Quantum calculations of tunneling in strong-field ionization predict intricate momentum distributions due to sub-laser-cycle attosecond electron dynamics. These are obscured in most experiments by the dominance of intercycle interference patterns, which are the hallmark of above-threshold ionization (ATI). Highly controlled one- to two-cycle laser pulses produce less intercycle interference but cannot accurately recreate the subcycle features produced by uniform-cycle calculations due to the effect of the carrier envelope of the pulse. We present a simple and effective technique to recover these subcycle features in experimental multicycle spectra. We time-filter the momentum distribution to highlight features originating from the interference of electron trajectory pairs with ionization times less than one field cycle apart. This method removes the ATI patterns and reveals subcycle interference structures in detail. We can resolve modulations in holographic structures that provide a reference for comparing with calculations.

中文翻译：

---

解开强场电离中的亚周期电子动量谱

强场电离中隧穿的量子计算可预测由于次激光周期阿秒电子动力学而导致的复杂动量分布。在大多数实验中，这些都被周期间干扰模式的优势所掩盖，这是阈值以上电离（ATI）的标志。受到严格控制的一到两个周期的激光脉冲产生的周期间干扰较小，但由于脉冲的载波包络的影响，无法准确地重现均匀周期计算所产生的子周期特征。我们提出了一种简单有效的技术来恢复实验多周期光谱中的这些亚周期特征。我们对动量分布进行时间滤波，以突出显示源自电离时间小于一个场周期的电子轨迹对干扰的特征。此方法删除了ATI模式，并详细揭示了子周期干扰结构。我们可以解析全息结构中的调制，为与计算进行比较提供参考。