Compressive Imaging Beyond One Trillion Frames Per Second

Johns Hopkins University, Baltimore MD

Investigators

Abstract

This research program will develop a video imaging system operating at frame rates beyond one trillion frames per second and that is capable of recording isolated (non-repetitive) events. No current camera technology can operate at these extremely high frame rates and video durations for the observation of isolated events. The primary challenges for such a technology are the short time-gating and high light irradiance necessary to achieve fast exposure times with extremely high frame rate and the massive information bandwidth associated with such high-speed image acquisition. Such a high-speed single-shot imaging system is an enabling technology for numerous applications throughout engineering and the physical and life sciences. In particular, we plan to leverage the ultrafast single-shot imager developed through this program to better understand the dynamics of materials under extreme conditions. This research can positively impact society from a health and safety perspective through better understanding of the effect of impacts on materials and thus facilitate the development of materials that can better control and prevent injuries to the human body. In addition, through this research program we plan to offer undergraduate research experiences, provide the project data and experimental system for educational purposes such as class design projects and hands-on lab demonstrations, and further our participation in outreach activities for young students from severely underrepresented groups within the engineering discipline. The primary goal of this research program is to develop and experimentally validate a photonic imaging system employing compressed sensing (CS) for video acquisition at frame rates well beyond a terahertz (THz). Our approach leverages the dimensionality reduction afforded by CS to reconstruct three-dimensional spatio-temporal video information from a single high resolution two-dimensional image captured by a camera. Thereby, the measurement efficiency of CS will also mitigate the traditional challenge of the acquisition of a large amount of image data in an extremely short amount of time. Furthermore, our approach is built upon a temporal Fourier processor using a time-lens to imprint the temporal scene dynamics onto an ultrafast laser pulse's spectrum allowing for capture of three-dimensional spatio-temporal video information using a hyperspectral CS camera architecture. This time-lens approach fully leverages the available optical bandwidth maximizing both the frame rate and the number of frames captured in a single exposure. We aim to reach frame rates beyond 1 THz and record lengths of more than 100 frames. No current technology can achieve this combination of performance, yet such a technology can be revolutionary for understanding of ultrafast physical phenomena. Specifically, such single-shot imaging is necessary for observing isolated events such as destructive, rare, and/or costly events and is extremely challenging on ultrafast time-scales. Through this research program we will develop this imager, investigate methods for increasing image contrast, and begin to explore its application to the understanding of material failure under extreme conditions.