SCHWEISSEN & SCHNEIDEN 2017

•••4••• Innovationen Messe-Rundgang zur Anzeigen-Spezial SCHWEISSEN& SCHNEIDEN2017 Workshop zu Laserbearbeitung Das Schweißen thermoplasti- scher Faserverbundstrukturen, die Darstellung der Online-Pro- zessbeobachtung sowie Umriss- bearbeitung, Bohren, laserbasier- te Reparaturvorbereitung und Oberflächenvorbehandlung sind am 28. August 2018 Themen ei- nes Workshops zur Laserbearbei- tung von Faserverbundwerkstof- fen. Die Veranstaltung findet im Laser Zentrum Hannover statt. Cool by diamond Scientists develop new generation of semiconductor lasers How can semiconductor disk la- sers further be improved in terms of output power without losing their other wonderful properties? Scientists from the “Institut für Halbleiteroptik und Funktionelle Grenzflächen” examined this is- sue. The key solution sounds sim- ple and is consequent though chal- lenging as it is in most cases when going into practice. Semiconductors themselves are poor thermal conductors. So one has just to omit all parts of the semiconductor structure not es- sentially necessary to build up a whole laser: the substrate on which the semiconductor layers are deposited has no function during laser operation and can be removed. External mirrors can re- place the semiconductor mirror, integrated in all semiconductor disk lasers. The only thing left of the semicon- ductor component is the several few hundreds of nanometres thick laser active region which gets sand- wiched between two diamond disks. Diamond – transparent and the best thermal conductor avail- able – is suitable in an outstanding way as an integrated heat spread- er. The PhD-Students Hermann Kahle and Cherry May Mateo started with wet-chemical etching processes to isolate the laser ac- tive region from its substrate. The semiconductor membrane, in total thickness only one eightieth of the diameter of a regular human hair, can be stored and best handled when submerged in a liquid only. The exciting thing at the end was to transfer the membrane onto a diamond disk which is four mil- limetre in diameter and 0.5 milli- metre in thickness. Likewise, it has to keep in one piece, centered to the diamond and totally flat. And, there was never a second chance. Once bonded to the diamond by capillary forces it was impossible to remove the membrane again without destroying it. Laboratory work like this requires calm hands, lots of skill and endurance. The completed diamond-semiconduc- tor-sandwich was then inserted into a laser resonator and charac- terized in the optics laboratory. After hours of adjustment work it flashed and the membrane la- ser was operating. A strong light beam in the red spectral range was emitted after a little more fine adjustment. And, it showed all characteristics the scientists had hoped for: the tunability of the laser wavelength during op- eration, a perfectly shaped beam profile and especially a for semi- conductor lasers high output power; and all this at an operating temperature of 10 °C. Without the diamond sandwich the semicon- ductor membrane would rapidly overheat and stop to operate. Be- fore this approach the whole sem- iconductor disk laser device some- times had to be cooled down to minus 30 °C. Diamond-semiconductor-sandwich Photo: Hermann Kahle Ihr monatlicher Newsletter: Messe-News Metals / Tools Die neuesten Nachrichten über Messen wie: ALUMINIUM | AMB | BLECHEXPO / Schweisstec | EMO | EuroBLECH | EUROGUSS | Euromold | formnext | HANNOVER MESSE | METAV | SCHWEISSEN & SCHNEIDEN | SurfaceTechnology GERMANY und weitere http://www.exxpo.com/newsletter/158/779 Continued from page 1 Non contact MT-testing and demagnetization with DC pulse. www.hirsch-prueftechnik.de HPT Hirsch Prüftechnik GmbH D-66482 Zweibrücken SCHWEISSEN & SCHNEIDEN • Halle 14 , Stand D03 Der UCI-Härteprüfer Schweiß-Naht mit HV10 (UCI). Sofort einsatzbereit, schnell, selektiv, in jeder Richtung. Halle 15, Stand 15B07 NewSonic GmbH Tel.: 07121-6808550 info@newsonic.de www.newsonic.de SonoDur2