Two-dimensional spatial imaging based on acoustooptical deflectors

Two acoustooptical deflectors placed orthogonal to each other allow the scanning of a laser beam in two dimensions without mechanical movement. A complete scan is possible in 50 micros, providing a spatial resolution of 20 x 125 spots. This is used to follow the development of plumes generated by laser vaporization from a surface. Both Na atoms and Pb(2) dimers can be monitored by absorption over the lifetime of the plume. The use of a second channel in the transient digitizer allows normalization to correct for variations in laser intensity and deflection efficiencies during the scan. Concentration maps for each can thus be obtained.