Consequences of combining laser irradiation with other stimuli on laser desorption and ablation from wide bandgap insulators

dWhen a transparent, wide bandgap insulator is exposed to sub-bandgap laser irradiation, defects at and near the surface often dominate the response i n terms of particle emission and eventual ablation of material. We explored the consequences of applying a variety of stimuli that can generate defect s on single crystal surfaces of inorganic ionic crystals. The stimuli inclu de: electron beam irradiation, a second laser beam, mechanical treatment, a nd thermal treatment. We found that a common theme evolves where these stim uli generate sites for strong interactions of the probing laser beam, leadi ng to a dramatic decrease in the laser intensities needed for ejection of i ons, neutrals, and eventual plume formation. (C) 2000 Elsevier Science B.V. All rights reserved.