Sequentially timed all-optical mapping photography with thin-plate-based spectral broadening for advanced laser ablation system compatibility

Abstract

Sequentially timed all-optical mapping photography (STAMP) is a powerful technique for capturing the poorly reproducible ablation dynamics induced by ultrashort laser pulses. However, its application in ablation visualization is limited by system complexities and the need for a broad probe wavelength band. In this paper, we present a compact STAMP solution employing thin-plate-based spectral broadening, which enables seamless integration into conventional narrowband pump-probe imaging systems for laser ablation. The system is organized into three modules: spectral broadening using a CaF₂ thin plate, pulse stretching with a grating pair or spectrum shuttle, and 2D spectral imaging using a spectral filtering system. This setup allows for the single-shot acquisition of 24-frame sequential images, with a temporal window of up to 400 ps in the 515-nm wavelength band, which corresponds to the second harmonic of Yb-based lasers. The system demonstrated ultrafast imaging of laser ablation in glass using the 800-nm fundamental band of a Ti:sapphire laser for ablation and the 515-nm band generated via optical parametric amplification for probing. Finally, the system applicability to narrow-bandwidth light sources was validated by integrating the packaged STAMP system into a Yb:KGW laser setup and extending the second harmonic’s bandwidth from 5 to 9 nm. The compatibility of this STAMP system with various laser ablation systems opens new avenues for investigating complex ablation dynamics, offering single-shot imaging in a more accessible and versatile format.