Tailored nanostructures can confine electromagnetic waveforms in extremely sub-wavelength volumes, opening new avenues in lightwave sensing and control down to sub-molecular resolution. Atomic light–matter interaction depends critically on the absolute strength and the precise time evolution of the near field, which may be strongly influenced by quantum-mechanical effects. However, measuring atom-scale field transients has remained out of reach. Here we introduce quantitative atomic-scale waveform sampling in lightwave scanning tunnelling microscopy to resolve a tip-confined near-field transient. Our parameter-free calibration employs a single-molecule switch as an atomic-scale voltage standard. Although salient features of the far-to-near-field transfer follow classical electrodynamics, we develop a comprehensive understanding of the atomic-scale waveforms with time-dependent density functional theory. The simulations validate our calibration and confirm that single-electron tunnelling ensures minimal back-action of the measurement process on the electromagnetic fields. Our observations access an uncharted domain of nano-opto-electronics where local quantum dynamics determine femtosecond atomic near fields.

量身定制的纳米结构可以将电磁波形限制在极小的亚波长范围内，从而为光波传感开辟了新途径，并可以控制至亚分子分辨率。原子的光-质相互作用主要取决于近场的绝对强度和精确的时间演化，这可能会受到量子力学效应的强烈影响。但是，测量原子级场瞬变仍然遥不可及。在这里，我们在光波扫描隧道显微镜中引入定量的原子级波形采样，以解决尖端受限的近场瞬变问题。我们的无参数校准采用单分子开关作为原子级电压标准。尽管远场转移的显着特征遵循经典的电动力学原理，我们使用随时间变化的密度泛函理论对原子级波形进行了全面的理解。这些模拟验证了我们的校准，并确认单电子隧穿确保了测量过程对电磁场的最小反作用。我们的观察结果访问了纳米光电的一个未知领域，其中局部量子动力学决定了飞秒原子的近场。