Effective method to identify and verify the Dirac-like point through finite photonic crystals with triangular lattice

¹ College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences Beijing 100049, China
² Department of Optics, Shandong University - Jinan 250100, China
³ State Key Laboratory of Information Photonics and Optical Communications & School of Science, Beijing University of Posts and Telecommunications - Beijing 100876, China

^(a) gydong@ucas.ac.cn

Received: 8 March 2017
Accepted: 9 May 2017

Abstract

The precise location of the Dirac-like point of a finite photonic crystal array with a triangular lattice can be identified easily from the transmittance spectrum of any output interface with the characteristic of a sharp cusp embedded in the extremum spectrum near the Dirac-like point. The transmission properties of the finite triangular lattice photonic crystal arrays with square and hexagonal shapes have been investigated systematically to demonstrate that the transmittance at the Dirac-like point has a close relation with the output interface feature of the photonic crystal array and the output interfaces with the same feature will bring about the uniform transmission characteristics in different directions. These results provide us with a more accurate and convenient method to identify the Dirac-like point of a photonic crystal with different lattice structures, array sizes and shapes, and give guidelines for its use in experiments.