Measuring transient optical fields is pivotal not only for understanding ultrafast phenomena but also for the quantitative detection of various molecular species in a sample. Here we demonstrate near-petahertz electric field detection of a few femtosecond pulses with 200 attosecond temporal resolution and subfemtojoule detection sensitivity. By field-resolved detection of the impulsively excited molecules in the liquid phase, termed femtosecond fieldoscopy, we demonstrate temporal isolation of the response of the target molecules from those of the environment and the excitation pulse. In a proof-of-concept analysis of aqueous and liquid samples, we demonstrate field-sensitive detection of combination bands of 4.13 μmol ethanol for the first time. This method expands the scope of aqueous sample analysis to higher detection sensitivity and dynamic range, while the simultaneous direct measurements of phase and intensity information pave the path towards high-resolution biological spectro-microscopy.

测量瞬态光场不仅对于理解超快现象至关重要，而且对于定量检测样品中的各种分子种类也至关重要。在这里，我们演示了几个飞秒脉冲的近 PB 赫兹电场检测，具有 200 阿秒的时间分辨率和亚飞焦耳检测灵敏度。通过对液相中脉冲激发的分子进行场分辨检测，称为飞秒场镜检查，我们证明了目标分子的响应与环境和激发脉冲的响应的时间隔离。在水性和液体样品的概念验证分析中，我们首次展示了对 4.13 μmol 乙醇组合条带的场敏检测。该方法将水性样品分析的范围扩展到更高的检测灵敏度和动态范围，同时直接测量相位和强度信息，为高分辨率生物光谱显微镜铺平了道路。