Diffraction-gated real-time ultrahigh-speed mapping photography

Abstract

Single-shot high-speed mapping photography is a powerful tool used for studying fast dynamics in diverse applications. Despite much recent progress, existing methods are still strained by the trade-off between sequence depth and light throughput, errors induced by parallax, limited imaging dimensionality, and the potential damage caused by pulsed illumination. To overcome these limitations, we explore time-varying optical diffraction as a new gating mechanism to obtain ultrahigh imaging speed. Inspired by the pulse front tilt-gated imaging and the space-time duality in optics, we embody the proposed paradigm in the developed diffraction-gated real-time ultrahigh-speed mapping (DRUM) photography. The sweeping optical diffraction envelope generated by the inter-pattern transition of a digital micromirror device enables sequential time-gating at the sub-microsecond level. DRUM photography can capture a transient event in a single exposure at 4.8 million frames per second. We apply it to the investigation of femtosecond laser-induced breakdown in liquid and laser ablation in biological samples.

Coded optical streaking for ultrahigh-speed imaging

“…This synergy enables ultrahigh-speed imaging over a two-dimensional field of view in real time. This imaging paradigm can be embodied by using various optical components, achieving imaging speeds from hundreds to trillions of frames per second [4][5][6][7].…”

Tutorial on compressed ultrafast photography

“…First, the spatial encoding and temporal shearing operations allow a mixture of information between time and space, which enables CUP to have a large sequence depth (i.e., the number of frames in each recorded movie) compared with other single-shot ultrafast imaging systems based on spatial frequency multiplexing, 21 – 24 spectral filtering, 25 – 30 and beam splitting. 31 – 34 Meanwhile, it overcomes the limitations in sensing dimension in conventionally regarded one-dimensional (1D) high-speed sensors. 14 , 35 Compared with ultrafast CCD sensors that have a low fill factor, CUP uses spatiotemporal multiplexing to effectively enhance the light throughput in data acquisition, which improves the feasibility of image reconstruction.…”

“…In contrast, the multiple-shot methods can only collect information from a column (from point scanning) or a slice (from line scanning) of the datacube. 41 Meanwhile, distinguished from single-shot framing (or mapping) photography, 30,34,42 CUP maintains time continuity in data acquisition, which further enhances the amount of acquirable information. 18 Because of its unprecedented imaging ability, CUP immediately became a research focus since its invention.…”