Abstract
We study, theoretically and experimentally, optical properties of different types of honeycomb photonic structures, known also as “photonic graphene.” First, we employ the two-photon polymerization method to fabricate the honeycomb structures. In the experiment, we observe a strong diffraction from a finite number of elements, thus providing a unique tool to define the exact number of scattering elements in the structure with the naked eye. Next, we study theoretically the transmission spectra of both honeycomb single layer and two-dimensional (2D) structures of parallel dielectric circular rods. When the dielectric constant of the rod materials is increasing, we reveal that a 2D photonic graphene structure transforms into a metamaterial when the lowest Mie gap opens up below the lowest Bragg band gap. We also observe two Dirac points in the band structure of 2D photonic graphene at the point of the Brillouin zone and demonstrate a manifestation of Dirac lensing for the TM polarization. The performance of the Dirac lens is that the 2D photonic graphene layer converts a wave from point source into a beam with flat phase surfaces at the Dirac frequency for the TM polarization.
1 More- Received 30 March 2017
DOI:https://doi.org/10.1103/PhysRevA.95.063837
©2017 American Physical Society
Physics Subject Headings (PhySH)
Focus
Image—Honeycomb Diffraction
Published 23 June 2017
Predictions of diffraction patterns for honeycomb photonic crystals were part of a comprehensive study of these structures that may be useful in nanoscale photonic devices.
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