Two-photon absorption properties of commercial fused silica and germanosilicate glass at 264 nm

Using high-intensity femtosecond pulses at λ=264 nm, we have measured the two-photon absorption (TPA) coefficient in three fused silica samples Suprasil, Herasil, Infrasil (Heraeus) and in 3.5 mol % Ge-doped fused silica. While in fused silica samples the TPA coefficient value is about 2×10−11 cm/W, in germanosilicate glass it equals (42±3)×10−11 cm/W.