Imaging and spectral analysis of hydroxyapatite laser ablation plumes

The images obtained during KrF excimer laser ablation of HA targets have shown the presence of two different glow regions in the plume. The first one, plume-like shaped, expands at a velocity of about 2.0 x 10(4) m/s. The second one, which looks like a small plasma cloud close to the target surface, shows an expansion velocity of about 2.9 x 10(3) m/s. The spectroscopic analysis of the plume has revealed the presence of several atomic (CaI, PI, OI, and impurities), ionic (CaII) and molecular (calcium oxides) species in the plasma. The dynamics of the main atomic and ionic species has been analysed from the spectra. CCD-images recorded through diverse bandpass filters have been used to map the species distribution along the plume and, thus, to identify the nature of the previously observed glow regions. Pictures obtained by this method have revealed the atomic nature of the first glow region while the second one has been found to be mainly constituted by molecular radicals. (C) 1998 Elsevier Science B.V.