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.