High-power lasers: an energy source of the future?
25 June 2013
This month, the German research organisation, Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik (FBH) was invited to present the latest results of its CryoLaser project to an audience at CLEO 2013, an annual lasers and electro-optics conference held this year in San Jose, USA.
Diode lasers have been the key elements in high power laser systems for decades. Now, a new generation of ultra high power systems based on diode laser technology is under construction world wide, which target laser-induced fusion as a clean, safe, high-efficiency power source, as well as an instrument for basic research.
Although prototypes of smaller systems are possible based on today’s technology, a new kind of diode laser with drastically increased power density, efficiency and reduced spectral width is required for full systems.
The goal of the CryoLaser project is to meet this need by developing the diode laser technology required for the deployment of viable laser-induced fusion systems. The objectives are to increase the emitted optical output power density by a factor of ten and to increase the power conversion efficiency at the operation point to greater than 80 percent (reducing the dissipated heat by a factor of three).
FBH scientist, Paul Crump presented the results of the work, which has hitherto focused on laser bars in the wavelength range 930 to 970nm. Such diode lasers are the fundamental building blocks of 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.
The individual laser bars in these pump sources emit 1.2ms long optical pulses, previously with a typical output power between 300 and 500W. First tests of the FBH developed bars at a temperature of 223K have yielded a world beating result of 1.7kW peak power per bar. To date, such pump energies could only be achieved by combining the optical beams from at least five single bars.
The researchers hope that the technology developed will be suitable for later transfer into real systems, and in order to achieve this goal, the work is currently being conducted in co-operation with leading groups involved in the development of laser-induced fusion, including LIFE in the USA and HiPER in the EU. FBH project partners also include Lawrence Livermore National Laboratory in the USA and STFC Rutherford Appleton Laboratory (Central Laser Facility) in the UK.
For more information about CryoLaser, click here.