COHERENT 4-WAVE-MIXING IN A LASER-PREPRODUCED PLASMA - OPTICAL FREQUENCY-CONVERSION AND 2-DIMENSIONAL MAPPING OF ATOMS AND IONS

We discuss applications of coherent four-wave mixing in the plasma of optical breakdown produced by an additional laser pulse (laser-preprod uced plasma) for the generation of short-wavelength radiation and the investigation of spatial distribution of atoms and ions. The use of an additional laser for the generation of laser-produced plasma on the s urface of a metal target makes it possible to optimize the efficiency of frequency conversion and to implement plasma diagnostics at various stages of plasma expansion. An experimental technique based on hyper- Raman-resonant four-wave mixing is developed for two-dimensional mappi ng of relative populations of excited atomic and ionic states in laser -produced plasma.