Laser Induced shock propagation in bulk Transparent glass media

High energy laser pulses are replacing the traditional hammers, shock tubes and gas guns to induce impulses that are sufficient to compress the medium to extreme states by launching shockwaves capable of inducing phase transitions in the medium. We present the shockwave evolution during ns laser pulse interaction with a transparent BK-7 glass of dimensions 50 mm × 50 mm × 15 mm. The input laser pulse energies were varied over 500 to 2000 mJ resulting in intensities of 20 – 100 GW/cm². Due to the transparent nature of the BK-7, two different shockwaves one from the interface and the other from self-focused damage track within the bulk of the medium were observed. The shockwaves from the interface propagated along the laser propagation (longitudinal) direction with a velocity of 6.38 – 6.91 km/s. While the shockwaves from the self-focused damage track travelled in the transverse direction. With increasing laser pulse energy, an interesting exchange between the longitudinal and transverse shockwaves is observed.