Analysis on the damage threshold of MgO:LiNbO3 crystals under multiple femtosecond laser pulses

Abstract

An improved theoretical model of the interaction between multiple femtosecond laser pulses and MgO:LiNbO3 crystals with different doping concentrations has been established based on the classical two-temperature model. The evolutions of electron and lattice temperature with the duration, the repetition frequency and the numbers of multiple femtosecond laser pulses in MgO:LiNbO3 crystals have been simulated numerically by the Crank-Nicholson implicit finite-difference method. Furthermore, the variations of the damage threshold of MgO:LiNbO3 crystals with the parameters of multiple femtosecond laser pulses at different doping concentrations, as well as the influence of doping concentration on damage threshold have also been analyzed. The results show that, the damage threshold of MgO:LiNbO3 crystals increases with the increasing of the duration of the femtosecond laser pulse. The damage threshold of MgO:LiNbO3 crystals first decreases with the increasing of the numbers and the pulse repetition frequency of the laser pulses and then tends to be a constant. The damage threshold of a small amount of MgO-doped LiNbO3 crystals is higher than that of undoped LiNbO3 crystals. Consequently, the resist damage capability of LiNbO3 crystals can be enhanced by doping appropriate MgO in many practical applications.