Accurate and high-speed characterization of transient flow fields is vital for advancing aerospace, combustion, and plasma science. Yet, existing optical and probe-based diagnostics face an inherent trade-off between spatial coverage and temporal resolution, hindering the capture of rapidly evolving phenomena. Here, we introduce ultrafast multipoint flow sensing based on optical time-stretch interferometry, which implements a time-frequency-space mapping to convert spatial distributions into temporal waveforms, enabling simultaneous monitoring of hundreds of points with a spatial resolution of 7.81 μm at a 100 MHz sampling rate. Through absolute phase retrieval, the system quantitatively resolves flow perturbations from ∼10 m/s to ∼300 m/s, achieving root-mean-square deviations of 14.38% and 3.14% compared with hot-wire and Pitot measurements, respectively. Validated against high-speed schlieren imaging, this technique circumvents the long-standing spatiotemporal trade-off, providing a powerful, nonintrusive platform for real-time diagnostics of turbulence, combustion instabilities, and laser–plasma interactions under extreme conditions.
Yu et al. (Mon,) studied this question.