2:45 PM - 3:00 PM
△ [16p-418-7] All-optical Ultrafast 25-frame Burst Imaging using a Frequency-chirped Pulse and Spectral Filtering
Keywords:ultrafast imaging, chirp pulse, single shot
To realize a scaling-flexible STAMP (Sequentially timed all-optical mapping photography) in a simple setup, we modified the system performance of the original STAMP utilizing spectral filtering (SF-STAMP). A newly developed SF-STAMP system consists of a diffractive optical element (DOE), band-pass filter (BPF) array, and two Fourier transform lenses. Using a 25-beam generating DOE, the total number of frames in a single-shot increases up to 25. The BPF arrays select the wavelength ranging from 660 to 810 nm, thus this SF-STAMP system duplicates focused 25-multispectral images simultaneously. Therefore, a linearly frequency-chirped pulse makes spectrally resolved image snapshots with the temporal resolution determined by the BPFs in a temporal window defined by the entire chirped pulse width. The observation time window in a single-shot is variable from sub-picoseconds (10–13 s) to sub-nanoseconds (10–10 s) by varying second-order dispersion added to the laser pulse. In this work, we capture 25-frame burst images of ultrafast crystalline-to-amorphous phase transition with a sub-picosecond resolution using a frequency-chirped pulse broadened from 650 to 900 nm. SF-STAMP method is expected to be a powerful tool for capturing ultrafast phenomena in a single-shot basis within the time window of nanoseconds (10–9 s), which conventional techniques cannot achieve.