3-Dimensional simulation and footprint of optical breakdown in dielectrics induced by femtosecond laser pulse

In this paper dynamics of optical breakdown process in dielectrics induced by femtosecond laser pulses have been simulated numerically. Using rate equations, the dynamics of free electron density in the focusing region during a few laser pulse duration time was studied numerically. Sources of free electron production as well as sinks of electron reduction in the interacting region were considered in the calculations. In the simulation, the propagation of the laser beam through the focusing volume was also taken into account and the footprint of the breakdown process (as an estimation for medium bulk damage) was simulated 3-dimensionally. The temporal and spatial evolution of free electron density has been used for simulating the 3-dimensional footprint of optical breakdown region. The results show that the dynamics of the breakdown footprint (and volume) strongly depends on the laser and medium characteristics.

► Dynamics of optical breakdown in fused silica induced by fs laser was simulated numerically.
► 3-D footprint of generated free electrons as an estimation for bulk damage was evaluated.
► Propagation of the laser beam through the focusing volume was considered.
► Formation of asymmetrical breakdown volume at early times but shifts to symmetrical form later.
► Breakdown volume rises with time and reaches to saturated value