2004/05/13 by A. Ardavan, Arzhang Ardavan, John Singleton +12
Engineering · Materials Science · Physics and Astronomy · #FOS: Physical sciences #Metamaterials and Metasurfaces Applications #Optics (physics.optics) #Orbital Angular Momentum in Optics #Space Physics (physics.space-ph) #Terahertz technology and applications #physics.optics #physics.space-ph
paper · pdf · doi:10.48550/arxiv.physics/0405062
23 pages, 12 figures
arxiv created 2004/05/13 · openalex publication_date 2004/05/13 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We describe the experimental implementation of a superluminal (\it i.e. faster than light \it in vacuo) polarization current distribution that both oscillates and undergoes centripetal acceleration. Theoretical treatments lead one to expect that the radiation emitted from each volume element of such a polarization current will comprise a Čerenkov-like envelope with two sheets that meet along a cusp. The emission from the experimental machine is in good agreement with these expectations, the combined effect of the volume elements leading to tightly-defined beams of a well-defined geometry, determined by the source speed and trajectory. In addition, over a restricted range of angles, we detect the presence of cusps in the emitted radiation. These are due to the detection over a short time period (in the laboratory frame) of radiation emitted over a considerably longer period of source time. Consequently, the intensity of the radiation at these angles was observed to decline more slowly with increasing distance from the source than would the emission from a conventional antenna. The angular distribution of the emitted radiation and the properties associated with the cusps are in good \it quantitative agreement with theoretical models of superluminal sources once the effect of reflections from the earth's surface are taken into account.