Researchers at East China Normal University have developed a new imaging technique that captures ultrafast events in trillionths of a second, revealing both brightness and structural changes in a single shot. The method, called compressed spectral-temporal coherent modulation femtosecond imaging (CST-CMFI), tracks phenomena like plasma formation and electron movement. Yunhua Yao, the team leader, described it as a major advance for physics, chemistry, and materials science.
At the Extreme Optical Imaging Laboratory of East China Normal University, scientists have created CST-CMFI, a breakthrough in single-shot ultrafast imaging. This technique combines time-spectrum mapping, compressive spectral imaging, and coherent modulation imaging to record both light intensity and phase information from events unfolding in hundreds of femtoseconds. A chirped laser pulse links time to wavelength, and a physics-informed neural network reconstructs the data into a sequence of frames, forming an ultrafast movie from one exposure. Yunhua Yao, the research team leader, explained: 'Our new technique can capture the complete evolution of both the brightness and internal structure of an object in a single measurement.' The team published their work in Optica. Tests demonstrated the method on plasma generated in water by a femtosecond laser pulse, showing brightness and phase changes in the plasma channel, including dense free-electron formation. They also observed carrier dynamics in ZnSe, detecting subtle phase variations even without intensity changes. Yao noted: 'Phase measurements can be much more sensitive than intensity measurements in detecting subtle ultrafast processes.' Yao highlighted potential applications in high-power lasers for clean energy, advanced manufacturing, efficient electronics, and solar cells. The team plans to study interface dynamics and ultrafast phase transitions, and to integrate CST-CMFI with compressive ultrafast photography for broader use.
