Dual Phononic And Photonic Band Gaps In A Periodic Array Of Pillars Deposited On A Membrane

Y. Pennec, Y. El Hassouani, C. Li, B.D. Rouhani, E.H. El Boudouti, H. Larabi, and A. Akjouj
Institut d’Electronique, de Microélectronique et de Nanotechnologie, Université de Lille, Villeneuve d’Ascq, France

Phononic crystals are a class of materials that exhibit periodic variations in their density and elastic properties. Such crystals modify the propagation of acoustic waves and prohibit the propagation of sound for frequencies within the band gap. We discuss the simultaneous existence of phononic and photonic band gaps in a periodic array of silicon pillars deposited on a homogeneous SiO2 membrane. We investigate in detail several lattices, namely square, triangular, and hexagonal using the Finite Element calculations in COMSOL Multiphysics and a developed Plane Wave Expansion method.