Efficient generation of isolated attosecond pulses with high beam quality by two-color Bessel-Gauss beams

The generation of isolated attosecond pulses with high efficiency and high beam quality is essential for attosecond spectroscopy. We numerically investigate the supercontinuum generation in a neutral rare-gas medium driven by a two-color Bessel-Gauss beam. The results show that an efficient smooth supercontinuum in the plateau is obtained after propagation and the spatial profile of the generated attosecond pulse is Gaussian-like with the divergence angle of 0.1° in the far-field. This bright source with high beam quality is beneficial for detecting and controlling the microscopic processes on attosecond time scale.