Measurement and characterization of nanosecond laser driven shockwaves utilizing photon Doppler velocimetry

Abstract

Laser driven shockwaves from nanosecond pulsed lasers were evaluated for pressure magnitude and duration using photon Doppler velocimetry (PDV). Specific investigations were performed on Ti-6Al-4V alloys and 7085-T7651 aluminum alloys with laser full-width half-max pulse lengths ranging from 6 to 20 ns and laser intensities of 2–10 GW/cm2. The rear surface velocity data obtained using a heterodyne PDV system and an automated signal processing algorithm are demonstrated and utilized to capture rear surface velocity profiles. Peak shockwave pressures measured under bare surface water confinement reached approximately 6 GPa. Shockwave loading durations were observed to correspond with laser pulse durations with impulse loading times on the order of 2×–4× the laser pulse duration.