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arXiv · 1703.01832

Analytical study of mode degeneracy in non-Hermitian photonic crystals with TM-like polarization

Xuefan Yin·Yong Liang·Liangfu Ni·Zhixin Wang·Chao Peng·Zhengbin Li
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Abstract

We present an analytical study of the mode degeneracy in non-Hermitian photonic crystals (PC) with $C_{4v}$ symmetry, from the perspective of the coupled-wave-theory (CWT). The wave couplings and leakages within the non-Hermitian PCs are depicted, and the condition of accidental triple degeneracy is derived which leads to a Dirac-cone like dispersion. We prove that, similar to the real Dirac-cone, the Dirac-cone like band in non-Hermitian PC possesses good linearity and isotropy in the vicinity of the $\Gamma$ point. Moreover, some topological transit of the band may occur when the parameters adiabatically evolve. However, the Berry phase remains zero at the $\Gamma$ point, indicated the Dirac-like-cone dosen't obey Dirac equation and it is only Dirac-cone.

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Xuefan Yin, Yong Liang, Liangfu Ni, Zhixin Wang, Chao Peng, Zhengbin Li. 2017-03-06. Analytical study of mode degeneracy in non-Hermitian photonic crystals with TM-like polarization. https://doi.org/10.1103/physrevb.96.075111

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