A certain class of photonic crystals with conical dispersion is known to behave as isotropic zero-refractive-index medium. However, the discrete building blocks in such photonic crystals are limited to construct multidirectional devices, even for high-symmetric photonic crystals. Here, we show multidirectional emission from low-symmetric photonic crystals with semi-Dirac dispersion at the zone center. We demonstrate that such low-symmetric photonic crystal can be considered as an effective anisotropic zero-refractive-index medium, as long as there is only one propagation mode near Dirac frequency. Four kinds of Dirac multidirectional emitters are achieved with the channel numbers of five, seven, eleven, and thirteen, respectively. Spatial power combination for such kind of Dirac directional emitter is also verified even when multiple sources are randomly placed in the anisotropic zero-refractive-index photonic crystal.
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Nature Publishing Group
Nature Scientific Reports
Automated multi-modal tomography for sub-22nm IC nodes
This work was funded by the The Netherlands Organisation for Scientific Research (NWO); grant id nwo/13314 - Automated multi-modal tomography for sub-22nm IC nodes
Scientific Computing

He, X, Zhong, Y, Zhou, Y, Zhong, Z, & Dong, J. (2015). Dirac directional emission in anisotropic zero refractive index photonic crystals. Nature Scientific Reports, 5. doi:10.1038/srep13085