Light Echoes from Linear Filaments

Nemiroff, Robert J.; Zhong, Qi

doi:10.48550/arxiv.1703.05811

Cited by 3 publications

(3 citation statements)

References 28 publications

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“…The apparent "splitting" of superluminal spots from a rotating source was noted in computer animations by Baune [8], while a pair creation event was actually measured in the lab for a plane wave incident on a tilted screen in a bold experiment by Clerici et al [9]. The creation of pair event echoes from a sweeping beam was discussed in detail in Nemiroff [10], and from a flash on a linear reflecting medium by Nemiroff and Zhong [11].…”

Section: Introductionmentioning

confidence: 94%

Pair Events in Superluminal Optics

Nemiroff

2017

Annalen der Physik

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When an object moves faster than emissions it creates, it may appear at two positions simultaneously. The appearance or disappearance of this bifurcation is referred to as a pair event. Inherently convolved with superluminal motion, pair events have no subluminal counterparts. Common examples of superluminal motions that exhibit pair events include Cherenkov radiation, sonic booms, illumination fronts from variable light sources, and rotating beams. The minimally simple case of pair events from a single massive object is explored here: uniform linear motion. A pair event is perceived when the radial component of the object's speed toward the observer drops from superluminal to subluminal. Emission from the pair creation event will reach the observer before emission from either of the two images created. Potentially observable image pair events are described for sonic booms and Cherenkov light. To date, no detection of discrete images following a projectile pair event have ever been reported, and so the pair event nature of sonic booms and Cherenkov radiation, for example, remains unconfirmed. Recent advances in modern technology have made such pair event tracking feasible. If measured, pair events could provide important information about object distance and history.

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Section: Introductionmentioning

confidence: 94%

Pair Events in Superluminal Optics

Nemiroff

2017

Annalen der Physik

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“…the IACT receives Cherenkov light from two locations: from both above and below z C , at the same time. This is the basis for relativistic image doubling (RID) (Nemiroff & Zhong 2017;Nemiroff 2018).…”

Section: Relativistic Image Doubling: Conceptmentioning

confidence: 99%

Toward the Detection of Relativistic Image Doubling in Imaging Atmospheric Cherenkov Telescopes

Nemiroff

Kaushal

2020

ApJ

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Cosmic gamma-ray photons incident on the upper atmosphere create air showers that move to the Earth's surface with superluminal speed, relative to the air. Even though many of these air showers remain superluminal all along their trajectories, the shower's velocity component toward a single Imaging Atmospheric Cherenkov Telescope (IACT) may drop from superluminal to subluminal. When this happens, an IACT that is able to resolve the air shower both in time and angle should be able to document an unusual optical effect known as relativistic image doubling (RID). The logic of RID is that the shower appears to precede its own Cherenkov radiation when its speed component toward the IACT is superluminal, but appears to trail its own Cherenkov radiation when its speed component toward the IACT is subluminal. The result is that the IACT will see the shower start not at the top of the atmosphere but in the middle -at the point along the shower's path where its radial velocity component drops to subluminal. Images of the shower would then be seen by the IACT to go both up and down simultaneously. A simple simulation demonstrating this effect is presented. Clear identification of RID would confirm in the atmosphere a novel optical imaging effect caused not by lenses but solely by relativistic kinematics, and may aid in the accuracy of path and speed reconstructions of the relativistic air shower.

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“…It is also possible to curve the screen and study the transition from superluminal to subluminal propagation. The physics of such a transition for a wavefront has been analysed in detail by Nemiroff and Zhong [111][112][113][114][115], with particular emphasis on the implications for astrophysical observations. The prediction is that at the transition, an image pair will be observed: at the transition for super to subluminal, a pair of images is created at the point for which v y = c whilst image pair annihilation is observed in the opposite case.…”

Section: Time Of Flight Distortions and Relativistic Effectsmentioning

confidence: 99%

A trillion frames per second: the techniques and applications of light-in-flight photography

Faccio

Velten

2018

Rep. Prog. Phys.

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Cameras capable of capturing videos at a trillion frames per second allow to freeze light in motion, a very counterintuitive capability when related to our everyday experience in which light appears to travel instantaneously. By combining this capability with computational imaging techniques, new imaging opportunities emerge such as 3D imaging of scenes that are hidden behind a corner, the study of relativistic distortion effects, imaging through diffusive media and imaging of ultrafast optical processes such as laser ablation, supercontinuum and plasma generation. We provide an overview of the main techniques that have been developed for ultra-high speed photography with a particular focus on 'light-in-flight' imaging, i.e. applications where the key element is the imaging of light itself at frame rates that allow to freeze its motion and therefore extract information that would otherwise be blurred out and lost.

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Light Echoes from Linear Filaments

Cited by 3 publications

References 28 publications

Pair Events in Superluminal Optics

Pair Events in Superluminal Optics

Toward the Detection of Relativistic Image Doubling in Imaging Atmospheric Cherenkov Telescopes

A trillion frames per second: the techniques and applications of light-in-flight photography

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