SPATIAL-MAPPING OF TRANSIENT ATOMIC CONCENTRATIONS USING ACOUSTOOPTIC DEFLECTION

We report a new imaging system for obtaining spatially and temporally resolved atomic absorption profiles for transient events. This is based on an acousto-optic beam deflector that scans the probe laser beam in one dimension repeatedly across the spatial region of interest. Scan rates of 10 mu s durations essentially freeze the absorbing species in time to allow a spatial resolution of 0. 06 cm over a 1. 2 cm length. With the use of 2K of buffer memory and a digitization interval of 200 ns (12 bits), the time evolution can be followed up to a total of 400 mu s. The capabilities are demonstrated in the study of atom formation in a laser-generated plume from a sodium tungstate surface.