FBH shows first diode laser bars with 2kW output
A team at the Ferdinand-Braun-Institut, Leibniz-Institut fuer Höchstfrequenztechnik (FBH) led by Paul Crump, has presented the latest results from its project CryoLaser, demonstrating for the first time a single 1cm laser bar can deliver at least 2kW of optical output when cooled to 203K.
The laser diode bars delivered 2kW peak power per bar at a current of 2kA, a pulse width of 200µs and 10Hz repetition rate, corresponding to a pulse energy of 0.4J.
Conversion efficiency was 65 percent at 1kW output and 56 percent at 2kW. FBH believes this is a worldwide best result for 940nm laser diodes at temperatures of -70degC (203K). To date, such powers could only be achieved by combining the optical beams from at least four single bars.
A number of teams of scientists are working on new generations of ultra-high energy lasers as tools for basic science, for novel medical applications and, not least, for laser-induced fusion. But ultra-high power laser systems require diode lasers that are not just extremely capable, but also manufacturable at low cost in very high volumes.
Diode lasers bars in the wavelength range 930 to 970nm are fundamental building blocks for pump sources for Ytterbium-doped crystals in large laser facilities, where optical pulses are generated with peta-watt class peak energies and picosecond pulse widths.
FBH is optimising both the necessary design and technology of diode lasers as part of the Leibniz project CryoLaser, which targets high energy laser applications of the future. The results were discussed at a talk and a tutorial at CLEO 2015 in San Jose, USA.
Currently, the FBH team is working to further increase the electro-optical conversion efficiency of these bars.
The FBH is responsible for the full value chain within this development project, from design to construction of first prototypes. The final pump sources are being evaluated for potential use in high-energy-class diode-pumped solid-state laser systems together with the world-leading groups in the field.
