Fiber guiding at the Dirac frequency beyond photonic bandgaps


Light trapping within waveguides is a key practice of modern optics, both scientifically and technologically. Photonic crystal fibers traditionally rely on total internal reflection (index-guiding fibers) or a photonic bandgap (photonic-bandgap fibers) to achieve field confinement. Here, we report the discovery of a new light trapping within fibers by the so-called Dirac point of photonic band structures. Our analysis reveals that the Dirac point can establish suppression of radiation losses and consequently a novel guided mode for propagation in photonic crystal fibers. What is known as the Dirac point is a conical singularity of a photonic band structure where wave motion obeys the famous Dirac equation. We find the unexpected phenomenon of wave localization at this point beyond photonic bandgaps. This guiding relies on the Dirac point rather than total internal reflection or photonic bandgaps, thus providing a sort of advancement in conceptual understanding over the traditional fiber guiding. The result presented here demonstrates the discovery of a new type of photonic crystal fibers, with unique characteristics that could lead to new applications in fiber sensors and lasers. The Dirac equation is a special symbol of relativistic quantum mechanics. Because of the similarity between band structures of a solid and a photonic crystal, the discovery of the Dirac-point-induced wave trapping in photonic crystals could provide novel insights into many relativistic quantum effects of the transport phenomena of photons, phonons, and electrons.

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Divisions: College of Engineering & Physical Sciences > Aston Institute of Photonics Technology (AIPT)
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Uncontrolled Keywords: Band structure,Dirac equation,Optical fiber,Optical mode,Photonic crystal,Electronic, Optical and Magnetic Materials,Atomic and Molecular Physics, and Optics
Publication ISSN: 2047-7538
Last Modified: 08 Jul 2024 17:26
Date Deposited: 14 Oct 2019 11:55
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Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
https://www.nat ... icles/lsa201577 (Publisher URL)
PURE Output Type: Article
Published Date: 2015-06-19
Authors: Xie, Kang
Zhang, Wei (ORCID Profile 0000-0002-3584-8541)
Boardman, Allan D.
Jiang, Haiming
Hu, Zhijia (ORCID Profile 0000-0002-8960-5318)
Liu, Yong
Xie, Ming
Mao, Qiuping
Hu, Lei
Li, Qian
Yang, Tianyu
Wen, Fei
Wang, Erlei



Version: Published Version

License: Creative Commons Attribution

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