LASER DAMAGE OF ALKALINE-EARTH FLUORIDES AT 248 NM AND THE INFLUENCE OF POLISHING GRADES

Citation
E. Stenzel et al., LASER DAMAGE OF ALKALINE-EARTH FLUORIDES AT 248 NM AND THE INFLUENCE OF POLISHING GRADES, Applied surface science, 110, 1997, pp. 162-167
Citations number
21
Categorie Soggetti
Physics, Condensed Matter","Chemistry Physical","Materials Science, Coatings & Films
Journal title
ISSN journal
01694332
Volume
110
Year of publication
1997
Pages
162 - 167
Database
ISI
SICI code
0169-4332(1997)110:<162:LDOAFA>2.0.ZU;2-I
Abstract
Damage behaviour and thresholds for single 248 nm/14 ns excimer laser pulses have been investigated for single crystals of CaF2 and BaF2 wit h (111) surface orientation. The probe beam deflection technique was a pplied as a sensitive tool for detecting the onset of single-shot dama ge. Below the plasma threshold, we observed one- and two-photon absorp tion for CaF2 and BaF2, respectively, When testing the influence of di fferent polishing techniques, we found the lowest thresholds for conve ntional hard-polish. Advanced methods as ductile machining or chemical polishing lead to a distinct increase in damage threshold up to and e ven better than what is observed for cleaved surfaces, SEM investigati ons of irradiated areas show that damage preferably takes place at res idual steps or other structural defects.