High-energy diode-pumped D2O-cooled multislab Yb:YAG and Yb:QX-glass lasers.

We investigated the lasing performance of a multislab Yb:QX and Yb:YAG laser amplifiers using a facet-cooled design. Di-deuterium oxide (D2O) was used as the coolant flowing between the active slabs with the pump and laser light passing through the very low absorbing heavy-water films. A square pump profile at a maximum intensity of 40  kW/cm2 drove the amplifier with a peak fluence of 5.

High average power spectral beam combining of four fiber amplifiers to 8.2 kW.

We report on the incoherent beam combination of the four narrow-linewidth fiber amplifier chains running at different wavelengths. Each main amplifier stage consists of a large-mode-area photonic crystal fiber delivering more than 2 kW of optical power. The four output beams are spectrally combined to a single beam with an output power of 8.