Laser-plasma lens for laser-wakefield accelerators

Thanks to their compactness and unique properties, laser-wakefield accelerators are currently considered for several innovative applications. However, many of these applications-and especially those that require beam transport-are hindered by the large divergence of laser-accelerated beams. Here we propose a collimating concept that relies on the strong radial electric field of the laser-wakefield to reduce this divergence. This concept utilizes an additional gas jet, placed after the laser-wakefield accelerator. When the laser pulse propagates through this additional gas jet, it drives a wakefield which can refocus the trailing electron bunch. Particle-in-cell simulations demonstrate that this approach can reduce the divergence by at least a factor of 3 for realistic electron bunches.