International Journal of Physics | Vol. 4, No. 4, April 2013 | pp. 25–32
DOI: 10.46882/2013/IJP/000036
Research Article
Title: Topological Edge States and Robust Transport in Two-Dimensional Magneto-Optical Photonic Crystals
Names of Authors: J. W. Park¹, S. T. Harrison²
Authors’ Affiliations: ¹Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 34141, South Korea; ²Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, United Kingdom
Abstract: Topological insulators have inspired new avenues for manipulating electromagnetic wave propagation without backscattering losses. This study designs and simulates a two-dimensional magneto-optical photonic crystal exhibiting robust, unidirectional topological edge states. The crystal lattice consists of a triangular array of ferrite rods embedded in an air matrix. It is subjected to an external static magnetic field applied parallel to the rod axes. We calculated the photonic band structure using the finite element method across the microwave spectrum. The application of a 0.3 T magnetic field breaks time-reversal symmetry. This breaking lifts the degeneracy at the Dirac points, opening a topological band gap with a normalized width of Δω/ω0 = 6.5%. We calculated a non-zero Chern number of C = +1 for the lowest bands, confirming the non-trivial topology of the bulk system. To demonstrate transport robustness, we simulated the propagation of an electromagnetic wave packet past sharp corners and large structural defects. The edge mode bypassed these obstacles with a high transmission efficiency of 99.2% ± 0.3%, showing zero backscattering. These findings provide solid engineering guidelines for developing backscattering-immune optical isolators, delay lines, and compact photonic integrated circuits.
Keywords: Topological photonics; edge states; magneto-optical effect; finite element method; Chern number; backscattering immunity
Manuscript Timeline: Received: January 08, 2013; Revised: February 18, 2013; Accepted: March 05, 2013; Published: April 11, 2013
Citation: Park, J. W., & Harrison, S. T. (2013). Topological Edge States and Robust Transport in Two-Dimensional Magneto-Optical Photonic Crystals. International Journal of Physics, 4(4), 25–32.
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