The laser is nearing completion with demonstration of 73% frequency-conversion efficiency, deformable mirror operation that generated a 4-times diffraction limited spot, and commissioning of an advanced front end to be installed on the main laser.

We report on the operation of the Mercury laser with fourteen 4 × 6 cm 2 Yb:S-FAP amplifier slabs pumped by eight 100 kW peak power diode arrays. The system was continuously run at 55 J and 10 Hz for several hours, (2 × 10 5 cumulative shots) with over 80% of the energy in a 6 times diffraction limited spot at 1.047 μm. Improved optical quality was achieved in Yb:S-FAP amplifiers with magneto-rheological finishing, a deterministic polishing method. In addition, average power frequency conversion employing YCOB was demonstrated at 50% conversion efficiency or 22.6 J at 10 Hz.

The Mercury laser operated continuously for several hours at 55J and 10Hz with fourteen 4×6 cm2 Yb:S-FAP amplifier slabs pumped by eight 100kW diode arrays. Average power frequency conversion employing YCOB yielded 50% conversion efficiency.