Three Dimensional Laser Induced Blow-off Simulation Studies from 20 µm Thick Aluminum Foil

Nanosecond laser induced material blow-off from the rear side of 20 µm thick aluminum foil confined with a glass substrate is performed using the three-dimensional (3D) and three temperature FLASH radiation hydrodynamic code. The material blow-off is induced by irradiating 10 ns, 532 nm, and 25 - 200 mJ (2 – 10 GW/cm²) laser energy pulses at the glass-foil interface. Due to the spatial confinement of the foil, high pressure, specific energy, and temperature build-up at the interface resulting in the material blow-off from the rear side of the foil, along the laser propagation direction. The hydrodynamics of the blow-off material in the form of plasma and shock wave expanding in ambient air is affected by the input laser conditions and the substrate used. In this work, we present the three-dimensional analysis of the hydrodynamics of laser induced blow-off (LIBO) plasma and shock waves expanding in ambient atmospheric air. The simulations were performed for different input laser energies to understand the effect of energy on LIBO parameters such as shock velocity, plasma pressure, temperature, and energy. The simulated blow-off shock expansion is correlated with the experimental results to understand the underlying physics of the blow-off process.