Coherently tiled Ti:sapphire laser amplification: a way to break the 10 petawatt limit on current ultraintense lasers

After reaching a world record of 10 PW, the peak power development of the titanium-sapphire (Ti:sapphire) PW ultraintense lasers has hit a bottleneck, and it seems to be difficult to continue increasing due to the difficulty of manufacturing larger Ti:sapphire crystals and the limitation of parasitic lasing that can consume stored pump energy. Unlike coherent beam combining, coherent Ti:sapphire tiling is a viable solution for expanding Ti:sapphire crystal sizes, truncating transverse amplified spontaneous emission, suppressing parasitic lasing, and, importantly, not requiring complex space-time tiling control. A theoretical analysis of the above features and an experimental demonstration of high-quality laser amplification are reported. The results show that the addition of a 2×2 tiled Ti:sapphire amplifier to today’s 10 PW ultraintense laser is a viable technique to break the 10 PW limit and directly increase the highest peak power recorded by a factor of 4, further approaching the exawatt class.