A deeper understanding of absorption in semiconductors and of phenomena such as demagnetization of metal alloys is afforded by a new ultrafast camera platform. The device developed by an international group of researchers can capture up to 156 trillion frames per second.
The analytical advance builds on progress in ultrafast photography technology, including the recent development of a diffraction-gated ultrahigh-speed mapping method using optical diffraction as the mechanism for controlling a camera's gating. The new system incorporates 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 differs from the conventional ultrafast approach of sequentially capturing frames one by one, acquiring data through brief, repeated measurements and assembling them to reconstruct the observed movement.
The researchers explain that SCARF is engineered 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. The system 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.
During tests with off-the-shelf components, the camera achieved encoding rates of up to 156.3 THz to individual pixels on a CCD camera. The comparatively low-cost device described in Nature Communications provides high measurement quality compared to streak camera-based compressed ultrafast photography techniques.
Researchers from the Chinese Academy of Sciences, University of Quebec (Canada), Université de Lorraine (France) and Huazhong University of Science and Technology (China) contributed to this development.
