TY - JOUR A1 - Krüger, Jörg A1 - Kautek, Wolfgang A1 - Lenzner, M. A1 - Krausz, F. T1 - Photoablation with sub-10 fs laser pulses N2 - Ablation experiments in several glasses with single and multishot irradiation by laser pulses in the 10-fs pulse duration domain are presented; physical and technological implications are discussed. We demonstrate that these short pulses offer the potential for lateral and vertical machining precision of the order of 100 nm. KW - Ablation KW - Laser pulses KW - Femtosecond pulses PY - 2000 DO - https://doi.org/10.1016/S0169-4332(99)00432-8 SN - 0169-4332 SN - 1873-5584 VL - 154-155 SP - 11 EP - 16 PB - North-Holland CY - Amsterdam AN - OPUS4-800 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rudolph, Pascale A1 - Bonse, Jörn A1 - Krüger, Jörg A1 - Kautek, Wolfgang T1 - Femtosecond- and nanosecond-pulse laser ablation of bariumalumoborosilicate glass N2 - Laser ablation with femtosecond pulses (130 fs, wavelength 800 nm, repetition rate 2 Hz) was compared with nanosecond-pulse ablation (10 ns, wavelength 266 nm, repetition rate 2.5 Hz) of bariumalumoborosilicate glass in air using the direct focusing technique. Different ablation thresholds and heat-affected zones were observed. The lateral and vertical machining precision was evaluated. Single nanosecond laser pulses in the far UV resulted in a bubble or a circular hole in the centre of the illuminated spot, depending on the applied fluence. The ablation behaviour in the case of near-IR femtosecond pulses contrasted to this. Bubble formation was not detected. It needed repeated pulses at the same spot to modify the surface until material removal could be observed (incubation). Cavity dimensions of less than the beam diameter were achieved in this case. T2 - 5th International Conference on Laser Ablation ; COLA '99 CY - Göttingen, Germany DA - 1998-07-19 KW - Laser ablation KW - Bariumalumoborosilicate glass PY - 1999 DO - https://doi.org/10.1007/s003390051524 SN - 0947-8396 VL - 69 IS - 7 SP - S763 EP - S766 PB - Springer CY - Berlin AN - OPUS4-801 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Krüger, Jörg A1 - Lenzner, Matthias A1 - Martin, Sven A1 - Lenner, M. A1 - Spielmann, C. A1 - Fiedler, A. A1 - Kautek, Wolfgang ED - Phipps, C. R. T1 - Femtosecond laser induced damage in absorbing filters used for laser protection N2 - Damage experiments of absorbing filters (Schott BG18 and BG36) were performed with Ti:sapphire laser pulses with durations from 30 fs to 340 fs (800 nm, 1 kHz) in air. The direct focusing technique was employed under single- and multi-pulse irradiation conditions. Ablation threshold fluences were determined from a semi-logarithmic plot of the ablation crater diameter vs. laser fluence. The damage threshold fluence decreases for shorter pulse durations. In the investigated pulse duration range, the measured multi-pulse ablation threshold fluences are practically similar to those of undoped glass material (~1 Jcm-2). That means that the multi-pulse ablation threshold is independent on the doping level of the filters. For more than 100 pulses per spot and all pulse durations applied, the threshold fluence saturates. This leads to technically relevant damage threshold values in the femtosecond laser pulse duration domain. T2 - 4th SPIE's International Conference on High-Power Laser Ablation CY - Taos, NM, USA DA - 2002-04-22 KW - Ablation KW - Damage KW - Eye protection KW - Femtosecond pulse laser KW - Incubation KW - Laser safety KW - Threshold fluence PY - 2002 SN - 0-8194-4524-X DO - https://doi.org/10.1117/12.482109 SN - 1605-7422 N1 - Serientitel: SPIE proceedings series – Series title: SPIE proceedings series VL - 1 IS - 4760 SP - 398 EP - 405 PB - SPIE CY - Bellingham, Wash. AN - OPUS4-1550 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kautek, Wolfgang A1 - Daminelli-Widany, Grazia A1 - Meja, P. A1 - Cortona, Anna A1 - Krüger, Jörg A1 - Autric, M. ED - Phipps, C. R. T1 - Femtosecond and nanosecond laser removal of anodic oxide layers from aluminium T2 - 4th SPIE's International Conference on High-Power Laser Ablation CY - Taos, NM, USA DA - 2002-04-22 KW - Laser ablation KW - Laser spallation KW - Microphone KW - Acoustical measurement KW - Aluminium oxide PY - 2002 SN - 0-8194-4524-X SN - 1605-7422 N1 - Serientitel: SPIE proceedings series – Series title: SPIE proceedings series IS - 4760 SP - 239 EP - 246 PB - SPIE CY - Bellingham, Wash. AN - OPUS4-1551 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Jörg A1 - Bonse, Jörn A1 - Lenzner, Matthias T1 - Modification and Ablation of Semiconductors by Femtosecond Laser Pulses N2 - Physical and chemical phenomena resulting from irradiation of silicon and indium phosphide with ultrashort laser pulses (~100fs) were investigated with respect to the difference between single- and multiple-pulse treatment. In the single-pulse case, several processes were identified: modification, recrystallization and ablation. All processes exhibit a distinct treshold behaviour. A two photon-absorption coefficient can be determined from a single spatial ablation profile. Accumulation effects were observed for multi-pulse illumination. Different morphological features like bubbles, rippels and microcolumns were found. PY - 2002 VL - 5 IS - 2 SP - 437 EP - 461 PB - Transworld Research Network CY - Trivandrum AN - OPUS4-1585 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kautek, Wolfgang A1 - Daminelli-Widany, Grazia A1 - Krüger, Jörg T1 - Femtosecond and Nanosecond Pulse Laser Electrochemistry of Aluminium Alloys T2 - 53th Annual meeting of the International Society of Electrochemistry CY - Düsseldorf, Germany DA - 2002-09-15 PY - 2002 SP - 1(?) PB - DECHEMA CY - Frankfurt a.M. AN - OPUS4-1586 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kautek, Wolfgang A1 - Krüger, Jörg A1 - Lenzner, Matthias A1 - Martin, Sven A1 - Lenner, M. A1 - Spielmann, C. A1 - Fiedler, A. ED - Meunier, M. T1 - Single- and multi-pulse femtosecond laser ablation of optical filter materials N2 - Commercially available absorption filters (Schott BG18 and BG36) were investigated with respect to their single- and multi-pulse ablation threshold using laser pulses from a Ti:Sapphire laser in the range between 30 and 340 fs. It could be observed, that the threshold fluence decreases for shorter pulse durations. The similarity of the measured multi-pulse threshold fluences with those of undoped glass material (around 1 J/cm^2 for a pulse duration of 30 fs) suggests that, for very short pulses, the threshold is independent on the doping level and therefore, linear absorption does not significantly contribute to laser-induced damage. For >100 pulses per spot and all pulse durations applied, the threshold fluences saturate. This independence on the number of applied pulses leads to technically relevant damage threshold values. T2 - Symposium D - European Materials Research Society CY - Strasbourg, France DA - 2002-06-18 PY - 2002 UR - http://www.emrs-strasbourg.com/files/pdf/2002_SPRING/02_Prog_Dv2.pdf N1 - Serientitel: Applied surface science – Series title: Applied surface science VL - 208/209.2003,1 IS - 1 SP - 1(?) PB - Elsevier CY - Amsterdam AN - OPUS4-1588 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Baudach, Steffen A1 - Kautek, Wolfgang A1 - Krüger, Jörg A1 - Welsch, E. T1 - Femtosecond laser damage of a high reflecting mirror N2 - Multiple pulse investigations of 130-fs Ti:sapphire laser-induced damage of a high reflecting mirror consisting of alternating ?/4-layers of Ta2O5 and SiO2 and a single 500-nm Ta2O5 film were performed. In both cases, fused silica served as the substrate. For a fixed number of 1000 laser pulses per spot, a decrease in the damage threshold fluence of the mirror by a factor of two was observed by changing the repetition rate from 10 Hz to 1 kHz. A single 500-nm Ta2O5 film shows higher damage resistance compared to the mirror. The mirror and the Ta2O5 film samples were partially coated with a 300-nm-thick aluminium layer. The aluminium coating does not influence the damage threshold of the dielectrics underneath. KW - Aluminium KW - Laser ablation KW - Optical coatings KW - Silicon oxide PY - 2002 DO - https://doi.org/10.1016/S0040-6090(02)00074-3 SN - 0040-6090 IS - 408 SP - 297 EP - 301 PB - Elsevier CY - Amsterdam AN - OPUS4-1382 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, Jörg A1 - Niino, Hiroyuki A1 - Yabe, A. T1 - Investigation of excimer laser ablation threshold of polymers using a microphone N2 - KrF excimer laser ablation of polyethylene terephthalate (PET), polyimide (PI) and polycarbonate (PC) in air was studied by an in situ monitoring technique using a microphone. The microphone signal generated by a short acoustic pulse represented the etch rate of laser ablation depending on the laser fluence, i.e., the ablation “strength”. From a linear relationship between the microphone output voltage and the laser fluence, the single-pulse ablation thresholds were found to be 30 mJ cm-2 for PET, 37 mJ cm-2 for PI and 51 mJ cm-2 for PC (20-pulses threshold). The ablation thresholds of PET and PI were not influenced by the number of pulses per spot, while PC showed an incubation phenomenon. A microphone technique provides a simple method to determine the excimer laser ablation threshold of polymer films. KW - Laser ablation KW - Polymer KW - Treshold KW - Microphone KW - Acoustic measurement KW - Incubation PY - 2002 DO - https://doi.org/10.1016/S0169-4332(02)00418-X SN - 0169-4332 SN - 1873-5584 VL - 197-198 SP - 800 EP - 804 PB - North-Holland CY - Amsterdam AN - OPUS4-1920 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg T1 - Femtosecond Laser Micromachining: Potentials, Applications, Safety Aspects T2 - Materials Seminar Series, Paul Scherrer Institut CY - Villigen, Switzerland DA - 2003-05-19 PY - 2003 AN - OPUS4-4360 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -