Attosecond transient absorption resolves the instantaneous response of a quantum system as it interacts with a laser field, by mapping its sub-cycle dynamics onto the absorption spectrum of attosecond pulses. However, the quantum dynamics are imprinted in the amplitude, phase and polarization state of the attosecond pulses. Here we introduce attosecond transient interferometry and measure the transient phase, as we follow its evolution within the optical cycle. We demonstrate how such phase information enables us to decouple the multiple quantum paths induced in a light-driven system, isolating their coherent contribution and retrieving their temporal evolution. Applying attosecond transient interferometry reveals the Stark shift dynamics in helium and retrieves long-term electronic coherences in neon. Finally, we present a vectorial generalization of our scheme, theoretically demonstrating the ability to isolate the underlying anomalous current in light-driven topological materials. Our scheme provides a direct insight into the interplay of light-induced dynamics and topology. Attosecond transient interferometry holds the potential to considerably extend the scope of attosecond metrology, revealing the underlying coherences in light-driven complex systems.

阿秒瞬态吸收通过将量子系统的子周期动力学映射到阿秒脉冲的吸收光谱上，解决了量子系统与激光场相互作用时的瞬时响应。然而，量子动力学被印在阿秒脉冲的振幅、相位和极化状态中。在这里，我们介绍了阿秒瞬态干涉测量法并测量瞬态相位，因为我们跟踪了它在光学周期内的演变。我们展示了这种相位信息如何使我们能够解耦光驱动系统中诱导的多个量子路径，隔离它们的相干贡献并检索它们的时间演化。应用阿秒瞬态干涉测量法揭示了氦气中的 Stark 位移动力学，并检索了氖气中的长期电子相干性。最后，我们提出了方案的矢量泛化，从理论上证明了在光驱动拓扑材料中隔离潜在异常电流的能力。我们的方案提供了对光诱导动力学和拓扑相互作用的直接见解。阿秒瞬态干涉测量法有可能大大扩展阿秒计量的范围，揭示光驱动复杂系统中的潜在相干性。