Ultrafast camera captures 156 trillion frames per second

26 Mar 2024

INRS single-shot device could reveal details of light-matter interactions and semiconductor behavior.

An ultrafast camera platform developed at Quebec's INRS research center could lead to new views of absorption in semiconductors and deeper understanding of phenomena such as demagnetization of metal alloys.

As described in Nature Communications the device can capture up to 156 trillion frames per second, according to the project team.

The research at the INRS lab of Jinyang Liang builds on the group's previous studies of new approaches to ultrafast photography, including the 2023 development of a diffraction-gated ultrahigh-speed mapping method using optical diffraction as the mechanism for controlling a camera's gating.

For the new device INRS has developed "swept coded aperture real-time femtophotography (SCARF)," a computational imaging modality enabling all-optical ultrafast sweeping of a static aperture during the recording of an ultrafast event.

This contrasts with the more usual ultrafast approach of sequentially capturing frames one by one, acquiring data through brief, repeated measurements and putting those together to subsequently reconstruct the observed movement.

"That approach can only be applied to inert samples or to phenomena that happen the exact same way each time," commented Jinyang Liang. "Fragile samples, not to mention non-repeatable phenomena or phenomena with ultrafast speeds such as femtosecond laser ablation, shock-wave interaction with living cells, and optical chaos, cannot be studied this way."

SCARF is intended in particular to tackle the compromise between sequence depth and field of view imposed on compressed ultrafast photography, limitations attributable to the operating principle of simultaneously shearing the scene and the coded aperture, according to the project.

Low cost and high measurement quality compared to streak cameras

In operation SCARF uses a single linearly chirped laser pulse as a continuous illumination probe, so that each wavelength in the pulse's bandwidth carries a specific timestamp. Two stages of dispersive processing of the returned signal and algorithmic analysis then recreate the dynamic scene being observed.

This approach "enables ultrafast sweeping of a static coded aperture while not shearing the ultrafast phenomenon," commented INRS. "Results can be obtained in a single shot at tunable frame rates and spatial scales in both reflection and transmission modes."

In trials using a SCARF device built from off-the-shelf components, the camera achieved encoding rates of up to 156.3 THz to individual pixels on a CCD camera. It has advantages of low cost and high measurement quality compared to streak camera-based compressed ultrafast photography techniques, noted the INRS team.

Two spin-out companies specializing in ultrafast laser science, Axis Photonique and Few-Cycle, are now working with Jinyang Liang's INRS team to produce a marketable version of the SCARF device and move the technology towards commercialization.

"SCARF makes it possible to observe unique phenomena that are ultrafast, non-repeatable, or difficult to reproduce, such as shock wave mechanics in living cells or matter," said INRS. "These advances could potentially be used to develop better pharmaceutics and medical treatments."