Compressive ultrahigh-speed imaging based on acousto-optic frequency sweeping

Ultrahigh-speed imaging is an essential tool for capturing fast dynamic scenes across various fields. Despite the development of numerous technical strategies, achieving ultrahigh-speed imaging with high spatiotemporal resolution and substantial sequence depth remains a significant challenge. To address this issue, we present a compressive ultrahigh-speed imaging technique based on acousto-optic frequency sweeping, termed AOFS-CUSI. AOFS-CUSI employs light with rapidly time-varying spectra generated by acousto-optic modulation to illuminate dynamic scenes, records spatio-spectral information using snapshot compressive imaging, and ultimately reconstructs spatiotemporal information through time-spectrum mapping. This technique achieves a temporal resolution of 1.55 million frames per second, a spatial resolution of 228 lp/mm, and a sequence depth of 31 in a single shot. We experimentally validate the superior performance of AOFS-CUSI by capturing the rotation of an optical chopper, the movement of microspheres in a microchannel, and the femtosecond-laser-induced cavitation bubble dynamics. By eliminating the requirement for ultrafast laser sources and simultaneously extending the temporal window, AOFS-CUSI offers an excellent solution for recording and analyzing various fast dynamics, presenting significant potential for applications in both fundamental and applied research.