Electromagnetic oscillations in a multilayer spherical stack

We examine the waveguide properties of a spherical stack: a system of optic al layers deposited onto the microsphere substrate, with arbitrary ratios b etween thicknesses of layers and a wavelength of initial electromagnetic ra diation. Frequency dependencies of the reflection coefficient and impedance of the stack are studied. An appropriate matrix formalism is developed to generalize the matrix method well-known for the plane case, to the case of the spherical layer geometry. The material losses and random deviations of thicknesses of layers are taken into account. The quarter-wave length layer s are studied in details. Our numerical calculations have revealed the narr ow gap of a transparency in a zone of high reflectance of a stack under the suitable parameters. (C) 2000 Published by Elsevier Science B.V. All right s reserved.