AI 中文总结
本研究利用相位分辨太赫兹时域光谱，观测到GaAs/Al₀.₃₆Ga₀.₆₄As二维电子气中朗道极化激元的拉比振荡延迟一个腔往返时间启动，揭示了太赫兹频段杂化光-物质态的动力学特征。
AI 中文摘要
强光-物质耦合通过电磁腔场与物质激发之间的相干周期性能量交换产生极化激元。尽管这种相互作用通常可从光谱模式分裂推断，但其动力学仍在很大程度上未被探索。本文中，我们利用相位分辨太赫兹时域光谱，观测到GaAs/Al₀.₃₆Ga₀.₆₄As二维电子气中的回旋共振与法布里-珀罗腔模耦合形成的朗道极化激元的拉比振荡。通过采用交叉偏振光谱和磁场微分技术，我们解析出回旋共振振荡的时域拍频。值得注意的是，我们发现拉比振荡并非在回旋共振被激发后立即启动，而是在对应一个腔往返时间的延迟后才出现。这表明强耦合 regime 仅在腔模场形成后才建立。我们的结果为太赫兹频段杂化光-物质态的动力学提供了直接的见解。
英文摘要
Strong light-matter coupling gives rise to polaritons through coherent and periodic energy exchange between electromagnetic cavity fields and material excitations. While this interaction is typically inferred from spectral mode splitting, its dynamics remain largely unexplored. Here, using phase-resolved terahertz time-domain spectroscopy, we observe Rabi oscillations of Landau polaritons formed by coupling the cyclotron resonance in a GaAs/Al$_{0.36}$Ga$_{0.64}$As two-dimensional electron gas with Fabry-Perot cavity modes. By employing cross-polarized spectroscopy and magnetic-field differential, we resolve the temporal beating of the cyclotron resonance oscillations. Remarkably, we find that the Rabi oscillations do not start immediately after excitation of the cyclotron resonance, but after a delay corresponding to one cavity round-trip time. This demonstrates that the strong-coupling regime sets up only after the formation of the cavity mode field. Our results provide direct insight into the dynamics of hybrid light-matter states in the THz regime.
