Efficient generation of Bessel-Gauss attosecond pulse trains via nonadiabatic phase-matched high-order harmonics
Mingxuan Li, Xiangyu Tang, Huiyong Wang, Jialong Li, Wentao Wang, Jun Cai, Jieda Zhang, Xinyue San, Xinning Zhao, Pan Ma, Sizuo Luo, Cheng Jin, Dajun Ding
Abstract
Generating Bessel-Gauss beams in the extreme ultraviolet (EUV) with attosecond pulse durations poses a significant challenge due to the limitations of conventional transmission optical components. Here, we propose a novel approach to produce such beams by inducing an annular EUV source through high-order harmonic generation (HHG) under nonadiabatic phase-matching conditions. The resulting light pulse maintains temporal coherence and manifests attosecond pulse trains as confirmed by the reconstruction of attosecond beating by interference of two-photon transitions (RABBIT) measurements. Macroscopic HHG calculations reproduce the measured spatiotemporal structures, demonstrating the plasma-induced spatial modulation on the formation of an annular source. Propagation simulations further confirm the feasibility of this approach for generating attosecond Bessel-Gauss beams, presenting exciting prospects for various applications in EUV photonics and attosecond science.