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[Laser Institute of America ICALEO?? 2014: 33rd International Congress on Laser Materials Processing, Laser Microprocessing and Nanomanufacturing - San Diego, California, USA (October 19a??23, 2014)] International Congress on Applications of Lasers & Electro-Optics - Laser ablation cutting of thin silicon subtrates with tunable ultra-short pulsed lasers from 200FS-10PS
摘要： In this paper the influence of the pulse duration in a range of 200 fs up to 10 ps on the cutting process of thin silicon is investigated. The experiments are carried out with a Light Conversion Pharos with various pulse duration between 190 fs and 10 ps. The laser is operated at the second harmonic wavelength of 515 nm and a repetition rate of 200 kHz. Although the ablation threshold, which is determined with the method of Liu [1], amounts 0.27 J/cm2 for 0.2, 1 and 10 ps, one can find extremely different ablation behavior during the cutting experiments. It turns out that independent from pulse energy and pulse overlap the shortest pulse duration at 200 fs leads to a deeper cutting depth and furthermore to a higher cutting speed. This difference can be explained with higher pulse peak intensities and shorter interaction time between laser and material for the 200 fs pulse duration. Nevertheless the general ablation geometry is very similar for all tested pulse durations. We explain this with a simple geometric model. This model considers the projection from a Gaussian beam profile in an existing cutting kerf.
关键词： cutting process,laser ablation,ultra-short pulsed lasers,pulse duration,thin silicon substrates
更新于2025-09-23 15:19:57
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[Laser Institute of America ICALEO?? 2016: 35th International Congress on Applications of Lasers & Electro-Optics - San Diego, California, USA (October 16a??20, 2016)] International Congress on Applications of Lasers & Electro-Optics - Optimized strategies for seamless stitching with synchronized galvo scanner and linear axis
摘要： Laser surface texturing using ultra short pulsed lasers in combination with galvo scanners is limited to the scan field of the galvo scanner which is typically 65x65 mm using a 160 mm objective. By combine the galvo scanner with an additional high precision linear axis, it is possible to enhance the working field. Increased surface roughness and visible seams in the intersection region have to be avoided to preserve the high quality achieved by using ultra short pulsed laser systems. Strategies to minimize this influence are developed by using a system with a synchronized galvo scanner and by working with b/w bitmaps in a raster scanning mode. This allows splitting an image into two sub-images and compare different strategies for its recombination on the sample. For these tests always the whole image is scanned but with laser switched off alternating for the left and the right sub-image. This setup offers the possibility to evaluate different stitching strategies for the combination of two sub-images without influence of the exact alignment of the linear axis to the galvo scanner. Transferring the stitching strategy to a system including one or two linear axes needs a perfect alignment of the two coordinate systems to preserve the high accuracy. Therefore, a solution for aligning the two coordinate systems with highest accuracy will be presented as well.
关键词： galvo scanners,laser surface texturing,ultra short pulsed lasers,stitching strategies,linear axis
更新于2025-09-16 10:30:52