Abstract

For capturing ultrafast phenomena in sub-nanosecond (10⁻¹⁰ s) time region in a single-shot basis, we modified STAMP (Sequentially timed all-optical mapping photography) utilizing spectral filtering (SF-STAMP). Our SF-STAMP system consists of a 25-beam-generating diffractive optical element (DOE), a bandpass filter (BPF) or BPF-array, and two Fourier transform lenses. This system duplicates 25-multispectral images simultaneously. Therefore, a linearly frequency-chirped pulse makes spectrally and temporally resolved snapshot-images with the temporal resolution determined by the bandwidth of the wavelength selected by the BPFs. The combination of the DOE and BPF enables to select bandwidth of ~40 nm for each flame, and the BPF-array chooses the entire spectrum ranging from 660 to 810 nm. The observation time window in a single-shot can be tuned from sub-picosecond (10⁻¹³ s) to sub-nanosecond (10⁻¹⁰ s) by controlling the second-order dispersion added to the laser pulse. In this work, we demonstrate 25-frame SF-STAMP system with two-kinds of BPF configuration (a tilted single BPF or BPF-array) and a frequency-chirped laser pulse broadened from 650 to 900 nm. Ultrafast 2D-burst images of crystalline-to-amorphous phase transition of Ge₂Sb₂Te₅ and laser ablation process are captured with sub-picosecond to sub-nanosecond time windows.

© 2017 Optical Society of America