Laser wakefield acceleration with high-power, few-cycle mid-IR lasers

The study of laser wakefield electron acceleration (LWFA) using mid-IR laser drivers is a promising path for future laser driven electron accelerators, when compared to traditional near-IR laser drivers operating at 0.8-1 mu m central wavelength (lambda(laser)), as the necessary vector potential (a(0)) for electron injection can be achieved with smaller laser powers due to the linear dependence on lambda(laser). In this work, we perform 2D PIC simulations on LWFA using few-cycle, high power (5-15 TW) laser systems with lambda(laser) ranging from 0.88 to 10 mu m. Such fewcycle systems are currently under development, aiming at Gas High Harmonics Generation applications, where the favorable lambda(2)(laser) scaling extends the range of the XUV photon energies. We keep a(0) and n(e)/n(cr) (n(e) being the plasma density and n(cr) the critical density for each lambda(laser)) as common denominators in our simulations, allowing for comparisons between drivers with different lambda(laser), with respect to the accelerated electron beam energy, charge and conversion efficiency. While the electron energies are mainly dominated by the plasma dynamics, the laser to electron beam energy conversion efficiency shows significant enhancement with longer wavelength laser drivers. (c) 2018 Elsevier B.V. All rights reserved.