Logarithmic ultrafast photography with band-resolved individual delay generation

Ultrafast light–matter interactions span femtosecond-to-nanosecond timescales, yet existing single-shot imaging lacks independently configurable frame allocation across logarithmically separated temporal regimes. Here, we introduce logarithmic ultrafast photography, which distributes a limited number of frames nonuniformly across widely separated temporal regimes. We realize this concept using band-resolved individual delay generation (BRIDGE), which sequentially extracts discrete wavelength bands through angle-dependent filter transmission and assigns each band an independently adjustable free-space delay without dispersive pulse stretching. Implemented in temporal-wavelength-division imaging, BRIDGE generated 11 frames with approximately 260 fs exposure, a minimum interval of 600 fs, and configurable delays of up to 10 ns. We demonstrate its use for surveying ablation dynamics across timescales, revealing that material- and excitation-dependent differences became prominent in the nanosecond regime. In water, logarithmic imaging showed that picosecond excitation strengthened and expanded a localized femtosecond-triggered breakdown response before producing a compact asymmetric shock wave.