TEMPORAL AND SPATIAL EVOLUTION OF LASER-ABLATED PLASMA FROM YBA2CU3O7

YBa2Cu3O7 target was laser ablated, and the time-of-flight (TOF) distr ibutions of Y, Y+, and YO in the resultant plasma were investigated as functions of distance from the target and laser energy density using emission spectroscopy. Up to a short distance from the target (congrue nt-to 1.5 cm), TOF distributions show twin peaks for Y and YO, while o nly single-peak distribution is observed for Y+. At greater distances (>1.5 cm) all of them exhibit single-peak distribution. The twin peaks are assigned to species corresponding to those generated directly/in the vicinity of target surface and to those generated from collisional /recombination process.