Group Velocities and Resonance State in Metallic Photonic Crystals

• Published in: 2018 Progress in Electromagnetics Research Symposium (PIERS-Toyama) pp. 2511 - 2515
• Main Authors: Low, K. L., Mat Jafri, M. Z., Khan, Sohail A.
• Format: Conference Proceeding
• Language: English
• Published: The Institute of Electronics, Information and Communication Engineers (IEICE) 01.08.2018
• Subjects: Dielectric constant; Photonic crystals; Photonics; Plasmons; Surface waves
• ISSN: 2694-5053
• DOI: 10.23919/PIERS.2018.8597741

Recently, band structure graphs for frequency-dependent materials have been analysed by several researchers. The main aim is searching for possible metamaterials in the different frequency range. In this work, the band structure graph for H polarization mode of dielectric rods' relative permittivity from 1 to 5 has been plotted for the visible frequency range. We assumed that the metallic medium exhibit in Drude model and the band structure graph is plotted with plane wave expansion method. The graphs are used to describe and understand some unique phenomena, which include the surface plasmon effect and negative group velocities of photonic crystals. The frequency region that we are investigating is around plasma frequency of metal. In this range, the metal can behave like free electron gas model when higher than it or opaque to wave when is lower. We found that the waves can propagate with negative group velocities in the direction Γ (0, 0) to X (π/a, 0) in some of the dielectric rods when is lower than the plasma frequency. Then, wave's group velocities contours for the waves inside the dielectric rods has been plotted and analysed. We found that the surface plasmon effect caused the waves to resonate inside the dielectric rods. The resonance state of the wave can cause resonance in other dielectric rods and cause to propagate inside the metallic medium of photonic crystal.