Anomalous small-angle X-ray scattering of a femtosecond irradiated germano silicate fibre preform

The photoinscription of standard telecommunications glass materials by femtosecond radiation is shown to induce significant mesoscopic structure. The scattering intensity for irradiated glasses is close to two orders of magnitude greater than that of unexposed material. Anomalous small-angle X-ray scattering (ASAXS) around the germanium K-edge for the silica and germanium doped silica regions of a fibre preform is used to demonstrate that identical structures are induced in both glass materials, with germanium displaying a capacity to isomorphically replace silicon in the case of the germanium doped silica. Analysis of measured scattering indicates that photo-inscribed features are produced at two distinct scales with typical radii of R ≈ 20 Å and Rmin ≈ 200 Å.