High harmonic generation in crystal SiO2 by sub-10-fs laser pulses

The high harmonic generation (HHG) by few-cycle laser pulses is essential for research in strong-field solid-state physics. Through comparison of high harmonic spectra of solids generated by laser pulses with varying durations, we discovered that lasers with good dispersion compensation are capable of producing a broad spectrum of high harmonics. As the pulse duration is further compressed, several interference peaks appear in the broad spectrum. Moreover, we conducted simulations using the semiconductor Bloch equation, considering the effect of Berry curvature, to better understand this process. Our work provides a valuable approach for studying HHG by few-cycle laser pulses in solid materials, expanding the application of HHG in attosecond physics.