Power-in-bucket enhancement in tiled-aperture coherent beam combining through inducing spatial chirp

Spatial gaps between sub-beams in high-peak-power lasers with tiled-aperture-based coherent beam combining (TACBC) give rise to relatively strong sidelobes and impair the power in bucket (PIB) at far field. To address the aforementioned issue, spatial chirp is employed in this paper to fill the gaps and further enhance PIB. With two sub-beams, both simulations and experiments indicate that spatial chirp can boost PIB by 1.8 times at a gap-beam width ratio of 0.2. The same enhancement is observed in simulations even when four sub-beams are considered. To put it briefly, the spatial-chirp-assisted TACBC approach holds the potential in boosting focal intensity during constructing tens to hundreds of petawatt (PW) lasers.