High-repetition-rate, all-reflective optical guiding and electron acceleration in helium using an off-axis axicon

Abstract We present recent results on high-power guiding and laser wakefield acceleration in the ELectron Beam Accelerator (ELBA) beamline at ELI Beamlines, using the L3-HAPLS laser system (13 J, 30 fs, 0.2 Hz). By employing self-waveguiding in a 20 cm plasma channel in helium, we achieved stable acceleration of electron beams to energies of approximately 5 GeV. A novel all-reflective optical setup, including an off-axis reflective axicon, enabled efficient acceleration at 0.2 Hz and guiding at repetition rates up to 3.3 Hz. This compact single laser, single-compressor implementation of plasma channels for electron acceleration stabilizes electron pointing and enhances energy gain without requiring modifications to the laser system, paving the way for broader adoption of the technology across user facilities.