Wavelength Scaling of Laser Wakefield Acceleration for the EuPRAXIA Design Point

Siders Siders,Spinka Spinka,Bayramian Bayramian,Sistrunk Sistrunk,Reagan Reagan,Haefner Haefner,Erlandson Erlandson,Galvin Galvin

doi:10.3390/instruments3030044

Siders Siders, Spinka Spinka + Show 6 more

Open Access

https://doi.org/10.3390/instruments3030044

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Journal: Instruments	Publication Date: Aug 21, 2019
Citations: 12	License type: CC BY 4.0

Affiliation: Lawrence Livermore National Laboratory

Abstract

Scaling the particle beam luminosity from laser wakefield accelerators to meet the needs of the physics community requires a significant, thousand-fold increase in the average power of the driving lasers. Multipulse extraction is a promising technique capable of scaling high peak power lasers by that thousand-fold increase in average power. However, several of the best candidate materials for use in multipulse extraction amplifiers lase at wavelengths far from the 0.8–1.0 μm region which currently dominates laser wakefield research. In particular, we have identified Tm:YLF, which lases near 1.9 µm, as the most promising candidate for high average power multipulse extraction amplifiers. Current schemes to scale the laser, plasma, and electron beam parameters to alternative wavelengths are unnecessarily restrictive in that they stress laser performance gains to keep plasma conditions constant. In this paper, we present a new and more general scheme for wavelength scaling a laser wakefield acceleration (LWFA) design point that provides greater flexibility in trading laser, plasma, and electron beam parameters within a particular design point. Finally, a multipulse extraction 1.9 µm Tm:YLF laser design meeting the EuPRAXIA project’s laser goals is discussed.

Highlights

Laser wakefield acceleration (LWFA) was invented by Tajima and Dawson [1] two decades before the critical 2018 Nobel Prize-winning innovation of Chirped Pulse Amplification (CPA) [2]enabled the construction of lasers of sufficient optical field strength to excite a laser wakefield
From the earliest wakefield observations, Titanium-doped sapphire (Ti:S) [3,4,5] as well as Nd:Glass [6,7], and more recently ytterbium-doped materials have been the laser materials of choice due to their large bandwidths and optimal saturation fluences which permit the production of the necessary ~100-TW peak power robustly and without optical damage, and in compact university-scale facilities
We propose an alternative scheme, multipulse extraction (MPE), in which the gain medium is pumped continuously, and the upper state population is extracted over many pulses

Summary

Introduction

Laser wakefield acceleration (LWFA) was invented by Tajima and Dawson [1] two decades before the critical 2018 Nobel Prize-winning innovation of Chirped Pulse Amplification (CPA) [2]. This method has three primary benefits: first, because efficient extraction is not necessary in a single pulse, the extraction fluence (and the B-integral) can be much lower than in an SPE design; second, there isn’t a need to pump the gain medium within a single inverse lifetime, and less expensive, less complex, and more efficient CW pump sources can be used; and MPE enables the use of high-saturation-fluence materials These materials may have important advantages, such as the ability to be directly diode-pumped, a lower quantum defect, or being in a more useful wavelength regime. CO2 , which arguably has considerable scaling potential via its long wavelength, has to date not been demonstrated with sufficiently short pulse durations (and cycles per pulse) nor has a scalable path to high average power at high peak power and efficiency been identified

Wavelength Scaling

EuPRAXIA Design

Findings

Conclusions