Multipetawatt laser technology opens the door to research in areas such as plasma and high-energy-density physics, astrophysics, laser-driven particle acceleration, enhanced medical diagnostics, industrial processing techniques, and nuclear materials detection. The HELD gratings from LLNL deliver 3.4× more total energy than current state-of-the-art technology. They were developed via a collaboration among LLNL’s Diffractive Optics Group, ELI-Beamlines, Spectra Physics-Newport, and National Energetics. Petawatt and multipetawatt lasers rely on chirped pulse amplification to stretch, amplify, and then compress a high-energy laser pulse to avoid damaging optical components. Pulse-compression gratings must be sufficiently large, efficient, and robust to withstand the high fluence (energy density) of the laser pulses generated by petawatt-class lasers such as the National Ignition Facility’s (NIF) Advanced Radiographic Capability (ARC). According to LLNL senior laser scientist Hoang Nguyen, the HELD gratings are advancements over the NIF ARC-like gratings and allow for significantly higher energy outputs. The 85- × 70-cm HELD gratings are configured at a Littrow angle (the angle of maximum grating efficiency) of 37º and allow for a larger beamwidth — 62.5 cm. “Increasing the beam height to produce a square beam and accounting for the difference in LIDT (laser-induced damage threshold) results in approximately 3.4× more total energy on the grating compared to the ARC high-dispersion, 76.5º-angle-of-incidence grating design,” Nguyen said.