LASER INDUCED UNDERWATER SPARKS

Abstract

Measurements have been taken of the radiative flux density, the spectrum, and the temporal behavior of laser induced underwater sparks. When a 30-MW Q-switched ruby laser was focused into water, the resulting spark revealed a blackbody-like spectrum with a temperature of 15 000°K. The spark was delayed in time by 15 nsec with respect to the laser pulse and had a temporal behavior very similar to the laser pulse producing it.