Thu, 03 Jun 2010
16:30 -
17:30
DH 1st floor SR
Structured media with defects: asymptotic models and localisation
Alexander Movchan
(University of Liverpool)
Abstract
Bloch Floquet waves are considered in structured media. Such waves are dispersive and the dispersion diagrams contain stop bands. For an example of a harmonic lattice, we discuss dynamic band gap Green’s functions characterised by exponential localisation. This is followed by simple models of exponentially localised defect modes. Asymptotic models involving uniform asymptotic approximations of physical fields in structured media are compared with homogenisation approximations.