Scattering of laser radiation under conditions of optical breakdown of transparent dielectrics and gases

An investigation was made of the scattering of radiation from a single-frequency neodymium laser when optical breakdown took place in transparent dielectrics and gases. A scattering peak with a preferential forward direction was observed in ~100 psec from the breakdown. This peak was due to the reflection by the boundary of a plasma cloud which always appeared at the center of the caustic of the focusing objective. It was demonstrated that the main stage of the optical breakdown developed in a time of ~100 psec.