Influence of erbium doping on the femtosecond laser damage characteristics of fluorozirconate glasses

Abstract

In this study, we systematically investigated femtosecond laser-induced damage characteristics of ZHBLAN (27ZrF4–25HfF4–10BaF2–5SrF2–5CaF2–4LaF3–14AlF3–10NaF), and the impact of Er3+ doping on the optical characteristics and damage characteristics of the matrix material. The glasses were subjected to a comparative analysis with respect to typical ZBLAN glasses. The sizes and morphology of damaged craters changed with the power of the 800 nm femtosecond laser. The samples were analyzed using digital and scanning electron microscopes, and their femtosecond laser-induced damage thresholds (LIDTs) were calculated by linear regression. The LIDTs decreased obviously from 612 mJ/cm2 to 532 mJ/cm2 after Er3+ was doped into the ZHBLAN glass. This is related to the absorption of Er3+ near the wavelength of the femtosecond laser and the change in the bandgap structure of the glass due to Er3+ doping. In addition, we have analyzed the electron convergence rate within the material during laser irradiation. The combination of physical models and simulation results reveals the association between the ionization rate of optical materials and the laser damage threshold.