Acoustic Poisson-like effect in periodic structures

Localization of acoustic modes in periodic porous silicon structures

The propagation of longitudinal acoustic waves in multilayer structures based on porous silicon and the experimental measurement of acoustic transmission for the structures in the gigahertz range are reported and studied theoretically. The considered structures exhibit band gaps in the transmission spectrum and these are localized modes inside the band gap, coming from defect layers introduced ...

Study of Surface Acoustic Waves under Periodic Grating Structures

-The propagation characteristics of the surface acoustic waves (SAW) propagating under the periodic metal grating on ST-cut quartz substrates were theoretically investigated in order to achieve more accurate design of the devices. The theoretical method used here is based on Floquet’s theorem using the space harmonics method (SHM) as an orthogonal function set. The boundary conditions are satis...

Finite-Difference Time-Domain Simulation of Light Propagation in 2D Periodic and Quasi-Periodic Photonic Structures

Ultra-short pulse is a promising technology for achieving ultra-high data rate transmission which is required to follow the increased demand of data transport over an optical communication system. Therefore, the propagation of such type of pulses and the effects that it may suffer during its transmission through an optical waveguide has received a great deal of attention in the recent years. We...

The Cherenkov Effect in Graphene-Like Structures

Toric Poisson Structures

Let TC be a complex algebraic torus and let X(Σ) be a complete nonsingular toric variety for TC. In this paper, a real TCinvariant Poisson structure ΠΣ is constructed on the complex manifold X(Σ), the symplectic leaves of which are the TC-orbits in X(Σ). It is shown that each leaf admits an effective Hamiltonian action by a subtorus of the compact torus T ⊂ TC. However, the global action of TC ...