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

作者：Grudtsyn, Ya, V^*; Koribut, A., V; Rogashevskii, A. A.; Gerasimova, Yu A.; Trofimov, V. A.; Yalovoi, V., I; Semjonov, S. L.

来源：LASER PHYSICS LETTERS, 2021, 18(3): 035401.

DOI：10.1088/1612-202X/abdcc0

• four-photon absorption
• plasma absorption (inverse bremsstrahlung)
• electron collision rate

Transmission versus intensity in 100 mu m 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 Schrodinger 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) sigma(k) and plasma absorption (inverse bremsstrahlung) sigma cross sections. The obtained values are sigma(4) = 2.5 x 10(-117) cm(8) s(3), sigma = 3.6 x 10(-18) cm(2) for CaF2 and sigma(4) = 4.4 x 10(-116) cm(8) s(3), sigma = 3 x 10(-18) cm(2) for UV fused silica.