Eur. Phys. J. D (2015) 69: 273
https://doi.org/10.1140/epjd/e2015-60478-7

Regular Article

Correlation of optical reflectivity with numerical calculations for a two-dimensional photonic crystal designed in Ge

¹ National Institute of Materials Physics, Atomistilor 105b, 077125 Magurele-Ilfov, Romania
² National Institute for Laser, Plasma & Radiation Physics, Atomistilor 409, 077125 Magurele, Romania
³ University of Bucharest, Faculty of Physics, Atomistilor 405, 077125 Magurele, Romania

^a e-mail: dana.popescu@infim.ro

Received: 20 August 2015
Received in final form: 5 October 2015
Published online: 10 December 2015

Abstract

A two dimensional photonic crystal (2DPhC) with triangular symmetry is investigated using optical reflectivity measurements and numerical calculations. The system has been obtained by direct laser writing, using a pulsed laser (λ = 775 nm), perforating an In-doped Ge wafer. A lattice of holes with well-defined symmetry has been designed. Analyzing the spectral signature of PBGs recorded experimentaly with finite difference time domain theoretical calculations one was able to prove the relation between the geometric parameters (hole format, lattice constant) of the system and its ability to trap and guide the radiation in specific energy range. It was shown that at low frequency and telecommunication ranges of transvelsal electric modes photonic band gap occur. This structure may have potential aplications in designing photonic devices with applications in energy storage and conversion as potential alternative to Si-based technology.