Diode-pumped Solid State Lasers With Peak Powers from 100 TW up to 1 PW

The POLARIS laser system operated at the Helmholtz-Insitute Jena is currently the only fully diode-pumped laser system in the world reaching peak powers of 200 TW which can be used for experiments at ultrahigh peak intensities. Together with the JETI system, POLARIS serves as an experimental tool for a large number of experiments e.g. on laser-driven particle acceleration at HI-Jena.

To fulfill the requests from experimentalists working with such high-power laser systems, POLARIS also serves as a unique platform to further develop the technology of diode-pumped solid state laser systems. In addition to several new methods aiming at an improvement of the laser pulse contrast the POLARIS power amplifiers are gradually modified to reach even higher pulse energies and peak powers at higher repetition rates in the near future. Here, new amplifier architectures e.g. based on relay-imaging are implemented. For the last amplifier A5 several specifically adapted computer-based control and alignment algorithms had to be developed, tested and implemented into the system. This lead to e.g. a significant homogenization of the intensity distribution of the pump light which strongly improved the achievable gain in this amplifier.

In addition, cryogenic cooling methods are developed and tested for the different amplifiers in a number of separate setups to allow in parallel for a daily laser operation of the POLARIS system. These tasks will eventually lead to an improved efficiency of the whole laser and to a higher repetition rate of the amplified pulses.

All these new technologies which are developed for and tested with the POLARIS system can then be transfered to similar systems as they are currently set up within the Helmholtz association (e.g. at HZDR in Dresden) and for potential future Helmholtz-beamlines for FAIR at GSI in Darmstadt and for the European XFEL at DESY in Hamburg.