Yb,Na:CaSrF2 - A promising laser crystal medium in UV - VIS - Near-IR domain

The crystal CaF₂ and its isotypes SrF₂ and BaF₂ doped with lanthanide elements, they are investigated for nonlinear optical applications and generation of ultrashort laser pulses. The Yb-doped crystal fluoride matrixes are could be also attractive for ICT, medical interventions, laser materials treatment, etc. The broad near-IR (NIR) luminescence in Yb³⁺ state (the second telecommunication window) and also their yellow-green and near-UV luminescence of Yb²⁺ are observed at low temperatures, although for the Yb,Na:CaSrF₂ it is clearly observable at normal conditions. The Stokes fluorescence bands between 300 - 400 nm for the Yb,Na:CaSrF₂ crystal medium induced from non-parametric processes in UV are narrow, clearly distinguishable and could be applied for novel lasers in UV - VIS range.