Generation and Coupling of Short-Pulse High-Intensity Spatio-Temporal Light Springs to Underdense Plasma

Laser-plasma interactions driven by intense beams carrying orbital angular momentum (OAM) have become accessible with recent advances in optics manufacturing. However, transferring OAM plasma waves can be challenging as OAM is typically encrypted only in the laser phase and plays little to no role in ponderomotively driven interactions such as wakefield acceleration. Spatio-temporal structures carrying OAM can be created from the superposition of 2 or more OAM beams with different wavelengths. Referred to as ‘light springs’, these beams propagate with an intensity profile that is azimuthally dependent allowing for ponderomotive coupling of OAM to plasmas. In this work, we analyze the interaction of short-pulse, high-intensity light springs with underdense plasma, and propose methods for generating and measuring light springs at high intensities. Using simulations in both 3D and 2.5D PIC codes, we show strong coupling of the light spring OAM to plasma. We will discuss the novel interaction physics of these beams leading to self-magnetizing wakefields and associated effects.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344. This work was funded by the Laboratory Directed Research and Development Program at LLNL under project tracking code 24-ERD-031. This work was also supported by the NSF under award PHY-1753165 and DMR-1548924, and by the DOE under award DE-SC0023504.