All-optical spatiotemporal oscilloscope for few-cycle optical waveform

The advancement of ultrafast science necessitates diagnostic techniques capable of higher precision and increased dimensionality for few-cycle pulses. As pulses continue to shorten temporally and broaden spectrally, the temporal and spatial components become inseparable. Consequently, many established techniques fall short of accurately diagnosing both the temporal and spatial characteristics of pulses. We propose an all-optical spatiotemporal oscilloscope to comprehensively characterize the waveform of few-cycle pulses. By introducing a spatiotemporal perturbing pulse to influence high-harmonic(HH)generation, the frequency of the radiating HHs oscillates with variations in the delay between the pulses. This spatially dependent frequency oscillation of the HHs enables the reconstruction of the temporal and spatial details of the perturbing pulse. This method provides a straightforward and reliable strategy for multidimensional waveform characterization of few-cycle pulses, with potential applications in probing ultrafast dynamical processes carrying spatiotemporal information.