“CryoLaser”: Innovative cryogenic diode laser bars optimized for emerging ultra-high power laser applications

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 lasers 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 realistic laser-induced fusion systems. The objectives are to increase the emitted optical output power density by a factor of ~10 and to increase the power conversion efficiency at the operation point to > 80% (reducing the dissipated heat by a factor of 3). Also, internal gratings must be introduced into the diode lasers, for reduced spectral width. These improvements are to be achieved by developing innovative new device designs for use at sub-zero (-73°C, 200K) temperatures. This includes the development of new and improved simulation tools, fabrication and mounting of diode laser bars and stacks with innovative designs to the highest quality level as well as the installation of test facilities at 200K for verification of the results.

Research, technology development and prototype construction of diode lasers will be performed at the FBH. However, in order to ensure that the technology developed will be suitable for later transfer into real systems, the work will be done in cooperation with the world leading groups involved in developing laser-induced fusion (LIFE in the USA, HiPER in the EU), who will assess prototypes delivered by the FBH.