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About the author
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Publications - PhD thesis - Masters theses |
Research Interests - Photonic Crystals |
This page contains more information about my Ph. D. Thesis titled " Silicon photonic crystals and spontaneous emission ". I have succesfully defended my Ph. D. thesis on April 11 at the University of Utrecht and thus obtained a Ph. D. degree in physics. Below is a picture of the cover of my thesis. There are online versions of my thesis available that you can use. You might access the online version at AMOLF or the online version at the University of Utrecht.
There is a short summary of my thesis that I copied from the University of Utrecht site. For your convenience I have also included a copy of the table of contents, with links to the individual chapters in PDF format that are available from the AMOLF and University of Utrecht website. You have to find out which link works best in terms of download time.
Printed copies of the thesis can be obtained by request via e-mail to library@amolf.nl or by adressing the library at the FOM-Institute for Atomic and Molecular Physics, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands.
Photonic crystals, i.e. materials that have a periodic variation in refractive index, form an
interesting new class of materials that can be used to modify spontaneous emission and
manipulate optical modes in ways that were impossible so far. This thesis is divided in three parts.
Part I discusses the design and fabrication of two-dimensional photonic crystals in silicon using
deep anisotropic etching with a SF6/O2 plasma. The etching process was optimized
for the fabrication of two-dimensional photonic crystals by tuning the main parameters of the etching
process, i.e. temperature, bias voltage and O2 flow. Vertical confinement in these structures is provided
by integrating the structures in a dielectric waveguide. For this purpose, amorphous silicon,
silicon-on-insulator and SiGe structures were considered. Fabrication of structures in both amorphous
silicon and silicon-on-insulator was successfully demonstrated. The incorporation of luminescent species,
such as laser dyes, was demonstrated using a new wet chemical coating technique that forms thin silica
layers on a substrate.
Part II discusses the modification of spontaneous emission in one dimensional systems
by studying the decay rate of luminescing Cr ions close to a dielectric interface. The decay rate of the
Cr ions can be changed by bringing the samples into contact with a range of liquids with different refractive
indices. The change in radiative decay rate can be calculated by calculating the local density of states.
To explain the experimental results additional non-radiative decay channels have to be introduced and yields
a quantum efficiency of ~50% for the Cr R-line luminescence. This concept was further extended to a thin
silica layer on silicon implanted with erbium ions and resulted in the radiative rate of erbium in pure
silica: 54 s-1. This number was used to analyze the decay rate of erbium ions in silica colloidal
spheres that can be used as building block for three-dimensional photonic crystals by self-assembly.
Finally, Part III discusses the optical properties and modified spontaneous emission from a
three-dimensional silicon photonic crystal of finite (5-layers) thickness. The crystals are made in a
layer-by-layer approach using lithographic tools and show near 100% reflection in the 1.4-1.7 µm
wavelength range indicative of a photonic stopgap. A direct comparison with the calculated reflectivity
reveals that some features in the reflectivity can be ascribed to the finite thickness of the crystal,
while other features can be explained in terms of a superstructure that leads to zone folding of
the photonic bandstructure. The collected spontaneous emission from erbium implanted crystals is strongly
reduced for wavelengths in the stopgap from 1.4-1.7 µm. The changes in collected luminescence
intensity are explained in terms of a rate equation model that takes into account the effect
of Bragg scattering, the local density of states and the quantum efficiency of the emitters inside
the crystal. Using this model a spectral attenuation of 5 dB per unit cell at 1.539 µm wavelength is
obtained from the experimental data, which is in perfect agreement with existing theory and transmission data.
Below is the table of contents of my PhD thesis. You can download each individual chapter as a PDF file or you can downlaod the complete thesis as a single PDF file. Each PDF file can be downloaded via the University of Utrecht or the AMOLF website (please use the one that works best for you).
Part I: 2-D
Part II: 1-D
Part III: 3-D
Download the complete thesis as a PDF file from the Utrecht (7634 kB) / AMOLF website
The typesetting of my thesis was done using LaTeX, (a text formatting program). There are a couple of free LaTeX distributions available on the internet that work in a Microsoft Windows environment. I used the MikTeX distribution in combination with the commercial WinEdt editor, which provides me with a graphical user interface for LaTeX commands and a spell checker. If you are new to LaTeX and want to learn more, I recommend the book "a guide to LaTeX" written by Helmut Kopka and Patrick W. Daly.
If you are interested, please download the file sample_thesis.zip (107 kB) which contains the style files thesis.sty and thesis.bst together with a small sample section from my thesis to demonstrate the use of the style files. More information on the use of these files can be found in the sample_thesis.tex file included in the archive. Note: the thesis.sty file requires a number of other standard style files: these can be found and downloaded via the CTAN archive.
If you have any questions or comments about this page, please send
me an e-mail at mdedood@molphys.leidenuniv.nl
Created: August 6, 2002
