ArF laser induced pulse absorption in fused silica (type III): Modeling the fluence and repetition rate dependence

At 193 nm, weak stationary bulk absorption coefficients αstat in standard and experimental grade fused silica (type III) are measured in dependence on the laser fluence H and repetition rate f. The samples show non-linear increases αstat(H) for 0.2 ⩽ H ⩽ 5 mJ cm−2 pulse−1 (f = const.) and αstat(f) for 100 ⩽ f ⩽ 1000 Hz (H = const.). An absorption model, focussing on ArF laser induced E′ center generation and annealing, and the associated rate equations are applied to simulate the experimental data quantitatively. From the simulations, material parameters like the 2-photon absorption (TPA) coefficient, the E′ center absorption cross section σE′ and the hydrogen related E′ annealing rate are calculated. TPA coefficients values of 9.7 · 10−9 cm/W (standard grade material) and 1.4 · 10−8 cm/W (experimental grade material), E′ center cross sections of 4.5 · 10−18 and 3.6 · 10−18 cm2 and hydrogen annealing rates of 1.5 s−1 (standard grade) and 3.4 s−1 (experimental grade) are found.