Strong field spectroscopy of many-body interactions in solids.

Microscopic dephasing in solid-state high-order harmonic generation is caused by carriers entering regions with enhanced electron-phonon scattering, leading to few-femtosecond coherence times.

• Why it matters: Understanding the origin of ultrafast dephasing is crucial for improving the efficiency and coherence of solid-state quantum light sources, which are limited by this phenomenon.
• What they did: The study combines wavelength-dependent HHG measurements in monolayer and bulk semiconductors with ab initio calculations of electron-phonon scattering and strong-field simulations, incorporating momentum-dependent dephasing.
• The result: The findings show that accurate modeling of HHG yield scaling requires first-principles-derived scattering rates, establishing a microscopic basis for dephasing and enabling strategies to engineer coherence in driven solids.