Experimental part of this work dedicated to making a glass metal nanocomposite by
forming silver nanoclusters in an ion-exchanged glass in a hydrogen atmosphere at elevated
temperature followed by an investigation of electric field assisted dissolution of nanoclusters.
The ultimate goal is building a waveguide in glass metal nanocomposite with volume
Bragg grating, i.e. a Bragg grating that runs through the whole cross section of the waveguide.
A new type of phosphate glass, IOG-1 doped by rare earth ions, Er+3 and Y b+3,
designed for integrated optics application, was chosen as a
substrate in this project for
optimal optical properties of such waveguide and prospective active photonic devices.
The grating in a glass metal nanocomposite achieved by means of high DC voltage and
periodically corrugated electrode thus activating electric field assisted dissolution process
predominantly in the regions of a direct contact glass-electrode.
Since wavelength dependent refractive index of a glass metal nanocomposite determined
by its absorption band through Kramers-Kronig relation, tuning parameters of surface
plasmon resonance, related to a charge density oscillations
in metal nanoclusters, controls
the optical properties of glass metal nanocomposite even at a working wavelength of a
waveguide which is far off plasmon resonance. Therefore tuning parameters of the silver
nanoclusters in glass metal nanocomposite leads to optimizing grating contrast.
The rest part of this work concerned with building a computational model of a plasmon
excitation in a waveguide with the coating in the form of periodic nanostructured metal
distribution.
The standard approach used in an antenna theory, a wave equation with the source
term, is applied for solving a
problem of an optical waveguide coated by metal. A computational
model was tested first on a slab waveguide illuminated by fields due to a finite
current source. Then the model was extended to the case of an optical fiber where plasmons are excited by a tilted fiber Bragg grating.
In addition a mode solver for finding complex roots of an optical fiber was developed
to a main model of plasmon excitation. The mode solver is based on a Galerkin wavelet
method.