An Experimental Study of Multiphoton Ionization in Fused Silica at IR and Visible Wavelengths

We present the results of an experimental study multiphoton ionization in fused silica, using a linearly polarized femtosecond Satsuma fiber laser with active medium based on Yb+3 ions, at 515 -nm and 1030 wavelengths. The radiation transmission silica was measured as function intensity wavelength data were analyzed theoretical model Keldysh theory. determined absorption cross-sections case four- eight-photon contribution avalanche ionization. obtained provide insight into fundamental processes involved have implications for its applications, such micromachining material processing.