Controlling isolated attosecond pulse generation in MoSe₂ using polarization gating and TDDFT simulations

The dependence of high harmonic generation spectra in solids on the driving wavelength remains an open question, especially regarding its impact on the generation of isolated attosecond pulses. Achieving active control over isolated attosecond pulse generation remains challenging due to the complex dynamics underlying solid-state high harmonic generation. In this work, we investigate high harmonic generation and the corresponding attosecond pulses generated from monolayer molybdenum diselenide using a real-time, ab initio time-dependent density functional theory approach. Our results reveal a linear increase in harmonic cutoff energy with driving wavelength, both parallel and perpendicular to the laser polarization direction. Using a polarization gating technique with symmetric amplitude components, we evaluate attosecond pulse isolation across multiple wavelengths and identify 2.5 [Formula: see text] as the most favorable for generating clean isolated attosecond pulses. Momentum-resolved electron dynamics reveal conditions that favor isolated pulse formation at 2.5 [Formula: see text]. Furthermore, by applying an asymmetric polarization gating at this optimal wavelength, isolated attosecond pulses with favorable temporal confinement are achieved. This study provides insight into wavelength-dependent control of high harmonic generation and efficient isolated attosecond pulse generation in solids.