Accidental degeneracy in a photonic crystal consisting of a square array of elliptical dielectric cylinders leads to both a semi-Dirac point at the center of the Brillouin zone and an electromagnetic topological transition (ETT). A perturbation method is deduced to affirm the peculiar linear-parabolic dispersion near the semi-Dirac point. An effective medium theory is developed to explain the simultaneous semi-Dirac point and ETT and to show that the photonic crystal is either a zero-refractive-index material or an epsilon-near-zero material at the semi-Dirac point. Drastic changes in the wave manipulation properties at the semi-Dirac point, resulting from ETT, are described.©2014 Optical Society of America.
|Original language||English (US)|
|State||Published - Jan 21 2014|
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The author is grateful to Prof. Z.Q. Zhang, Prof. C.T. Chan, Prof. J. Li, Prof. J. Mei and Dr. X.Q. Huang for fruitful discussions. Special thanks go to Prof. P. Sheng, Prof. Y. Lai, and Prof. Z.H. Hang for their comments. I also would like to acknowledge insightful comments from anonymous reviewers, which greatly helped to improve the quality of this paper. I thank V. Unkefer for editorial work on this manuscript. This work was supported by KAUST Baseline Research Funds.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics