Band engineering method to create Dirac cones of accidental degeneracy in general photonic crystals without symmetry.

  title={Band engineering method to create Dirac cones of accidental degeneracy in general photonic crystals without symmetry.},
  author={Hongchen Chu and Yang Zhang and Jie Luo and Changqing Xu and Xiang Xiong and Ruwen Peng and Mu Wang and Yun Lai},
  journal={Optics express},
  volume={29 12},
Symmetry usually plays a key role in the formation of the Dirac cone in the band structure of triangular or hexagonal systems. In this work, we demonstrate a systematic method to create Dirac cones of accidental degeneracy in general photonic crystals without symmetry. With this method, a band gap can be closed gradually through a series of modification to the unit structure based on the eigenfields of the band edges, and consequently a Dirac point is formed with Dirac conical dispersions in… 
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