenomenon is the stabilization of radiation-created oxygen interstitials by transforming them to silanol bonds.…”

“…The 7.6 eV absorption band is important to vacuum UV applications of silica. It is efficiently created by ArF or F 2 excimer laser photons in the presence of interstitial H 2 [24]. Presently the assignment of neutral O vacancy is widely accepted, however, it is also argued that more complex defect structures could be involved [25].…”

Modification of vacuum-ultraviolet absorption of SiOH groups in SiO2 glass with temperature, F2 laser irradiation, and H–D isotope exchange

“…It was first loaded with H 2 ($2.5 atm) for 10 h at 500°C to suppress the formation of the silicon and oxygen dangling bonds (E 0 and non-bridging oxygen hole centers, respectively) whose absorption bands ($4-8 eV) interfere with the measurements of VUV absorption band of SiOH groups [7,8]. The sample was then exposed to 7.2 · 10 4 pulses of F 2 laser light (LPF-210, Lambda Physik, hm = 7.9 eV, $6 mJ cm À2 pulse À1 , pulse duration $20 ns) at room temperature, followed by isochronal annealings (10 min) from 100 to 800°C in 100°C steps.…”