Electron Excitation Probability in Dielectrics under Two-color Intense Laser Fields

Abstract: Two-color laser fields offer significantly enhanced control over electron excitation dynamics under ultrashort intense laser pulses compared to monochromatic fields. However, their strong nonlinearity necessitates computationally expensive first-principles calculations to accurately predict ionization dynamics. To overcome this challenge, we derive an analytical expression for the ionization rate in dielectrics subjected to intense two-color laser fields, refining the theoretical framework introduced in JPSJ {\bf 88}, 024706 (2019). By benchmarking our formula against first-principles calculations based on time-dependent density functional theory (TDDFT) for $\alpha$-quartz, we demonstrate that our model captures the essential physics of ionization dynamics with remarkable qualitative accuracy, despite employing certain approximations. This analytical approach not only provides deeper physical insight but also offers a computationally efficient alternative for predicting strong-field interactions in dielectrics.