Advancements in high fluence multilayer dielectric gratings for ultrafast lasers

The advent of high energy, high peak power laser systems through chirped pulse amplification (CPA) in broadband solid-state gain media has opened new avenues into High Energy Density, High Field and Material Science research. There are ongoing efforts at numerous institutions in Europe, USA, and China that are striving to achieve output powers up to 200 PW. One main limitation of total laser energy output is the damage threshold and physical size of diffraction gratings. For the 10 PW (1.5 kJ, 150 fs) ELI-Beamline L4 Aton laser, we have developed a new class of meter-sized, multilayer dielectric (MLD) gratings based a low-dispersion design of 1136 lines/mm for a Littrow out-of-plane compressor design operating at 1060 nm. This new class of MLD gratings allows for approximately 4X more total energy on grating compared to the present state of the art. Fabrication of a 850 mm wide x 700 mm tall grating resulted in 98.7% efficiency with 0.3% uniformity at 1060 nm.