Electron-beam-induced absorption of ArF, KrF, and XeF laser radiation in optical materials

Measurements were made of the absorption of laser radiation at the wavelengths of 193, 248, and 353 nm in optical materials at the moment of action of an electron beam. The dependence of the optical density of a material on the power density of the electron beam was linear. The coefficient of proportionality κ in this dependence was a parameter of the material and it was governed by the properties of short-lived colour centres. The value of κ was determined for MgF₂, CaF₂, BaF₂, and Al₂O₃ crystals, as well as for quartz glasses. In the case of MgF₂ the parameter was κ = 29 ± 6, 150 ± 20, and 14 ± 6 cm² GW^-1 at λ = 193, 248, and 353 nm, respectively. For CaF₂ and BaF₂ its value was κ ≈ 100 cm² GW^-1. Amplification was observed in Al₂O₃ at λ = 193 and 248 nm: in this case κ was negative: –2.0 and –0.5 cm² GW^-1, respectively.