High-power diode lasers generate their radiation from bar-shaped semiconductors based on GaAs. They are the most efficient sources of artificial light available. Their broad industrial use is still in the early stages and the potential of this type of laser is far from reaching its limits.
The two JENOPTIK companies — JENOPTIK Diode Lab GmbH in Berlin and JENOPTIK Laserdiode GmbH in Jena — work closely together to manufacture these lasers.
Since the beginning of 2005, the quality of the already excellent semiconductor bars made at the JENOPTIK Diode Lab GmbH in Berlin-Adlershof has continuously been improved. The JENOPTIK Laserdiode GmbH uses those bars to produce semiconductor lasers with up to 120 W cw per bar as standard products. This allows for diode laser stacks with up to 3 kW cw for applications such as thin-disk laser pumping.
For further testing of the limits of this type of semiconductor bar material, the main assembling issues – mounting and cooling techniques – had to undergo additional development stages. Based on this, in August of 2005 a new world record of 454 watts was set for a 10 mm diode laser bar operating in continuous mode.
But this success did not mean that potential of these two companies was exhausted. Further improvements to the optical characteristics by the JENOPTIK Diode Lab GmbH and the optimization of mounting techniques at JENOPTIK Laserdiode GmbH lead to an output beyond the 500-watt barrier for a diode laser in continuous mode—509 watts were reached at 540 amps of operating current.
The testing of diode lasers in regards to their performance limits serves as proof of quality for the semiconductor material and assembling techniques. These investigations are included in the VDI project BRILASI which is part of the BRIOLAS project alliance with funding from BMBF. The goal of this project is to double the current commercially available power of 50-100 watts with enhanced reliability by the end of 2007.
SOURCE: JENOPTIK Laserdiode GmbH