Femtosecond multiphoton excitation of the luminescence of impurity ions in crystals

The mechanism of excitation of the impurity luminescence in crystalline materials under intense femtosecond laser irradiation has been investigated. It is established that a high concentration of band electrons and holes, which are successively captured by impurity ions, is formed during the femtosecond three-photon ionization of the intrinsic crystalline material. The efficiency of electron–hole excitation of the impurity composition in crystals (as for the electron beam irradiation) is determined by the degree of difference between the electron systems of the $s$, $p$, and $d$ subgroups of the outer shell of cations of the intrinsic material and activator.