The dynamical Franz-Keldysh effect, indicative of the transient light-matter interaction regime between quantum and classical realms, is widely recognized as an essential signature in wide bandgap condensed matter systems such as dielectrics. In this theoretical study, we applied time-resolved transient absorption spectroscopy to investigate ultrafast optical responses in graphene, a zero-bandgap system. We observed in the gate-tuned graphene that the massless Dirac materials notably enhance intraband light-driven transitions, significantly leading to the giant dynamical Franz-Keldysh effect compared to the massive Dirac materials, a wide bandgap system. In addition, employing the angle-resolved spectroscopy, it is found that the unique polarimetry orientation, i.e., perpendicular polarizations for the pump and the probe, further pronounces the optical spectra to exhibit the complete fishbone structure, reflecting quantum pseudospin natures of Dirac cones. Our findings expand the establishment of emergent transient spectroscopy frameworks into not only zero-bandgap systems but also pseudospin-mediated quantum phenomena, moving beyond dielectrics.

动力学 Franz-Keldysh 效应表明量子和经典领域之间的瞬态光-物质相互作用机制，被广泛认为是电介质等宽带隙凝聚态系统的基本特征。在这项理论研究中，我们应用时间分辨瞬态吸收光谱来研究石墨烯（一种零带隙系统）中的超快光学响应。我们在门调谐石墨烯中观察到，与大块 Dirac 材料（一种宽带隙系统）相比，无质量的 Dirac 材料显着增强了带内光驱动跃迁，显着导致了巨大的动力学 Franz-Keldysh 效应。此外，采用角度分辨光谱，发现独特的偏振方向，即泵和探针的垂直偏振，进一步使光谱表现出完整的鱼骨结构，反映了 Dirac 锥的量子伪自旋性质。我们的研究结果将新兴瞬态光谱框架的建立扩展到零带隙系统，还包括伪自旋介导的量子现象，超越了电介质。