Combination of Up to 21 Frequency Shifted Beams with a Plasma Optic*

A plasma-based optic is demonstrated that combines the energy and fluence of up to 21, 1.1 kJ, frequency shifted laser beams into a single beam, producing an output of up to 7.7 +- 1.7 kJ in a 1ns pulse.   The technique uses Cross Beam Energy Transfer (CBET) and builds on previous work to make beams with energy and fluence beyond that otherwise available at NIF [1].  The self-generated plasma diffractive optic used is far more damage resistant, and inherently capable of producing much higher single beam fluence and radiance than solid state optics.  Such beams are needed for applications, including potentially pumping a second stage of plasma amplification and compression at multi-ps time scales.  The results also aid the validation of models of CBET [2] which predict a larger number of non-resonant pump beams will scale up outputs still further.

[1] R. K. Kirkwood et al Nat. Phys. 14 , 80 (2018).

[2] R. K. Kirkwood  et al Phys. of Plas. 25 056701 (2018).