Femtosecond laser-induced optical breakdown threshold in water

For studying the relationship between breakdown thresholds and laser parameters, numerical simulation for ellipsoidal time and space model of femtosecond laser-induced optical breakdown in water was done at different pulse duration (40 fs to 540 fs), wavelength (400 nm to 1 200 nm) and spot size (0 to 200 μm) with a Runge-Kutta method. The figures of threshold intensity as a function of pulse duration, wavelength or spot size were given via variable-controlled method. Some conclusions were presented about the relationship between threshold intensity and laser parameters. At last, the figures of threshold power, energy, radiant exposure or electric field strength as a function of pulse duration, wavelength or spot size were presented, which gives a further theoretical support for the study