Laser induced damage studies in borosilicate glass using nanosecond and sub nanosecond pulses

Abstract

The damage mechanism induced by laser pulse of different duration in borosilicate glass widely used for making confinement geometry targets which are important for laser driven shock multiplication and elongation of pressure pulse, is studied. We measured the front and rear surface damage threshold of borosilicate glass and their dependency on laser parameters. In this paper, we also study the thermal effects on the damage diameters, generated at the time of plasma formation. These induced damage width, geometries and microstructure changes are measured and analyzed with optical microscope, scanning electron microscope and Raman spectroscopy. The results show that at low energies symmetrical damages are found and these damage width increases nonlinearly with laser intensity. The emitted optical spectrum during the process of breakdown is also investigated and is used for the characterization of emitted plasma such as plasma temperature and free electron density. Optical emission lines from Si I at 500 nm, Si II at 385nm and Si III at 455 nm are taken for the temperature calculations.

Time‐resolved Raman spectroscopy of polystyrene under laser driven shock compression

“…In these relations, U s and u p are the shock and the particle velocities. A correlation between average shock pressure and incident laser intensity using hydrodynamic simulation was earlier established . The wavenumber shifts of the various Raman active modes of aPS as a function of shock pressure were also measured.…”

“…A correlation between average shock pressure and incident laser intensity using hydrodynamic simulation was earlier established. [38] The wavenumber shifts of the various Raman active modes of aPS as a function of shock pressure were also measured. The wavenumber shift data were analyzed to determine mode Grüneisen parameter and bond anharmonicities.…”

“…Experiments were performed on a confinement geometry target assembly which consisted of a cover float glass (100 × 100 × 5 mm 3 ), an aluminum foil (50 μm thick) for shock generation, followed by the polystyrene target (200 μm thick) and a backup float glass (100 × 100 × 5 mm 3 ). Target was mounted on the motorized X–Y–Z stage, which was synchronized with the laser system to get each shot on fresh target.…”

Raman spectroscopy of poly (methyl methacrylate) under laser shock and static compression

“…The experiments were performed on confined geometry target assembly by pump and probe technique using high power pulsed laser. [29,30] The target assembly consists of a cover glass (100 × 100 × 5 mm 3 ), a PMMA sheet (100 mm × 100 mm × 200 μm thick), an aluminium foil (100 mm × 100 mm × 50 μm thick) and a backup glass (100 × 100 × 5 mm 3 ). This target assembly was mounted on a motorized X-Y-Z translational stage.…”

In situ Raman spectroscopic studies of polyvinyl toluene under laser‐driven shock compression and comparison with hydrostatic experiments

“…All experiments were performed on confined geometry target assembly targets by pump‐probe technique using nanosecond‐pulsed lasers. The fundamental laser pulse having power density ~10 9 W/cm 2 was used for shock generation and was focused on the aluminum foil with a spot diameter of 2 mm.…”