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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.