Precise identification of Dirac-like point through a finite photonic crystal square matrix.

Guoyan Dong,Xiulun Yang,Xiangfeng Meng,Ji Zhou

doi:10.1038/srep36712

Guoyan Dong, Xiulun Yang + Show 2 more

Open Access

https://doi.org/10.1038/srep36712

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Abstract

The phenomena of the minimum transmittance spectrum or the maximum reflection spectrum located around the Dirac frequency have been observed to demonstrate the 1/L scaling law near the Dirac-like point through the finite ribbon structure. However, so far there is no effective way to identify the Dirac-like point accurately. In this work we provide an effective measurement method to identify the Dirac-like point accurately through a finite photonic crystal square matrix. Based on the Dirac-like dispersion achieved by the accidental degeneracy at the centre of the Brillouin zone of dielectric photonic crystal, both the simulated and experimental results demonstrate that the transmittance spectra through a finite photonic crystal square matrix not only provide the clear evidence for the existence of Dirac-like point but also can be used to identify the precise location of Dirac-like point by the characteristics of sharp cusps embedded in the extremum spectra surrounding the conical singularity.

Highlights

The phenomena of the minimum transmittance spectrum or the maximum reflection spectrum located around the Dirac frequency have been observed to demonstrate the 1/L scaling law near the Dirac-like point through the finite ribbon structure
Since the accidental degeneracy of two dipolar modes and a single monopole mode generates at the Dirac-like point (DLP), the linear dispersions of Dirac cone can occur at the Brillouin zone center of PhCs18–23
TM2 and TM4 bands cross each other linearly at the Brillouin zone center Γto form a Dirac cone intersected by the additional flat TM3 band at the degenerate point, i.e. DLP

Summary

Introduction

The phenomena of the minimum transmittance spectrum or the maximum reflection spectrum located around the Dirac frequency have been observed to demonstrate the 1/L scaling law near the Dirac-like point through the finite ribbon structure. The dispersion properties obeying the 1/L scaling law near the DP or DLP in the normal propagation direction have been verified theoretically and experimentally[21,26,27] through the dielectric PhC ribbons with the finite thicknesses, which come from the conically shaped dispersion and the transmission as a function of frequency with an extremum near the conical singularity[8,26].

Results

Conclusion