Abstract
Laser-induced breakdown of colloidal suspensions, such as polystyrene, <TEX>$ZrO_2$</TEX>, and <TEX>$SiO_2$</TEX> particles in diameters of 100-400 nm in water is investigated by nanosecond flash-pumped Nd:YAG laser pulses operating at a wavelength <TEX>${\lambda}$</TEX>= 532 nm. The breakdown threshold intensity is examined in terms of breakdown probability as a function of laser pulse energy. The threshold intensity for <TEX>$SiO_2$</TEX> particles (<TEX>$1.27{\times}10^{11}\;W/cm^2$</TEX>) with a size of 100 nm is higher than those for polystyrene and <TEX>$ZrO_2$</TEX> particles with the same size, namely <TEX>$5.7{\times}10^{10}$</TEX> and <TEX>$5.5{\times}10^{10}\;W/cm^2$</TEX>, respectively. Results indicate that the absorption of five photons is required to induce ionization of <TEX>$SiO_2$</TEX> particles, whereas the other particles necessitate four-photon absorption. These breakdown thresholds are compared with those measured by nanosecond pulses from a diode-pumped Nd:YAG laser having a different focusing geometry.
© 2007 Optical Society of Korea
PDF Article
More Like This
Cited By
Optica participates in Crossref's Cited-By Linking service. Citing articles from Optica Publishing Group journals and other participating publishers are listed here.