Dokument-ID Dokumenttyp Autoren/innen Persönliche Herausgeber/innen Haupttitel Abstract Auflage Verlagsort Verlag Herausgeber (Institution) Erscheinungsjahr Titel des übergeordneten Werkes Jahrgang/Band ISBN Veranstaltung Veranstaltungsort Beginndatum der Veranstaltung Enddatum der Veranstaltung Ausgabe/Heft Erste Seite Letzte Seite URN DOI Lizenz Datum der Freischaltung OPUS4-967 Beitrag zu einem Sammelband Bonse, Jörn; Baudach, Steffen; Krüger, Jörg; Kautek, Wolfgang Phipps, C. Femtosecond laser micromachining of technical materials Micromachining experiments were performed with Ti:sapphire laser pulses (130 fs - 150 fs, 800 nm, approximately 10 Hz) in air. Employing the direct focusing technique, highly absorbing titanium nitride (TiN) and weakly absorbing polyimide (PI) and polymethylmethacrylate (PMMA) served as target materials. The lateral and vertical precision of the laser ablation and morphological features were characterized by scanning force (SFM), scanning electron (SEM) and optical microscopy. For TiN, incubation can be observed, i.e. the single-pulse surface damage threshold (0.26 J/cm2) is by a factor of two greater than the threshold for 100 pulses. Ablation rates below 10 nm per pulse can be achieved. The evolution of sub-wavelength ripples is presented in dependence on pulse number and laser fluence, respectively. The incubation behavior of the polymers can be described by an accumulation model as for TiN. Experiments on PI with varying focal lengths result in the same modification thresholds. Different polarization states of light (linear, circular) lead to a variation of the ablation rate and to various morphological patterns in the ablation craters (wavelength ripples, cones). Swelling of PMMA occurred at fluences below the ablation threshold. Bellingham, Wash. SPIE 2000 High-power laser ablation III 0-8194-3700-X 3rd SPIE's International Conference on High-Power Laser Ablation Santa Fe, NM, USA 24.04.2000 28.04.2000 4065 161 172 10.1117/12.407346 2016-02-19 OPUS4-780 Zeitschriftenartikel Baudach, Steffen; Bonse, Jörn; Kautek, Wolfgang Ablation experiments on polyimide with femtosecond laser pulses Some applications of polymer films require the microstructuring of partly uneven substrates. This cannot be achieved by conventional photolithography, usually performed with ultraviolet short-pulse lasers (excimer, fourth harmonic Nd:YAG). When processing thermally sensitive or undoped polymers with low optical absorption, the use of femtosecond laser pulses can improve the ablation precision, also reducing the heat-affected zone. Therefore, a Ti:sapphire laser system was employed to perform ablation experiments on polyimide (PI). The irradiated areas were evaluated by means of optical and scanning electron microscopy. Highly oriented ripple structures, which are related to the polarization state of the laser pulses, were observed in the cavities. The relationship between the ablation threshold fluence and the number of laser pulses applied to the same spot is described in accordance with an incubation model. Berlin Springer 1999 Applied physics A 69 5th International Conference on Laser Ablation ; COLA '99 Göttingen, Germany 1999-07-19 1999-07-23 7 S395 S398 10.1007/s003390051424 2016-02-19