Generation of Quantum Vortex Electrons with Intense Laser Pulses

Accelerating a free electron to high-energy forms the basis for studying particle and nuclear physics. Here it is shown that the wave function of such an energetic electron can be further manipulated with the femtosecond intense lasers. During the scattering between a high-energy electron and a circularly polarized laser pulse, a regime is found where the enormous spin angular momenta of laser photons can be efficiently transferred to the electron orbital angular momentum (OAM). The wave function of the scattered electron is twisted from its initial plane-wave state to the quantum vortex state. Nonlinear quantum electrodynamics (QED) theory suggests that the GeV-level electrons acquire average intrinsic OAM beyond <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:mrow><mml:mo>⟨</mml:mo> <mml:mi>l</mml:mi> <mml:mo>⟩</mml:mo> <mml:mo>∼</mml:mo> <mml:mn>100</mml:mn> <mml:mi>ℏ</mml:mi></mml:mrow> <mml:annotation>$\langle l \rangle \sim 100\hbar $</mml:annotation></mml:semantics> </mml:math> at laser intensities of 10²⁰ W cm^-2 with linear scaling. These electrons emit γ-photons with two-peak spectrum, which sets them apart from the ordinary electrons. The findings demonstrate a proficient method for generating relativistic leptons with the vortex wave functions based on existing laser technology, thereby fostering a novel source for particle and nuclear physics.