Laser-Solid Interactions: Localization of Momentum and of Energy

Abstract

ABSTRACTMechanisms are discussed by which sufficient momentum and energy may be localized on individual atoms, ions or molecules to account for photoablation in different regimes. In order of increasing excitation intensity, these include the roles of: “recoilless emission” (as in Bragg scattering and the Mössbauer effect) during Auger recombination of a core exciton, particularly in the Knotek-Feibelman effect; the metastable binding of multiple holes earlier proposed by Feibelman, particularly in the data of Itoh and coworkers; the change in the equilibrium interatomic spacing concomitant with excitation of a Frenkel exciton (localized broken bond), particularly in the ablative photodecomposition reported by Srinivasan and co-workers; the interaction of virtual excitons with real excitons in a strongly polarized solid, e.g. one subject to laser annealing pulses; and the interaction of ions with surface plasmons, particularly in the laser sputtering data of Hanabusa et al. A connection is made to rapid annealing and to sub-threshold defect formation. Further support is noted for the bose condensation model of pulsed laser annealing.