| Summary: | This thesis presents designs and fabrication algorithms for 3D photonic band
gap (PBG) material synthesis and embedded optical waveguide networks.
These designs are suitable for large scale micro-fabrication using
optical lithography methods.
The first of these is a criss-crossing pore structure based on fabrication
by direct photo-electrochemical etching in single-crystal silicon.
We demonstrate that a modulation of the pore radius between pore crossing
points leads to a moderately large PBG.
We delineate a variety of PBG architectures
amenable to fabrication by holographic lithography.
In this technique, an optical interference pattern exposes a
photo-sensitive material, leading to a template structure in the
photoresist whose dielectric-air interface
corresponds to an iso-intensity surface in the exposing interference pattern.
We demonstrate PBG architectures obtainable from the interference
patterns from four independent beams.
The PBG materials may be fabricated by replicating the developed photoresist
with established silicon replication methods.
We identify optical beam configurations that optimize the intensity contrast
in the photoresist.
We describe the invention of a new approach to holographic lithography
of PBG materials using the diffraction of light through
a three-layer optical phase mask (OPM).
We show how the diffraction-interference pattern resulting from
single beam illumination of our OPM
closely resembles a diamondlike architecture for suitable designs of the
phase mask.
It is suggested that OPML may both simplify and supercede all previous
optical lithography approaches to PBG material synthesis.
Finally, we demonstrate theoretically the creation of three-dimensional
optical waveguide networks in holographically defined PBG materials.
This requires the combination of direct laser writing (DLW) of lines
of defects within the holographically-defined photoresist and the replication
of the microchip template with a high refractive index semiconductor
such as silicon.
We demonstrate broad-band (100-200~nm), single-mode waveguiding in air,
based on the light localization mechanism of the PBG as well as sharp
waveguide bends in three-dimensions with minimal backscattering.
This provides a basis for broadband 3D integrated optics in holographically
defined optical microchips.
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