Thermal effects on a hexagonal photonic lattice composed circular and triangular rods

Abstract

In this paper, we study the thermal effects on photonic band structures in a hexagonal lattice. We consider that the lattice is composed of GaAs rods embedded in air with circular and triangular cross sections. Using the plane wave expansion method, we found that by increasing the temperature, the contrast of the refractive index increases and causes a shift of the photonic band structures to regions with lower frequencies. By increasing the size of triangular scatterers, the width of the photonic band gap (PBG) for TM polarization increases in comparison with the PBG of the circular scatterers. In addition, we discuss the effects on the band structure when we eliminate the circular and triangular rods in the crystal's lattice. We found that the width of the PBG remains unchanged in the presence of a defective mode inside, which shifts at lower frequencies when the temperature increases. There is evidence of greater radiation confinement in the lattice composed of circular scatterers.