Low emittance electron beam generation from a laser wakefield accelerator using two laser pulses with different wavelengths

Abstract

Ionization injection triggered by short wavelength laser pulses inside a nonlinear wakefield driven by a longer wavelength laser is examined via multi-dimensional particle-in-cell simulations. We find that very bright electron beams can be generated through this two-color scheme in either collinear propagating or transverse colliding geometry. For a fixed laser intensity $I$, lasers with longer/shorter wavelength $\lambda$ have larger/smaller ponderomotive potential ($\propto I{\lambda }^2$). The two color scheme utilizes this property to separate the injection process from the wakefield excitation process. Very strong wakes can be generated at relatively low laser intensities by using a longer wavelength laser driver (e.g. a $10 \micro\meter$ CO${}_2$ laser) due to its very large ponderomotive potential. On the other hand, short wavelength laser can produce electrons with very small residual momenta ($p_{\perp }\sim a_0\sim \sqrt{I}\lambda$) inside the wake, leading to electron beams with very small normalized emittances (tens of $\nano\meter$). Using particle-in-cell simulations we show that a $\sim10 \femto\second$ electron beam with $\sim4 \pico\coulomb$ of charge and a normalized emittance of $\sim 50 \nano\meter$ can be generated by combining a 10 $\micro\meter $ driving laser with a 400 $\nano\meter$ injection laser, which is an improvement of more than one order of magnitude compared to the typical results obtained when a single wavelength laser used for both the wake formation and ionization injection.

18 pages (one column), 7 figures

References in corpus (3)

• Generating multi-GeV electron bunches using single stage laser wakefield acceleration in a 3D nonlinear regime
• Enhancement of electron energy to multi-GeV regime by a dual-stage laser-wakefield accelerator pumped by petawatt laser pulses
• Phase Space Dynamics of Ionization Injection in Plasma Based Accelerators

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• A near-ideal dechirper for plasma-based electron and positron acceleration using a hollow channel plasma
• Ultra-Bright Electron Bunch Injection in a Plasma Wakefield Driven by a Superluminal Flying Focus Electron Beam
• High quality electron beam acceleration by ionization injection in laser wakefields with mid-infrared dual-color lasers
• Effects of Laser Polarization and Color on Hybrid Laser Wakefield and Direct Acceleration
• On the generation of ultra-bright and low energy spread electron beams in laser wakefield acceleration in a uniform plasma
• Generation of Low Absolute Energy Spread Electron Beams in Laser Wakefield Acceleration Using Tightly Focused Laser through Near-Ionization-Threshold Injection
• Accurate simulation of direct laser acceleration in a laser wakefield accelerator
• Colliding ionization injection in a beam driven plasma accelerator
• Electron self-injection threshold for the tandem-pulse laser wakefield accelerator
• Generation of topologically complex three-dimensional electron beams in a plasma photocathode