Relativistic Four Wave Interactions Enabled Through Nonlinear Resonance Conditions

Four wave interactions at mildly relativistic intensities could be harnessed to generate high energy and high frequency laser pulses [1]. Four wave interactions are additionally complicated by relativistic self- and cross-beam phase modulation. Depending on the context, phase modulation may restrict [2] or widen [3,4] the viable parameter regime for efficient energy conversion. We further analytically and numerically explore how the combination of these two relativistic processes could be manipulated to create unique amplification regimes.

[1] Malkin, V. M., and N. J. Fisch. "Towards megajoule x-ray lasers via relativistic four-photon cascade in plasma." Physical Review E 101.2 (2020): 023211.

[2] Griffith, Alec, Kenan Qu, and Nathaniel J. Fisch. "Modulation-slippage trade-off in resonant four-wave upconversion." Physics of Plasmas 28.5 (2021): 052112.

[3] Malkin, V. M., and N. J. Fisch. "Resonant four-photon scattering of collinear laser pulses in plasma." Physical Review E 102.6 (2020): 063207.

[4] Malkin, V. M., and N. J. Fisch. "Super-resonant four-photon collinear laser frequency multiplication in plasma." Physical Review E 105.4 (2022): 045207.