Multiphoton and plasma absorption measurements in CaF2 and UV fused silica at 473 nm

Transmission versus intensity in 100 μm CaF2 and UV fused silica samples at a wavelength of 473 nm for different durations of the initial pulse was studied. Fitting the experimental data with a model based on the solution of the nonlinear Schrödinger equation and taking into account multiphoton absorption and absorption by the plasma, as well as the Kerr nonlinearity, diffraction and dispersion of the medium, made it possible to obtain the values of multiphoton (k-number of photons) σk and plasma absorption (inverse bremsstrahlung) σ cross sections. The obtained values are σ4 = 2.5 × 10−117 cm8 s3, σ = 3.6 × 10−18 cm2 for CaF2 and σ4 = 4.4 × 10−116 cm8 s3, σ = 3 × 10−18 cm2 for UV fused silica.