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Femtosecond pulse laser ablation of metallic, semiconducting, ceramic, and biological materials

  • Production of holes and grooves of < 30 micrometers diameter with high aspect ratio value is a delicate task either for mechanical tools, or for conventional nanosecond pulse lasers like e.g. pulsed Nd:YAG or excimer lasers. They later tend to cause microcracks extending from an annular melting zone, or substantial disruption, respectively. Experimental results are presented which demonstrate that the development of intense ultrashort pulse laser systems (>> 1012 W cm-2, (tau) < 1 ps) opens up possibilities for materials processing by cold plasma generation and ablation of metals, semiconductors, ceramics, composites, and biological materials. A femtosecond and a nanosecond dye laser with pulse durations of 300 fs (< 200 (mu) J) and 7 ns (< 10 mJ), and center wavelengths at 612 and 600 nm, respectively, both focused on an area of the order of 10-5 cm2, have been applied either to absorbing substrates, like polycrystalline gold, silicon (111), aluminum nitride ceramics, or transparentProduction of holes and grooves of < 30 micrometers diameter with high aspect ratio value is a delicate task either for mechanical tools, or for conventional nanosecond pulse lasers like e.g. pulsed Nd:YAG or excimer lasers. They later tend to cause microcracks extending from an annular melting zone, or substantial disruption, respectively. Experimental results are presented which demonstrate that the development of intense ultrashort pulse laser systems (>> 1012 W cm-2, (tau) < 1 ps) opens up possibilities for materials processing by cold plasma generation and ablation of metals, semiconductors, ceramics, composites, and biological materials. A femtosecond and a nanosecond dye laser with pulse durations of 300 fs (< 200 (mu) J) and 7 ns (< 10 mJ), and center wavelengths at 612 and 600 nm, respectively, both focused on an area of the order of 10-5 cm2, have been applied either to absorbing substrates, like polycrystalline gold, silicon (111), aluminum nitride ceramics, or transparent materials, like synthetic and human dental hydroxyapatite composites, bone material, and human cornea transplants. The fs-laser generates its own absorption in transparent materials by a multiphoton absorption process, and thus forces the absorption of visible radiation. Because the time is too short (< ps) for significant transport of mass and energy, the beam interaction generally results in the formation of a thin plasma layer of approximately solid state density. Only after the end of the subpicosecond laser pulse, it expands rapidly away from the surface without any light absorption and further plasma heating. Therefore, energy transfer (heat and impulse) to the target material, and thermal and mechanical disruption are minimized. In contrast to heat- affected zones (HAZ's) generated by conventional nanosecond pulse lasers of the order of 1 - 10 micrometers , HAZ's of less than 0.02 micrometers were observed.zeige mehrzeige weniger

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Metadaten
Autor*innen:Wolfgang Kautek, Jörg KrügerORCiD
Persönliche Herausgeber*innen:E. Beyer
Dokumenttyp:Beitrag zu einem Sammelband
Veröffentlichungsform:Verlagsliteratur
Sprache:Englisch
Titel des übergeordneten Werkes (Englisch):Laser materials processing
Jahr der Erstveröffentlichung:1994
Herausgeber (Institution):Europäische Gemeinschaften / Generaldirektion Wissenschaft, Forschung und Entwicklung
Verlag:SPIE--the International Society for Optical Engineering
Verlagsort:Bellingham, Wash.
Ausgabe/Heft:2207
Erste Seite:600
Letzte Seite:611
Veranstaltung:Conference on Production Line Processes ; Conference on Process Control and Modeling ; Conference on Novel Applications
Veranstaltungsort:Vienna, Austria
Beginndatum der Veranstaltung:1994-04-05
Enddatum der Veranstaltung:1994-04-08
DOI:10.1117/12.184768
ISSN:1605-7422
ISBN:0-8194-1508-1
Bemerkung:
Serientitel: SPIE proceedings series – Series title: SPIE proceedings series
Verfügbarkeit des Dokuments:Physisches Exemplar in der Bibliothek der BAM vorhanden ("Hardcopy Access")
Bibliotheksstandort:Sonderstandort: Publica-Schrank
Bibliotheksstandort:Gg 222
Datum der Freischaltung:19.02.2016
Referierte Publikation:Nein
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