In an effort to engineer photonic crystal slab (PCS) devices that operate within a single slab-mode regime, the
effect of increased cladding index was studied using FDTD simulation. It is known that while increased cladding
index forces the light-cone to constrict in frequency, the single mode condition eases allowing for the use of
thicker slabs that remain single-mode. This study shows that the behavior of the photonic band gap is similar to
that of the light-cone, sweeping lower in frequency, and even widening in some cases, as cladding index
increases. Band gap behavior for both even and odd polarizations over thicknesses from d/a = 0.2 to 0.6 and
cladding indices from 1 to 2.5 were studied in efforts to design a single-mode, polarization insensitive, complete
band gap. When graphically overlaid, the light-cone, single-mode condition, and transmission spectra represent
an enabling reference for the design of realizable structures. For device applications where modal dispersion is
detrimental or single mode operation is necessary, a paradigm shift away from air-bridge devices is shown to be
essential as single-mode structures of this type demand slab thicknesses far too thin for adequate band gap engineering.
A complete photonic band gap (PBG) in photonic crystal slab (PCS) devices is desirable for various applications, and a
realizable device of this kind demands minimal transmittance in-plane as well as out of plane. While in the past much
work has considered this problem, none have held transverse confinement as a prime factor. In order to achieve our
goal, square and triangular hole shapes are considered. Looking at sharp featured shapes as well as their fabrication
realizable rounded counterparts and an even more rudimentary triangular cluster of circles, we look to break the crystalmode
symmetries for TM photonic bands and, therefore, open a complete band gap between the 1st and 2nd bands for
both TE and TM light. TE/TM gap overlap is optimized for single-slab-mode operation, via the effective index method,
for hole size, hole orientation, and slab thickness - all as functions of the lattice constant, a, and operational wavelength, λ. It is found that rounded triangular holes and tri-clustered circular holes of size 0.88a and thickness d/λ = 0.112 show identical photonic behavior that provides an optimized gap overlap of 0.0496 (ωa/2πc = a/λ) with a 12.81% gap figure of merit (Δω/ω0).
Applications for photonic integrated circuit technologies based on the conditional Faraday Effect with electron spins in
quantum dots are discussed. The interaction of light with the quantum confined electrons leads to a rotation of the light
polarization. Design considerations for polarization multiplexing systems and plasmon resonance sensors based on
polarization rotation are presented. Calculations for light of wavelengths λ=1.3 μm and λ=1.55 μm show devices with
active regions of a few hundred microns are possible using InAs/GaAs quantum dots. The advantages of spin-based
devices are also discussed.
A comprehensive theoretical analysis of the cavity quantum electrodynamics (QED) in single-photon Mach-Zehnder
Interferometer (SMZI) based switches and single quantum gates that are intended for the processing of quantum
information encoded in the polarization of single photons inside integrated photonic crystal (PC) quantum networks is
presented. These devices rely on manipulating the geometrical phase of single photons by means of the Single-Photon
Faraday Effect (SPFE), which can be described in terms of a detuned single mode quantum field strongly interacting
with a two-level system or quantum dot (QD) inside nanocavities. The feasibility of such devices depends on the ability
for the field in each arm of the interferometer to couple in their respective nanocavities, successfully interact with the
quantum dot, and when the appropriate phase is accumulated couple out; all these steps being performed with minimum
phase error and losses. Using the Jaynes-Cummings model, the cavity dynamics is studied for various detuning energies
and coupling energies, and it is shown that the design of these devices can achieve low phase error and robustness
against fabrication errors.
GaAs-based PIN detectors with mesa sizes 1, 2.5, 5, 7.5 and 10 mm were fabricated and characterized for alpha particle
response using a Po-210 alpha source. By decoupling the neutron conversion process of a proximity moderator, we were
able to directly probe the alpha response characteristics of the PIN detectors as a function of device area. Dark current
levels in the PIN detectors ranged from 6.1 to 9.5 pA at zero bias. The dark current values were higher for larger devices
and a linear relationship between mesa size and dark current was observed. The PIN detectors were found to have a
strong alpha response of up to 5 nA/mm2 with a linear relation between the response current and mesa area. The
measured responsivity of the detectors was 0.014 A/W. The average device efficiency was determined to be 31.5%.
Using the measured alpha response properties of the GaAs PIN diodes one is able to select the optimal device area for a
given moderator and application specific neutron flux.
Multi-photon three-dimensional micro-/nano-fabrication (3DM) is a powerful technique for creating complex 3D micro-scale structures of the type needed for micro-electromechanical systems (MEMS), micro-optics, and microfluidics. In 3DM high peak-power laser pulses are tightly focused into a medium which undergoes a physical or chemical change following multi-photon excitation at the focal point. Complex structures are generated by serial 3D-patterned exposure within the material volume. To further the application of 3DM to micro-component engineering, we are developing a fully automated and integrated 3DM system capable of creating complex cross-linked polymer structures based on patterns designed in a CAD environment. The system consists of four major components: (1) a femtosecond laser and opto-mechanical system; (2) 3-axis micro-positioner; (3) a computer-controlled fabrication interface; and (4) software for fabrication-path planning. The path-planning software generates a 3DM command sequence based on an object-design input file created using standard commercial CAD software. The 3DM system can be used for start-to-finish design and fabrication of waveguides, 3D photonic crystals, and other complex micro-structures. These results demonstrate a technological path for implementing 3DM as a tool for micro- and nano-optical component manufacture.