Mikroskopie

At 193 nm, weak stationary bulk absorption coefficients astat 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 astat(H) for 0.2 6 H 65mJ cm_2 pulse_1 (f = const.) and astat(f) for 100 6 f 6 1000 Hz (H = const.). An absorption model, focussing on ArF laser induced E0 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 E0 center absorption cross section rE0 and the hydrogen related E0 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), E0 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.