Overview and details of the sessions of this conference. Please select a date or location to show only sessions at that day or location. Please select a single session for detailed view (with abstracts and downloads if available).
Please note that all times are shown in the time zone of the conference. The current conference time is: 4th Aug 2021, 02:02:57am CEST
Session Chair: Prof. Emmanuel I. Stratakis, Institute of Electronic Structure and Lasers, Greece
Location:Room 1 ICM
3:30pm - 3:45pm
High speed temperature measurement in ultrashort pulse laser micromachining
Jiri Martan, Lucie Prokešová, Denys Moskal, Bernardo Campos Ferreira de Faria, Milan Honner, Vladislav Lang
University of West Bohemia, Czech Republic
Ultrashort pulse laser micromachining is affected by the heat accumulation resulting from the previous laser pulses. Up to now, most of the works analysed the accumulation by numerical modelling. The present work focussed on development of a temperature measurement system and its application directly during the process in nanosecond and microsecond time ranges. The measurement system was based on the infrared radiometry and a specific calibration was done in order to obtain temperatures from the measured signal. Micromachining of grooves was done using a picosecond laser with different pulse energies, repetition frequencies and scanning speeds. Obtained heat accumulation temperature ranged from 300°C to 2600°C. Surface roughness and ablation rate were determined by 3D confocal microscope. Good correlation was found between the roughness and the heat accumulation temperature, thus confirming the validity of calibration. Measured heat accumulation temperature was surprisingly the highest for the most efficient ablation parameters producing low roughness.
3:45pm - 4:00pm
Ultrafast laser micromachining of x-ray gratings and sub-micron hole patterns with differ ents beam shapes
Romain Carreto1, Beat Lüscher1, Ronald Holtz1, Bojan Resan1,2
1Institute of Product and Production Engineering (IPPE), University of Applied Sciences and Arts Northwestern Switzerland (FHNW), Switzerland; 2Faculty of Medicine, Josip Juraj Strossmayer University, Croatia
4:00pm - 4:15pm
Laser shock micro-forming of stainless steel: thermal effects at high repetition ps-pulses
David Munoz-Martin1,2, José Manuel López1,3, Miguel Morales1,3, Laura Rivera1,4, Juan José Moreno-Labella1,3, Arturo Chávez-Chávez4, Gilberto Gomez-Rosas4, Carlos Molpeceres1,3
1Centro Láser, Universidad Politécnica de Madrid, Spain; 2Escuela Técnica Superior de Ingeniería y Diseño Industrial, Universidad Politécnica de Madrid, Spain; 3Escuela Técnica Superior de Ingeniería Industrial, Universidad Politécnica de Madrid, Spain; 4Departamento de Física, Centro Universitario de Ciencias Exactas e Ingeniería, Universidad de Guadalajara, Guadalajara, Jalisco, Mexico.
A solid-state ps-pulsed laser, emitting at 1064 nm and repetition rate from 0.4 to 10 kHz, was used to laser peen form thin stainless steel metal sheets (50 μm thick). The laser repetition rate and the scanning speed were adjusted to keep the pitch distance between consecutive laser pulses constant.
The effect of the treatment was measured by the bending angle induced. When using the lowest repetition rate, up to 90º bending angles are achieved. As the laser repetition rate increases, the bending angle is dramatically reduced although every sample was processed with the same total number of pulses and with the same pulse energy.
Despite the small temperature increase in the whole sample, the local accumulative thermal effect at high pulse repetition has a strong influence on the bending angle. High temperature relaxes the stress induced by laser peen treatment and thus prevents bending the sample.
4:15pm - 4:30pm
Femtosecond laser micromachining and rocket propulsion of microparticles optically trapped in hollow-core photonic crystal fibre
Mariia Romodina, Shangran Xie, Abhinav Sharma, Francesco Tani, Philip Russel
Max Planck Institute for the Science of Light, Germany
4:30pm - 4:45pm
Cut edge quality in laser ablation of micrometer-scale grating structures
Meike Zilm, Tim Radel
Bremer Institut für angewandte Strahltechnik GmbH, Germany
During the production of grid structures heat accumulation occurs due to the limited surface area for heat dissipation via the ridge structures. This impairs the edge quality, affecting the ridge width and rectangularity. Due to thermal stresses and expansions, in combination with the low stiffness of the ridges, distortion or failure of these can occur. The aim of this study is to quantify the influence of the strategy for cutting out a single cutout with regard to the cut edge quality. For this purpose, 100 µm thick aluminium foils are processed by means of picosecond laser with different scanning strategies and subsequently examined for their ridge width. It is shown that a laser starting point at half the length of the ridges reduces the ridge width deviation. Furthermore, the ridge width deviation can be reduced by an adapted scanning strategy of the entire grid.