Single-shot optical imaging with spectrum circuit bridging timescales in high-speed photography

Authors

Takao Saiki, Keitaro Shimada, Ayumu Ishijima, Hang Song, Xinyi Qi, Yuki Okamoto, Ayako Mizushima, Yoshio Mita, Takuya Hosobata, Masahiro Takeda, Shinya Morita, Kosuke Kushibiki, Shinobu Ozaki, Kentaro Motohara, Yutaka Yamagata, Akira Tsukamoto, Fumihiko Kannari, Ichiro Sakuma, Yuki Inada, and Keiichi Nakagawa

Abstract
Single-shot optical imaging based on ultrashort lasers has revealed nonrepetitive processes in subnanosecond timescales beyond the recording range of conventional high-speed cameras. However, nanosecond photography without sacrificing short exposure time and image quality is still missing because of the gap in recordable timescales between ultrafast optical imaging and high-speed electronic cameras. Here, we demonstrate nanosecond photography and ultrawide time-range high-speed photography using a spectrum circuit that produces interval-tunable pulse trains while keeping short pulse durations. We capture a shock wave propagating through a biological cell with a 1.5-ns frame interval and 44-ps exposure time while suppressing image blur. Furthermore, we observe femtosecond laser processing over multiple timescales (25-ps, 2.0-ns, and 1-ms frame intervals), showing that the plasma generated at the picosecond timescale affects subsequent shock wave formation at the nanosecond timescale. Our technique contributes to accumulating data of various fast processes for analysis and to analyzing multi-timescale phenomena as a series of physical processes.

Science Advances: https://www.science.org/doi/10.1126/sciadv.adj8608