1. Phononic crystals

1.1 General presentation

The original properties of phononic crystals are directly associated with the periodic structure of these artificial materials. The study of wave propagation in periodic structures is a long-standing field of investigation common to various fields of physics. Its origins lie in the work carried out in the late 19th and early 20th centuries, notably by Lord Rayleigh, W.H. and W.L. Bragg, Léon Brillouin and Félix Bloch, on the propagation of waves of various kinds. These include, for example, the study of the propagation of atomic-scale vibrations (known as phonons) in crystalline materials, the diffraction of X-rays or optical waves in solid or liquid media, so-called multilayer or superlattice systems, which are highly prized in the optical and acoustic fields,...