Spatio‐Spectral‐Temporal Imaging of Fast Transient Phenomena Using a Random Array of Pinholes

Abstract

Fast transient phenomena such as light–matter interactions, rapid electrical discharge, light scattering in tissues, and biochemical reactions that generate light signatures can be studied using high‐speed cameras. Herein, a lensless, single camera shot, spatio‐spectral‐temporal imaging technique based on chaotic waves is proposed and demonstrated. A random pinhole array is used as a chaotic wave generator to map every color point source in the object space to a unique random distribution. The spatio‐spectral signatures are recorded for two cases using a monochrome high‐speed camera, and an extensive library of spatio‐spectral signatures is synthesized by computational interpolation and extrapolation using the scaling factors of the Fresnel propagators. A spark generated by an abrupt electrical discharge is converted into a chaotic wave using the same pinhole array, and the hologram is recorded using the monochrome high‐speed camera in time. The recorded hologram of the spark is decomposed into spatio‐spectral 4D events in time with a temporal resolution of 40 μs using the semisynthetic spatio‐spectral signatures.

Roadmap on Digital Holography-Based Quantitative Phase Imaging

“…Conventional interferometry has been widely used for quantifying the above events, which we believe are limited by the information bandwidth and are bulky and difficult to implement. In the coming years, we believe that the current methods will be replaced by single shot, elegant, computational optical methods with higher information bandwidth [88,89].…”

“…New imaging techniques based on multidimensional characterization of events changing in 3D volume, time, and spectrum are emerging and can solve previously encountered obstacles of characterization of micro-volumes via pump-probe interferometric techniques [82,86]. With the recent developments in imaging technologies to observe fast transient events in five dimensions [88] and rapidly converging (<5 iterations) phase retrieval approaches [89] using a single camera shot, we believe that it will be possible to obtain additional information about the rapid events occurring in a small volume in space, without the use of bulky time resolved interferometry.…”

Three-dimensional non-destructive visualization of teeth enamel microcracks using X-ray micro-computed tomography

“…Advances in optical microscopy are driven by widespread sophisticated additive manufacturing techniques 24 enabling miniaturization of equipment footprint suitable for minimal invasive procedures 25 . In parallel, multi-modal imaging can be obtained at the same time by acquiring absorbance (dichroism) and birefringence 26 or simultaneus spatio-spectral-temporal mapping 27 . However, to date it has been possible to achieve those results only in the laboratory environment and not in clinical practice.…”

Single-shot spectral-volumetric compressed ultrafast photography

“…Multi-dimensional optical imaging, as a visualization method, can provide information covering the space, time, and spectrum. 1 So far, multi-dimensional optical imaging has played an irreplaceable role in exploring the unknown world and decrypting natural mysteries such as light-matter interactions, 2 light scattering in tissues, 3 and physical or biochemical reactions. [4][5][6] Scanning multi-dimensional optical imaging had to be sequentially operated, and thus its imaging speed was restricted to hundreds of frames per second (fps) due to the limited data readout speed and on-chip storage of chargecoupled devices or complementary metal-oxide semiconductors (CMOSs).…”