SPECTROSCOPIC CHARACTERIZATION OF LASER-ABLATED PLUME FROM A LA-CA-MN-O TARGET IN AN O-2 AMBIENT

The composition and evolution of the plume produced by the laser ablat ion of a La2O3-CaO-MnO2 target at 355 nm in an O-2 ambient have been s tudied with a temporally and spatially resolved optical emission spect roscopic technique. Besides lines of excited metal atoms and ions, suc h as La(II), Ca(II), Mn(II), Ca(I), and Mn(I), bands of the metal oxid es LaO and MnO were observed. In the oxygen ambient, two emission peak s corresponding to a fast and a slow component of ablated species Mn(I ), MnO, Ca(I), and LaO were measured by optical time-of-flight spectro scopy. The delay times of two emission components for these ablated sp ecies were investigated as a function of the observation distance from the target surface and the laser fluence. The possible mechanism of t he laser-ablated plume is discussed.