Modulating the nonlinear refractive index through F/O ratio to reduce the self-focusing effect of fluorophosphate glasses

In this study, we systematically investigated the relationship between the F/O ratio and the nonlinear refractive index of fluorophosphate glass, revealing that the nonlinear refractive index decreased exponentially as the F/O ratio increased. A formula for calculating the nonlinear refractive index based on the composition of fluorophosphate glasses was proposed. Since the nonlinear refractive index is directly related to self-focusing damage, we demonstrated through femtosecond laser-induced damage experiments that the F/O ratio can effectively modulate the self-focusing damage properties of fluorophosphate glass. Additionally, time-resolved pump-probe experiments were employed to capture the damage process and explore the damage mechanisms.