Evaluation of the Temporal Characteristics of Ultrafast Imaging Methods Using Continuous Chirped Pulse Illumination

Ultrafast imaging based on chirped pulse illumination has opened new frontiers, offering a frame rate beyond 1 Tfps for the acquisition of multiple frames in a single-shot. However, the temporal resolving capability is implicitly influenced by parameters in stages of pulse illumination and data acquisition. This study delivers a mathematical model to produce a precise investigation, sorting the dominating factors, including the illumination pulse's bandwidth λFWHM, dispersive propagation length <i>z</i>, and framing module's spectral resolution Δλ. For a different λFWHM, <i>z</i> has a lower bound to ensure the covered signal is resolved; meanwhile, the time resolution decreases with a larger <i>z</i>. Frame extraction with a narrower Δλ leads to a higher time resolution; however, Δλ must be broad enough for a reasonable signal-to-noise ratio. The theoretical and experimental approaches to evaluate temporal characteristics are discussed, enabling a precise quantitative determination for the community to produce, use, and exploit single-shot ultrafast imaging systems.