Fraunhofer ILT opens up new ways of ultraprecise laser materials processings

Researchers at the Fraunhofer Institute for Laser Technology ILT have developed an amplification concept for femtosecond lasers (fs laser). As a result, they have been able to achieve mean power in the kilowatt range for the first time. While lasers with continuous radiation (cw) are often used to cut and weld, pulsed lasers are mostly used to ablate. For the latter, following generally applies – the shorter the pulse, the smaller the heat penetration depth, the higher the temperature at the material surface, and the higher the precision of the material processing. The shorter pulses of the fs laser enable greater precision when ablating via vaporization. In addition, materials can be processed that can only be poorly processed with lasers, or not at all.

Dr. Peter Rußbüldt, project leader at the Fraunhofer ILT, has cascaded two INNOSLAB amplifiers. In this way, the amplifier chain was able to generate a mean power of 1.1 kW at a peak pulse power of 80 MW and a pulse duration of 600 femtoseconds. The Aachen researchers have thus reached a new record. “Thanks to this new power output, the fs laser slowly departs from its image as a scientifically complicated toy,” says Dr. Rußbüldt. “The higher power means the throughput also increases in production, which, in turn, means an enormous time and cost-based advantage for manufacturers. Therefore, the fs laser can now be applied in fields in which its throughput did not suffice in the past.” Typical applications of the fs laser in the macro sector are manufacturing processes for fiber-composite lightweight components. An fs laser can process the most varying of materials irrespective of their characteristics. In the micro sector the applications of this new beam source range from drilling of nozzles to tool engineering, solar cell engineering all the way to printing technology.

At the SPIE Photonics West (San Francisco, USA, January 25 -27, 2011), the Fraunhofer ILT will be showing high-precision assembly technology for optical components in the German Pavilion North Hall at Stand 4601 and presenting further developments of heat sinks for high-power diode lasers. In the accompanying conference (LASE, January 22 - 27, 2011), the Aachen experts will be presenting the new high-power lasers to the specialist audience.

Contact: Axel Bauer, Fraunhofer Institute for Laser Technology ILT
axel.bauer@ilt.fraunhofer.de