Attosecond pulse generation from Weyl semimetals

The generation of attosecond pulses from higher-order harmonics is an essential milestone toward enabling time-resolved spectroscopy of electronic processes in matter on the attosecond timescale. The avenue for high-harmonic generation from solids has proliferated since its discovery a decade ago. However, isolated attosecond pulse generation from solids remains scarce. We report a theoretical proposal that leverages Weyl semimetals for highly efficient attosecond pulse generation in the far-ultraviolet region. The generation of isolated attosecond pulses from Weyl semimetals is achieved using two-color laser pulses, which generate a broad higher-harmonic plateau ranging from 3 to 11 eV. Attosecond pulses with comparable durations – spanning approximately 500 to 900 as – are generated in both collinear and orthogonal configurations of the two-color fields. The strength and duration of the attosecond pulses can be optimized by tailoring the polarization direction and relative strength of the two-color field.