2026-10-01 東京大学
広い時間領域をつなぐ対数的高速撮度影法の概念図
＜関連情報＞
- https://www.t.u-tokyo.ac.jp/press/pr2026-10-01-002
- https://opg.optica.org/optica/fulltext.cfm?uri=optica-13-10-2028
バンド分解された個別の遅延生成による対数超高速撮影 Logarithmic ultrafast photography with band-resolved individual delay generation
Keitaro Shimada, Kohei Azuma, Jun Horiuchi, Dylan Thomas, Masato Ota, and Keiichi Nakagawa
Optica Published: September 25, 2026
DOI:https://doi.org/10.1364/OPTICA.610944
Abstract
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.
