Petawatt-Class Ultra-High-Peak-Power Laser Design for the SCARLET Laser Facility

The OSU High Energy Density Physics (HEDP) group focuses on high-intensity ultra-fast laser experiments, especially those pertaining to fast-ignition fusion. A petawatt-scale upgrade designed to significantly increase the intensity of OSU's SCARLET laser. The beam will have 400 TW peak power at 800 nm wavelength with a 5 $\mu m$ focal spot, delivering $10^{22}$ W/cm$^{2}$ with a $<$ 40 fs pulse at a repetition rate of once per minute. To achieve this, SCARLET uses a 3-pass amplifier (Ti:Sapphire crystal) irradiated by two 25 J, ND:glass 527 nm pump lasers as well as Dual Chirped Pulsed Amplification (DCPA) by way of a new stretcher with a compact mirror-striped grating design to stretch the initial pulse from 25 fs to 800 ps. Several air-spaced achromatic doublets were designed in-house to serve as image-relay telescopes to and from the new amplifier; these have been optimized to minimize chromatic and spherical aberration within the 100 nm bandwidth pulse. Also presented are results from gain modeling performed to predict effects like red-shift and gain narrowing in amplification.