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1
Yi, Yasha 1974. "On-chip silicon based photonic structures : photonic band gap and quasi-photonic band gap materials". Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/29457.
Resumen
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2004."June 2004."
Includes bibliographical references (leaves 170-180).
This thesis focuses on integrated silicon based photonic structures, photonic band gap (PBG) and quasi-photonic band gap (QPX) structures, which are based on high refractive index contrast dielectric layers and CMOS compatibility. We developed a new type of silicon waveguide - Photonic Crystal (PC) cladding waveguide is studied based on PBG principle. The refractive index in the new PC cladding waveguide core therefore has a large flexibility. Low index core (e.g. SiO2) or hollow core waveguide can be realized with our PC cladding waveguide structure. The fabrication of the waveguide is compatible to CMOS process. To demonstrate the PBG guiding mechanism, we utilized prism coupling to the Asymmetric PC cladding waveguide and the effective index of the propagation mode is measured directly. The measured effective mode index is less than both Si and Si3N4 cladding layers, which is clear demonstration of the photonic band gap guiding principle. We also fabricated and measured the PC cladding channel waveguide. Potential applications include high power transmission, low dispersion, thin cladding thickness and nonlinear properties engineering. Secondly, we developed a Si-based multi-channel optical filter with tunability, which is based on omnidirectional reflecting photonic band gap structure with a relatively large air gap defect. Using only one device, multi channel filter with tunability around two telecom wavelength 1.55[mu]m and 1.3[mu]m by electrostatic force is realized. Four widely spaced resonant modes within the photonic band gap are observed, which is in good agreement with numerical simulations.
(cont.) The whole process is compatible with current microelectronics process technology. There are several potential applications of this technology in wavelength division multiplexing (WDM) devices. Thirdly, to further extend the photonic crystal idea, we studied the quasi-photonic crystal structures and their properties, especially for the fractal photonic band gap properties and the transparent resonant transmission states. A-periodic Si/SiO2 Thue-Morse (T-M) multilayer structures have been fabricated, for the first time, to investigate both the scaling properties and the omnidirectional reflectance at the fundamental optical band-gap. Variable angle reflectance data have experimentally demonstrated a large reflectance band-gap in the optical spectrum of a T-M quasicrystal, in agreement with transfer matrix simulations. The physical origin of the T-M omnidirectional band-gap has been explained as a result of periodic spatial correlations in the complex T-M structure. The unprecedented degree of structural flexibility of T-M systems can provide an attractive alternative to photonic crystals for the fabrication of photonic devices.
by Yasha Yi.
Ph.D.
2
Almén, Fredrik. "Band structure computations for dispersive photonic crystals". Thesis, Linköping University, Department of Science and Technology, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-9610.
Resumen
Photonic crystals are periodic structures that offers the possibility to control the propagation of light.
The revised plane wave method has been implemented in order to compute band structures for photonic crystals. The main advantage of the revised plane wave method is that it can handle lossless dispersive materials. This can not be done with a conventional plane wave method. The computational challenge is comparable to the conventional plane wave method.
Band structures have been calculated for a square lattice of cylinders with different parameters. Both dispersive and non-dispersive materials have been studied as well as the influence of a surface roughness.
A small surface roughness does not affect the band structure, whereas larger inhomogeneities affect the higher bands by lowering their frequencies.
3
Castiglicone, Dario Calogero. "Block copolymer based photonic band gap materials". Thesis, University of Reading, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501328.
Resumen
A photonic crystal is any material which exhibits a photonic band gap (PBG) and is comprised of a periodic arrangement of alternating layers of different dielectric constant. It has been found recently that an interesting route to approach such materials is via the synthesis of block copolymers which are able to microphase separate. This thesis describes the synthetic methods, in particular anionic polymerization, used to prepare such copolymers which exhibit photonic properties in the visible region of the electromagnetic spectrum.
4
Maldovan, Martin. "Exploring for new photonic band gap structures". Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/30121.
Resumen
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2004.Includes bibliographical references (leaves 103-104).
In the infinite set of possible photonic band gap structures there are no simple rules to serve as a guide in the search for optimal designs. The existence and characteristics of photonic band gaps depend on such factors as dielectric contrast, volume fraction, symmetry and connectivity of the dielectric structure. In this thesis a large set of photonic structures are developed to help understand the nature of the dependencies and provide a platform for easy fabrication of three-dimensional structures with large complete photonic band gaps. Two approaches for accessing new structures are examined. A systematic method based on crystallography to search for photonic band gap structures is established in this thesis. A search within the FCC space groups is undertaken resulting in the discovery of two new photonic band gap structures. Specific structures found in self-organizing systems, the single P, the single G, and single D structures, are shown to possess large photonic band gaps. Design guidelines to fabricate these structures by interference lithography are given. A layer-by-layer approximation of the single D structure amenable to fabrication by conventional semiconductor fabrication techniques is proposed. A second technique for obtaining photonic band gap structures with different topologies is based on the splitting of nodes in the diamond network. The realization of these structures using block copolymer self assembly and layer-by-layer lithographic technique are briefly examined.
by Martin Maldovan.
Ph.D.
5
Yamashita, Tsuyoshi. "Unraveling photonic bands : characterization of self-collimation in two-dimensional photonic crystals". Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-06072005-104606/.
Resumen
Thesis (Ph. D.)--School of Materials Science and Engineering, Georgia Institute of Technology, 2006.Summers, Christopher, Committee Chair ; Chang, Gee-Kung, Committee Member ; Carter, Brent, Committee Member ; Wang, Zhong Lin, Committee Member ; Meindl, James, Committee Member ; Li, Mo, Committee Member.
6
Burr, Justin R. "Degenerate Band Edge Resonators in Silicon Photonics". The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1449233730.
7
Lancaster, Greg A. "A Tunable Electromagnetic Band-gap Microstrip Filter". DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/952.
Resumen
In high frequency design, harmonic suppression is a persistent struggle. Non-linear devices such as switches and amplifiers produce unwanted harmonics which may interfere with other frequency bands. Filtering is a widely accepted solution, however there are various shortcomings involved. Suppressing multiple harmonics, if desired, with traditional lumped element and distributed component band-stop filters requires using multiple filters. These topologies are not easily made tunable either. A new filter topology is investigated called Electromagnetic Band-Gap (EBG) structures.
EBG structures have recently gained the interest of microwave designers due to their periodic nature which prohibits the propagation of certain frequency bands. EBG structures exhibit characteristics similar to that of a band-stop filter, but in periodically repeating intervals making it ideal for harmonic suppression. The band-gap frequency of an EBG structure may be varied by altering the periodicity of the structure. However, EBG materials are generally static in structure making tuning a challenge.
In this thesis, a novel solution for tuning the band-gap properties of an EBG structure is investigated. Designs aimed to improve upon existing solutions are reached. These designs involve acoustic and mechanical tuning methods. Performance is simulated using Agilent’s Advanced Design System (ADS) and a device is constructed and evaluated. Comparing all measured test cases to simulation, band-gap center frequency error is on average 4.44% and absolute band-gap rejection error is 1.358 dB.
8
Whitehead, Debra Elayne. "Photonic band gap systems based on synthetic opals". Thesis, University of Salford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.402126.
9
Nanni, Emilio A. (Emilio Alessandro). "A 250 GHz photonic band gap gyrotron amplifier". Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/82364.
Resumen
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 191-206).
This thesis reports the theoretical and experimental investigation of a novel gyrotron traveling-wave-tube (TWT) amplifier at 250 GHz. The gyrotron amplifier designed and tested in this thesis has achieved a peak small signal gain of 38 dB at 247.7 GHz, with a 32 kV, 0.35 A electron beam and a 8.9 T magnetic field. The instantaneous -3 dB bandwidth of the amplifier at peak gain is 0.4 GHz. A peak output power of 45 W has been measured. The output power is not saturated but is limited by the 7.5 mW of available input power. The amplifier can be tuned for operation from 245- 256 GHz. With a gain of 24 dB and centered at 253.25 GHz the widest instantaneous -3 dB bandwidth of 4.5 GHz was observed for a 19 kV, 0.305 A electron beam. To achieve stable operation at these high frequencies, the amplifier uses a novel photonic band gap (PBG) interaction circuit. The PBG interaction circuit confines the TE₀₃-like mode which couples strongly to the electron beam. The PBG circuit provides stability from oscillations by supporting the propagation of TE modes in a narrow range of frequencies, allowing for the confinement of the operating TE₀₃-like mode while rejecting the excitation of oscillations at lower frequencies. Experimental results taken over a wide range of parameters, 15-30 kV and 0.25-0.5 A, show good agreement with a theoretical model. The theoretical model incorporates cold test measurements for the transmission line, input coupler, PBG waveguide and mode converter. This experiment achieved the highest frequency of operation (250 GHz) for a gyrotron amplifier. At present, there are no other amplifiers in this frequency range that are capable of producing either high gain or high-output power. With 38 dB of gain and 45 W this is also the highest gain observed above 94 GHz and the highest output power achieved above 140 GHz by any conventional-voltage vacuum electron device based amplifier. The output power, output beam pattern, instantaneous bandwidth, spectral purity and shot-to-shot stability of the amplified pulse meet the basic requirements for the implementation of this device on a pulsed dynamic nuclear polarization (DNP) nuclear magnetic resonance (NMR) spectrometer.
by Emilio A. Nanni.
Ph.D.
10
Smirnova, Evgenya I. "Novel photonic band gap structures for accelerator applications". Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32294.
Resumen
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2005."June 2005."
Includes bibliographical references (p. 181-184).
In this thesis I present the design and experimental demonstration of the first photonic band gap (PBG) accelerator at 17.140 GHz. A photonic band gap structure is a one-, two- or three-dimensional periodic metallic and/or dielectric system (for example, of rods), which acts like a filter, reflecting rf fields in some frequency range and allowing rf fields at other frequencies to transmit through. Metal PBG structures are attractive for the Ku-band accelerators, because they can be employed to suppress wakefields. Wakefields are unwanted modes affecting the beam propagation or even destroying the beam. Suppression of wakefields is important. In this thesis, the theory of metallic PBG structures is explained and the Photonic Band Gap Structure Simulator (PBGSS) code is presented. PBGSS code was well benchmarked and the ways to'benchmark the code are described. Next, the concept of a PBG resonator is introduced. PBG resonators were modelled with Ansoft HFSS code, and a single-mode PBG resonator was designed. The HFSS design of a travelling-wave multi- cell PBG structure was performed. The multicell structure was built, cold-tested and tuned. Finally, the hot-test PBG accelerator demonstration was performed at the accelerator laboratory. The PBG accelerating structure was installed inside a vacuum chamber on the Haimson Research Corporation (HRC) accelerator beam line and powered with 2 MW from the HRC klystron. The electron bunches were produced by the HRC accelerator. The electron beam was accelerated by 1.4 MeV inside the PBG structure.
by Evgenya I. Smirnova.
Ph.D.
11
Chen, Jerry C. (Jerry Chia-yung). "Electromagnetic field computation and photonic band gap devices". Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/11293.
Resumen
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.Includes bibliographical references (p. 147-166).
by Jerry Chia-yung Chen.
Ph.D.
12
Marsh, Roark A. "Experimental study of photonic band gap accelerator structures". Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/52788.
Resumen
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references (p. 181-186).
This thesis reports theoretical and experimental research on a novel accelerator concept using a photonic bandgap (PBG) structure. Major advances in higher order mode (HOM) damping are required for the next generation of TeV linear colliders. In this work, PBG HOMs are studied theoretically and experimentally for the first time. PBG HOMs are shown in simulation to be low Q lattice modes, removed from the cavity defect and beam position. Direct wakefield measurements were made in hot test using the bunch train produced by the MIT HRC 17 GHz linear accelerator. Measurements are compared with beam-loading theory, and wakefield simulations using ANALYST. Excellent agreement is observed between theory predictions and power measured in the 17 GHz fundamental operating mode; reasonable agreement is also seen with the 34 GHz wakefield HOM. In order to understand the performance of PBG structures under realistic high gradient operation, an X-band (11.424 GHz) PBG structure was designed for high power testing in a standing wave breakdown experiment at SLAC. The PBG structure was hot tested to gather breakdown statistics, and achieved an accelerating gradient of 65 MV/m at a breakdown rate of two breakdowns per hour at 60 Hz, and accelerating gradients above 110 MV/m at higher breakdown rates. High pulsed heating occurred in the PBG structure, with many shots above 270 K, and an average of 170 K for 35x10⁶ shots. Damage was observed in both borescope and scanning electron microscope imaging.
(cont.) No breakdown damage was observed on the iris surface, the location of peak electric field, but pulsed heating damage was observed on the inner rods, the location of magnetic fields as high as 1 MA/m. Breakdown in accelerator structures is generally understood in terms of electric field effects. PBG structure results highlight the unexpected role of magnetic fields on breakdown. The hypothesis is presented that the low level electric field on the inner rods is enhanced by pulsed heating surface damage, and causes breakdown. A new PBG structure was designed with improved pulsed heating, and will be tested. These results greatly further the understanding of advanced structures with wakefield suppression that are necessary for future colliders.
by Roark A. Marsh.
Ph.D.
13
Wood, Michael G. "Active Silicon Photonic Devices Based on Degenerate Band Edge Resonances". The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1480432902683812.
14
Aközbek, Neset. "Optical solitary waves in a photonic band gap material". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0007/NQ35096.pdf.
15
Vats, Nipun. "Non-Markovian radiative phenomena in photonic band-gap materials". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/NQ63758.pdf.
16
Norton, Richard. "Numerical computation of band gaps in photonic crystal fibres". Thesis, University of Bath, 2008. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501623.
Resumen
Photonic crystal fibres are capable of special light guiding properties that ordinary optical fibres do not possess, and efforts have been made to numerically model these properties. The plane wave expansion method is one of the numerical methods that has been used. Unfortunately, the function that describes the material in the fibre n(x) is discontinuous, and convergence of the plane wave expansion method is adversely affected by this. For this reason, the plane wave expansion method may not be every applied mathematician’s first choice method but we will show that it is comparable in implementation and convergence to the standard finite element method. In particular,an optimal preconditioner for the system matrix A can easily be obtained and matrixvector products with A can be computed in O(N logN) operations (where N is the size of A) using the Fast Fourier Transform. Although we are always interested in the efficiency of the method, the main contribution of this thesis is the development of convergence analysis for the plane wave expansion method applied to 4 different 2nd-order elliptic eigenvalue problems in R and R2 with discontinuous coefficients. To obtain the convergence analysis three issues must be confronted: regularity of the eigenfunctions; approximation error with respect to plane waves; and stability of the plane wave expansion method. We successfully tackle the regularity and approximation error issues but proving stability relies on showing that the plane wave expansion method is equivalent to a spectral Galerkin method, and not all of our problems allow this. However, stability is observed in all of our numerical computations. It has been proposed in [40], [53], [63] and [64] that replacing the discontinuous coefficients in the problem with smooth coefficients will improve the plane wave expansion method, despite the additional error. Our convergence analysis for the method in[63] and [64] shows that the overall rate of convergence is no faster than before. To define A we need the Fourier coefficients of n(x), and sometimes these must be approximated, thus adding an additional error. We analyse the errors for a method where n(x) is sampled on a uniform grid and the Fourier coefficients are computed with the Fast Fourier Transform. We then devise a strategy for setting the grid-spacing that will recover the convergence rate of the plane wave expansion method with exact Fourier coefficients.
17
Zhang, JieXi. "Experimental studies of hybrid photonic band gap accelerator structures". Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/103230.
Resumen
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 2016.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 211-217).
This thesis reports the first high power tests of a hybrid photonic band gap (PBG) accelerator structure. PBG structures can support a single electromagnetic mode, thus damping higher-order modes (HOMs) generated by wakefields. We have designed, built and successfully tested a 17.14 GHz hybrid PBG (HPBG) structure containing both dielectric and metallic elements. Dielectric elements have low loss and the potential to survive high surface electromagnetic fields. The HPBG structure was constructed as a triangular lattice array with sapphire rods inside and copper rods outside sandwiched between copper plates. The lattice parameter and the rod pattern were adjusted to excite a high-Q TM0 2 mode and to suppress HOMs. This overmoded operation is a unique and novel feature of the hybrid design. The design included the birefringence of sapphire. Simulations showed relatively high surface fields at the triple point where sapphire, copper and vacuum meet as well as in any gaps between components in the clamped assembly. Three structures were tested with later structures designed to sequentially reduce the surface electric field. The third structure used sapphire rods with pin extensions at each end and obtained the highest gradient of 19 MV/m, corresponding to a surface E field of 78 MV/m, with a breakdown probability of 5 x 10 1 /pulse/m in 45-ns pulses. Operation above 20 MV/m gradient led to runaway breakdowns with extensive light emission and eventual damage. For all three structures, multipactor light emission was observed at gradients well below the breakdown threshold. Breakdown damage was found at the triple point where surface fields peaked. The deposition of copper onto sapphire resulting from breakdowns might eventually degrade the cavity quality. This research indicated that multipactor triggered at the triple point limited the operational gradient of the hybrid structure. These experiments represent the first high power tests of a hybrid PBG structure. The gradient achieved of 19 MV/m is the highest achieved with a dielectric structure. The gradient was found to be limited by multipactor and breakdown. The overmoded cavity with relatively large beam apertures might still find applications at high frequency or in high current transmission.
by JieXi Zhang.
Ph. D.
18
Hu, Qichao. "Synthesis of electromagnetic modes in photonic band gap fibers". Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40896.
Resumen
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2007.Includes bibliographical references (leaves 66-67).
In this paper, we report on the successful synthesis of three individual modes, HE11, TEo0, and TE02 for transmission in photonic band gap fibers at near infrared wavelengths. We measure the propagation losses of the HE11 and TE01 modes both inside and outside the band gap of the fiber, and show that the TE01 is indeed the lowest loss mode, and is less lossy and has a much wider band gap than the HE11. We study the superpostions of the HE11 and TE01 modes using the pure phase approach, and discuss the degeneracy problem that arises. We analyze these superpositions by decomposing the superposed images into low energy eigenmodes (m < 3), and compute each of the eigenmode's contribution in the superposition. We show that the contributions of the HE11 and TE01 behave sinusoidally in their superpostions. Finally we also explain the minor discrepancies between the superposition and decomposition results.
y Qichao Hu.
S.B.
19
Tang, Xiaofeng. "The fabrication of 3-D photonic band gap structures". Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/43305.
Resumen
Thesis (Elec. E.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.Includes bibliographical references (leaves 85-88).
by Xiaofeng Tang.
Elec.E.
20
Maspero, Ross. "Unfolding the band structure of electronic and photonic materials". Thesis, University of Surrey, 2017. http://epubs.surrey.ac.uk/813175/.
Resumen
In this thesis, we develop a generalised unfolding formalism to investigate the electronic and photonic properties of aperiodically-structured materials. We initially focus on GaAsBi alloys for electronic systems and Penrose-structured materials for photonic systems, aperiodic materials that cannot be easily studied using conventional band structure methods. We then extend our study to the supercell approach which facilitates an accurate modelling of the aperiodic structures at the price of obscuring essential physical information, due to a band folding effect. Then introducing a generalised unfolding algorithm, we return the supercell band structure to a traditional form that can again be used to analyse the electronic and photonic properties of the system. GaAsBi, which is a material with the potential to suppress the dominant loss mechanisms in telecommunications devices, was studied using the unfolded supercell band structure approach. We investigated the effect of bismuth on the properties of a host GaAs structure, including band movement, band broadening and effective mass. We validated our approach through a detailed comparison of both band movement and effective masses to the currently available experimental data. Then, we introduced a formalism for calculating the CHSH Auger recombination rates from our unfolded band structure, which will assist in determining the efficiency of the material. Quasicrystalline photonic materials built on the skeleton of Penrose lattices have proven to display photonic properties comparable to the ones found in photonic crystals, but with the added promise of increased isotropy. The photonic band structure of these materials is a prime target for the unfolding formalism because it allows a full exploration of the influence of the increased geometrical symmetry on their photonic characteristics. Furthermore, the network structure investigated demonstrated the existence of a sub-fundamental photonic band gap, a characteristic unique to quasicrystalline structures. The unfolded band structure enabled the investigation of the mechanisms responsible for the formation of this peculiar band gap. Finally, we depart from the frequency domain approach and employ time domain simulations to investigate the photonic and plasmonic properties of a hybrid structure consisting of a polymer based opal with a quasi-2D gold nanoparticle grid on the surface. The optical response of the structure displays an intricate interplay between the plasmonic resonances and the photonic stop band effects. Adopting a renormalised Maxwell-Garnett effective index for describing the gold nanogrid, we successfully elucidate the main physical mechanisms governing the optical response of these structures in good agreement with the results of experimental investigations.
21
Luan, Feng. "Linear and nonlinear properties of photonic band-gap fibres". Thesis, University of Bath, 2005. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.410923.
22
McLaren-Jones, Jennifer Sian Elizabeth. "Band edge lasing in chiral nematic liquid crystals". Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/288382.
Resumen
For the last 20 years, there has been considerable interest in chiral nematic liquid crystal band edge lasers. The birefringent molecules of chiral nematic liquid crystals form a periodic helical structure, which results in a photonic bandgap for circularly polarised light with the same sense of rotation as the helix. A large increase in effective gain is seen for a fluorescent gain medium within the liquid crystal at the band edges, resulting in lasing. Applications of liquid crystal lasers could include miniature medical diagnostic tools, large-area holographic laser displays, and environmental sensing. The wavelength of emission from dye-doped chiral nematic liquid crystals is highly flexible, with lasers demonstrated across the visible range and near infra-red. This thesis investigates two routes for improving the functionality of chiral nematic liquid crystal lasers, supported by mathematical modelling of expected lasing wavelengths based on reflection and transmission by anisotropic layers. Perovskite is tested as a replacement for fluorescent laser dyes as a gain medium,both in the form of quantum dots dispersed in liquid crystal, and as films placed in liquid crystal structures. It is shown that while the perovskite tested provides some emission, it is not compatible for lasing in these devices, and suggestions for building on these results are made. In-plane switching is tested and developed as a means to achieve tuning of the laser wavelength, demonstrating a continuous wavelength shift of 15 nm, from 600.71 nm to 585.03 nm, over a voltage range of 100 V. This is an improvement on previous tuning in related devices, and may be extended with optimisation of cell thickness,electrode geometry, and initial lasing wavelength. Accurate descriptions of the refractive index profile of the liquid crystal and perovskite are developed and included in mathematical modelling, in addition to descriptions of the wavelength-dependent gain of a laser dye and perovskite. Suggestions for developing this modelling are made, particularly by the inclusion of accurate modelling of the distortion caused by in-plane switching.
23
Gao, Jian. "Fluorescence Enhancement using One-dimensional Photonic Band Gap Multilayer Structure". University of Dayton / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1343753064.
24
Hung, Jenny. "3D spherical layer photonic band-gap structures in dichromate gelatin /". View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?PHYS%202008%20HUNG.
25
Charlton, Martin David Brian. "Computational design and microfabrication of photonic crystals". Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287304.
26
Watson, Ian Andrew. "Improved schemes for calculating photonic band structures and their applications". Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.394046.
27
Choi, S. S. "Electrically tuneable photonic band gaps in chiral nematic liquid crystals". Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.597631.
Resumen
This thesis investigates methods of electrically tuning the photonic band gap (PBG) in chiral nematic liquid crystals (N*LC). The electrical control of the PBG is highly desirable for practical applications, however, hitherto wavelength tuning has been limited due to the destruction of the photonic band structure (PBS) by the presence of electrically-induced out-of-plane switching and electro-hydro-dynamic instabilities. Primarily, this thesis aims to find methods for stable tuning over a broadband wavelength range with a short response time upon the application of an electric field. Using electrically commanded surface switching, a stable blue-shift of the wavelength of the band-gap up to ~23 nm is demonstrated for a N*LC with no change in the quality of the PBG. This is achieved using ferroelectric liquid crystal (FLC) surface layers which rotate in the plane of the device during the application of an electric field which results in a macroscopic contraction of the helix of the N*LC. The tuning range is found to increase considerably (> 100 nm) by doping the FLC compound into the bulk of the N*LC as electrically active dopants. In addition, by dispersing the FLC into the bulk it is shown that, under certain conditions, multiple band-gaps are observed. To improve the response time of the switching of the PBG, a hybrid PBS is investigated using a polymer template and an achiral liquid crystal. Due to the absence of electrical instabilities by using an achiral LC in a rigid periodic polymer template, a faster response (~43 μs) with a broad photonic band width (Δλ ~135 nm) and a broadband PBG shift (over 100 nm) is demonstrated. Furthermore, a PBS structure, which simultaneously reflects red-green-blue light, is fabricated using a single achiral LC.
28
Salt, Martin Guy. "Photonic band gaps in waveguide modes of textured, metallic microcavities". Thesis, University of Exeter, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302568.
29
Arsenyev, Sergey A. "Photonic band gap structures for superconducting radio-frequency particle accelerators". Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/107281.
Resumen
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2016.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 175-181).
This thesis presents the design and testing of the first multi-cell superconducting accelerating cavity with a photonic band gap (PBG) coupler cell. The structure serves as a building block for superconducting radio-frequency (SRF) electron accelerators. It has five accelerating cells: four cells of elliptical shape, commonly used for SRF cavities, and one PBG cell in the middle. The purpose of the PBG cell is to damp unwanted Higher-Order electromagnetic Modes (HOMs) in the structure. Strong HOM damping is highly desirable for SRF cavities because it increases maximum achievable beam current by reducing the negative effect that HOMs have on the propagating electron beam. In the presented structure, effective HOM damping is achieved because of the inherent frequency selective properties of the PBG cell. The HOM spectrum in the five-cell cavity was carefully analyzed using eigenmode and wakefield simulations with good agreement between the two methods. The simulations showed that most of the dangerous HOMs were damped to fairly low external quality factors on the order of 102-104. This in principle implies that the new multicell cavity will support much higher beam currents than achievable in conventional SRF cavities that are not optimized for high-current operation. The improved HOM damping does not significantly compromise the accelerating properties of the cavity which are comparable to those of the cavities that only use the elliptical cells. Additionally, the PBG cavity does not need HOM couplers on the beam-pipe sections of the structure, and hence for the same amount of acceleration has a shorter length in the direction of the propagating beam. The five-cell cavity was fabricated of high purity niobium. Fabrication and tuning mechanisms were successfully tested on a copper prototype before being implemented for the niobium cavity. The accelerating gradient profile in the tuned niobium cavity matched the desired profile within a 5% accuracy. Two cryogenic tests were conducted with the five-cell cavity. The first test did not succeed due to a problem with the low quality factor of the cavity's accelerating mode. The problem was identified as a poor waveguide joint in the fundamental power coupler. Modifications were made to the waveguide joint and a second cryogenic test was conducted. In the second test, the high cavity quality factor was demonstrated at the temperature of 4.2 K for accelerating gradients up to 3 MV/m. The measured value of the cavity's quality factor with all ports closed was 1.55 x 108, in agreement with the prediction. This agreement indicated that the implemented surface treatment was effective in the cavity, including the complex PBG cell. No cavity leaks were observed during the tests in superfluid helium, proving the reliability of the fabrication process which included difficult electron-beam welds. No hard barriers in the accelerating gradient were observed during the test, indicating the absence of fundamental limits to cavity's operation for the gradient of at least several MV/m. A series of room-temperature experiments were conducted to measure external quality factors of six dangerous HOMs in the fabricated five-cell cavity. The measurements agreed with the simulations, showing all of the measured Q-factors below 3 x 103. Effective HOM damping, together with the ability to support accelerating gradients of multiple MV/m at cryogenic temperatures, makes the cavity an attractive candidate for future high-current accelerators.
by Sergey A. Arsenyev.
Ph. D.
30
Allahverdyan, Karen. "Study of resonant reflection in helicoidal photonic band gap structures". Doctoral thesis, Université Laval, 2015. http://hdl.handle.net/20.500.11794/25827.
Resumen
La présente thèse de doctorat rapporte une étude expérimentale sur la réflexion résonante de la lumière dans des structures hélicoïdales à bande photonique interdite. Plusieurs aspects optiques et électro-optiques des cristaux liquides cholestériques sont abordés en concentrant l’attention sur deux effets principaux: l’influence des conditions aux limites (mécaniques et optiques) sur les propriétés optiques des couches de cristaux liquides cholestériques et le contrôle de la bande interdite de ces dernières. On présente un élément à double-rétroaction optique basé sur une cavité de Fabry-Pérot remplie de cristal liquide cholestérique. Les propriétés spectrales et de polarisation de cet élément sont caractérisées expérimentalement et par des simulations théoriques. Un changement mineur dans la structure en haut (cavité de Fabry-Pérot) nous a permis d’obtenir une transmission non-réciproque de la lumière sans application d’un champ externe à l’élément en question. Nous avons observé une transmission non-réciproque de la lumière par un système qui ressemble beaucoup aux structures naturelles observées sur certaines carapaces d’insectes (par exemple, sur les élytres de certains coléoptères): une simple couche de matière transparente linéaire dans son état fondamental. L’effet est défini par deux facteurs principaux: la chiralité et la périodicité de la matière ainsi que les conditions asymétriques aux surfaces limites. Concernant la partie sur le contrôle de la bande interdite, nous présentons la création et l’utilisation du mélange de cristal liquide cholestérique à deux fréquences pour le ‘déroulement’ et la reconstruction dynamique de la structure hélicoïdale. Le processus de reconstruction est accéléré d’un ordre de grandeur par l’application de champs électriques modérés. L’étape suivante du contrôle de la bande interdite est l’accord en longueur d’onde de la bande interdite. Un effet électromécanique est utilisé pour générer et étudier l’auto-adaptation du pas d’hélice de la couche de cristal liquide cholestérique. L’anisotropie négative diélectrique a permis d’assurer la stabilisation de la structure hélicoïdale de la couche pendant l’application du champ électrique qui a aussi changé l’épaisseur de la couche de cristal liquide en pliant un des substrats minces de la cellule. Cette déformation de la couche a généré un d’accord (et des sauts) des longueurs d’onde de la bande interdite. Les études spectrales et morphologiques pendant les changements de la bande interdite sont présentées et discutées.The present PhD thesis reports experimental study of resonant reflection in helicodal photonic band gap structures. Several optical and electro-optical properties of cholesteric liquid crystals are investigated where attention was concentrated on two principal phenomena: the influence of mechanical and optical boundary conditions on optical properties of cholesteric liquid crystal layers and control of photonic band gap of cholesteric liquid crystals. The creation of a double-feedback optical element based on a Fabry-Perot cavity filled with a planar aligned cholesteric liquid crystal mixture is presented. The polarization and spectral properties of this element are characterized experimentally and simulated theoretically. Experimental results are obtained for the transmittance dependence upon the orientation of the linear polarization plane and the polarization state of incident probe beam. A slight change in above mentioned structure (Fabry-Perot cavity) let us obtain a non-reciprocal transmittance of light without applying any external field. We observed an optical non reciprocity in a material system that is very close to natural structures, such as insect skin: a single layer of linear transparent material in its ground state. The process is shown to be defined by two key parameters: the chiral and periodic nature of the material and its asymmetric boundary conditions. In the part of band gap control, we present the creation and the use of dual frequency cholesteric liquid crystal mixtures for the dynamic electrical unwinding and forced (accelerated) restoring of their molecular helix. The restoring process is accelerated almost by an order of magnitude for quite moderate voltages used. The next step of band gap control is the tuning of band gap (wavelength). Strong electromechanical effect was used to generate and study self-adaptation and pitch jumps in a layer of cholesteric liquid crystal. The negative dielectric anisotropy of the material allowed its stabilization by the electric field and important thickness changes, achieved thanks to the use of a very thin substrate, allowed the observation of multiple dynamic jumps at fixed deformation conditions. Spectral and morphological studies of the material during those jumps were performed and are presented.
31
Jiang, Rui. "Parametric band translation using highly-nonlinear and photonic crystal fibers". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2008. http://wwwlib.umi.com/cr/ucsd/fullcit?p3330316.
Resumen
Thesis (Ph. D.)--University of California, San Diego, 2008.Title from first page of PDF file (viewed November 17, 2008). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 234-247).
32
Kwan, Kai-Cheong. "The effects due to disorder in the applications of photonic band gap materials /". View Abstract or Full-Text, 2002. http://library.ust.hk/cgi/db/thesis.pl?PHYS%202002%20KWAN.
Resumen
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2002.Includes bibliographical references (leaves 58-59). Also available in electronic version. Access restricted to campus users.
33
Kurt, Hamza. "Photonic crystals analysis, design and biochemical sensing applications /". Diss., Available online, Georgia Institute of Technology, 2006, 2006. http://etd.gatech.edu/theses/available/etd-06252006-174301/.
Resumen
Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2007.Papapolymerou, John, Committee Member ; Adibi, Ali, Committee Member ; Citrin, David, Committee Chair ; Summers, Christopher, Committee Member ; Voss, Paul, Committee Member.
34
Wu, Jay-Hsing 1979. "Characterization of planar photonic band gap structures with controllable bandstop widths". Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80153.
Resumen
The effects of planar PBG structure with microstrip transmission line were investigated. Both measurement and simulation results are compared and the bandstop characteristics such as 3 dB bandstop width, central bandstop frequency, and maximum attenuation were examined. Also, various dimensions of PBG structure were explored to demonstrate the correlation to the bandstop effects. It was found that the central bandstop frequency is directly depended on the period distance (a). Meanwhile, the maximum attenuation was observed to depend on the number of periods presented in the ground plane. Furthermore, the vertical scale of the square perforation to the period distance ratio (d/a) was found to affect the left bandstop edge consistently. As the ratio is increased from 0.2 to 0.9, the left bandstop edge shifts toward the lower frequencies steadily and the range of the frequency shift is around 3.5 GHz. This important finding gives the PBG structure the potential to be tuned.Moreover, the possibilities of switching and tuning of the PBG structure were also investigated. Switching of the PBG structure with a gold metal piece electrically was successfully demonstrated. At 16 GHz, the bandstop effect is being switched off from -35 dB to -1 dB. Also, tuning of the bandstop edge was demonstrated and the range of frequency shift measured is 1.5 GHz. Therefore, the switching and tuning abilities of the PBG structure can be utilized as tunable filters.
35
Benoit, Gilles Ph D. Massachusetts Institute of Technology. "Tunable micro-cavities in photonic band-gap yarns and optical fibers". Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/36206.
Resumen
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2006.Includes bibliographical references (leaves 134-140).
The vision behind this work is the fabrication of high performance innovative fiber-based optical components over kilometer length-scales. The optical properties of these fibers derive from their multilayer dielectric photonic band-gap structure that exhibits omnidirectional reflectivity. The theoretical tools needed to design, analyze and optimize such structures are introduced. We show that defect layers in these otherwise periodic structures act as optical micro-cavities that enable precise design of the fibers' spectral response. Fabrication of these composite fibers by thermal drawing of a macroscopic preform in the viscous state requires solving material selection challenges in order to identify pairs of materials with high refractive index contrast and similar thermo-mechanical properties. Operational wavelengths ranging from the UV to the IR are demonstrated and made possible by the wavelength scalability of the photonic band-gap structure and accurate knowledge of the materials' dispersion relation afforded by broadband spectroscopic ellipsometry. The fundamentals of this technique, which is used to characterize a number of dielectrics, semi-conductors and metals, are surveyed. Two fiber structures are then explored: fibers for external reflection and hollow-core transmission fibers.
(cont.) We demonstrate that the resonance wavelength of Fabry-Perot cavities embedded in reflecting fibers can be tuned reversibly under applied elastic strain or external illumination at 514 nm. A simple opto-mechanical model is developed to assess the mechanical tuning efficiency while a review of the photodarkening effect in chalcogenide glasses and accurate measurements of the amplitude and response time associated with its transient component are presented to explain and optimize the optical tuning scheme. Modulation of the fibers' reflectivity near their cavity resonant wavelengths is demonstrated at various frequencies. Based on these results, we show that optical micro-cavities in transmission fibers can induce very high group-velocity dispersion as a result of the interaction between the propagating core modes and the lossy cavity resonant mode(s). Widely tunable dispersion is achieved using a mechanical tuning scheme. Applications for these fibers and future research directions are envisioned.
by Giles Benoit.
Ph.D.
36
Amoah, T. K. "Designer disordered complex media : hyperuniform photonic and phononic band gap materials". Thesis, University of Surrey, 2016. http://epubs.surrey.ac.uk/812500/.
Resumen
In this thesis we investigate designer disordered complex media for photonics and phononics applications. Initially we focus on the photonic properties and we analyse hyperuniform disordered structures (HUDS) using numerical simulations. Photonic HUDS are a new class of photonic solids, which display large, isotropic photonic band gaps (PBG) comparable in size to the ones found in photonic crystals (PC). We review their complex interference properties, including the origin of PBGs and potential applications. HUDS combine advantages of both isotropy due to disorder (absence of long-range order) and controlled scattering properties from uniform local topology due to hyperuniformity (constrained disorder). The existence of large band gaps in HUDS contradicts the long-standing intuition that Bragg scattering and long-range translational order is required in PBG formation, and demonstrates that interactions between Mie-like local resonances and multiple scattering can induce on their own PBGs. The discussion is extended to finite height effects of planar architectures such as pseudo-band-gaps in photonic slabs as well as the vertical confinement in the presence of disorder. The particular case of a silicon-on-insulator compatible hyperuniform disordered network structure is considered for TE polarised light. We address technologically realisable designs of HUDS including localisation of light in point-defect-like optical cavities and the guiding of light in free-form PC waveguide analogues. Using finite-difference time domain and band structure computer simulations, we show that it is possible to construct optical cavities in planar hyperuniform disordered solids with isotropic band gaps that efficiently confine TE polarised radiation. We thus demonstrate that HUDS are a promising general-purpose design platform for integrated optical micro-circuitry. After analysing HUDS for photonic applications we investigate them in the context of elastic waves towards phononics applications. We demonstrate the first phononic band gaps (PnBG) for HUDS. We find that PnBGs in phononic HUDS can confine and guide elastic waves similar to photonic HUDS for EM radiation.
37
Yarga, Salih. "REALIZATIONS OF DEGENERATE BAND EDGE/MAGNETIC PHOTONIC CRYSTALS FOR ANTENNA APPLICATIONS". The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1253641248.
38
VALLONE, MARCO ERNESTO. "Physics-based simulation of narrow and wide band gap photonic devices". Doctoral thesis, Politecnico di Torino, 2016. http://hdl.handle.net/11583/2639782.
Resumen
Historically, infrared (IR) detector technologies are connected mainly with controlling and night-vision problems: in a first stage, applications concerned simply with detection of IR radiation, but very soon capabilities to form IR images were developed, opening the way to systems for recognition and surveillance, especially for military purposes. Since the last decade of the twentieth century, the use of IR imaging systems for civil and peaceful purposes have increased continuously: these include medical and industrial applications, detection of earth resources, earth and universe sciences, etc. As an example, IR imaging is widely used in astronomy, to study interstellar medium and first-stages of stellar evolution; in medicine, IR thermography – IR imaging of the human body – is employed to detect cancers or other trauma; IR detectors are also widely used in automotive industry, chemical process monitoring, global monitoring of environmental pollution and climate changes, etc. The discovery in 1959 by Lawson and co-workers of the wide tunability of the HgCdTe alloy allowed this compound to become one of the most important and versatile materials for detector applications over the entire IR range. A critical contribution to research is given by Technology Computer-Aided Design (TCAD), modeling and simulation. In the first part of this thesis, I present the main part of my research activity, focused on the development of abilities and methodologies for the simulation of realistic three-dimensional HgCdTe-based infrared photodetectors. The purpose is the investigation of generation-recombination (GR) mechanisms and modeling of spectral photoresponse in narrow-gap HgCdTe-based photodetectors, with one-, two and three-dimensional (1D, 2D, 3D) realistic TCAD models (Chapters 1-5).
Another important topic of industrial research in semiconductor physics deals with nitride-based light-emitting diodes (LEDs). From automotive to streetlights, from lights in our houses to the displays of TVs and smartphones, LED-based technology is making its way in the market. This proliferation would have been impossible without GaN-based LEDs, whose invention by Isamu Akasaki, Hiroshi Amano and Shuji Nakamura has been rewarded with the 2014 Nobel Prize in Physics. Nevertheless, GaN-based LEDs performanceis limited by a reduction (droop) of their internal quantum efficiency (IQE) as the driving current density is increased beyond 10 A/cm2, whose physical origin is still under intense debate. In the second part of this thesis, I present a quantum model, based on condensed matter many-body theory, that allowed to obtain the electron capture time and hot-electron intraband relaxation times in a quantum well (QW)-barrier heterostructure, for longitudinal optic (LO) phonon emission, as function of carrier density. The interaction was described in the Single Plasmon Pole of the Random Phase Approximation, retaining the full density-, energy- and wavevector-dependent form of the dielectric function (Chapters 6-7).
39
Singh, Akhilesh K. "Broad-band Light Emission From Ion Implanted Silicon Nanocrystals Via Plasmonic and Non-plasmonic Effects for Optoelectronics". Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc177255/.
Resumen
Broad band light emission ranging from the ultraviolet (UV) to the near infrared (NIR) has been observed from silicon nanoparticles fabricated using low energy (30-45 keV) metal and non-metal ion implantation with a fluence of 5*1015 ions/cm2 in crystalline Si(100). It is found from a systematic study of the annealing carried out at certain temperatures that the spectral characteristics remains unchanged except for the enhancement of light emission intensity due to annealing. The annealing results in nucleation of metal nanoclusters in the vicinity of Si nanoparticles which enhances the emission intensity. Structural and optical characterization demonstrate that the emission originates from both highly localized defect bound excitons at the Si/Sio2 interface, as well as surface and interface traps associated with the increased surface area of the Si nanocrystals. The emission in the UV is due to interband transitions from localized excitonic states at the interface of Si/SiO2 or from the surface of Si nanocrystals. The radiative efficiency of the UV emission from the Si nanoparticles can be modified by the localized surface plasmon (LSP) interaction induced by the nucleation of silver nanoparticles with controlled annealing of the samples. The UV emission from Si nanoclusters are coupled resonantly to the LSP modes. The non-resonant emission can be enhanced by electrostatic-image charge effects. The emission in the UV (~3.3 eV) region can also be significantly enhanced by electrostatic image charge effects induced by Au nanoparticles. The UV emission from Si nanoclusters, in this case, can be coupled without LSP resonance. The recombination of carriers in Si bound excitons is mediated by transverse optical phonons due to the polarization of the surface bound exciton complex. The low energy side of emission spectrum at low temperature is dominated by 1st and 2nd order phonon replicas. Broad band emission ranging from the UV to the NIR wavelength range can be obtained from Ag implanted onto a single silicon substrate.
40
Neff, Curtis Wayne. "Optical Properties of Superlattice Photonic Crystals". Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/14108.
Resumen
Photonic band gap materials, commonly referred to as photonic crystals (PCs), have been a topic of great interest for almost two decades due to their promise of unprecedented control over the propagation and generation of light. We report investigations of the optical properties of a new PC structure based upon a triangular lattice in which adjacent [i, j] rows of holes possess different properties, creating a superlattice (SL) periodicity. Symmetry arguments predicted and quot;band folding and quot; and band splitting behaviors, both of which are direct consequences of the new basis that converts the Brillouin zone from hexagonal (six-fold) to rectangular (two-fold). Plane wave expansion and finite-difference time-domain (FDTD) numerical calculations were used to explore the effects of the new structure on the photonic dispersion relationship of the SL PC. Electron beam lithography and inductively coupled plasma dry etching were used to fabricate 1 mm2 PC areas (lattice constant, a =358 nm and 480 nm) with hole radius ratios ranging from 1.0 (triangular) to 0.585 (r2/r1 = 73.26 nm/125.26 nm) on Silicon-on-insulator wafers. The effects of modifying structural parameters (such as hole size, lattice constant, and SL strength) were measured using the coupled resonant band technique, confirming the SL symmetry arguments and corroborating the band structure calculations. Analysis of the dispersion contours of the static SL (SSL) PC predicted both giant refraction (change in beam propagation angle of 110 for an 8 change in incident angle) and superprism behavior (change in beam propagation angle of 108 for a 12% change in normalized frequency) in these structures. Dynamic control of these refraction effects was also investigated by incorporating electro-optic and nonlinear materials into the SSL PC structure. Wave vector analyses on these structures predicted a change in beam propagation angle and gt;96 when the refractive index inside of the holes of the structure changed from n=1.5 to 1.7. Through this investigation, the first successful measurement of the band folding effect in multidimensional PCs as well as the first explicit measurement of the dielectric band of a 2D PC were reported. In addition, the SL PCs impact on new opto-electronic devices was explored.
41
Smith, Christopher J. M. "Waveguide photonic microstructures in III-V semiconductors". Thesis, University of Glasgow, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300978.
42
CHINCHOLI, ASHWIN. "PARALLEL FABRICATION OF PHOTONIC CRYSTALS USING INTERFERENCE LITHOGRAPHY". University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1115996014.
43
Reynolds, Andrew Lawrence. "Modelling of photonic band gap materials for mm-wave and optical applications". Thesis, University of Glasgow, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325302.
44
Hughes, Alison Frances. "A new theory of lasers with application to photonic band gap materials". Thesis, King's College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368127.
45
Aldukhayel, Abdullah Mohammed. "Physical process in inter-band and inter-subband mid-infrared photonic devices". Thesis, University of Surrey, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.658624.
Resumen
Mid-infrared light emitting diodes and quantum cascade lasers are of increasing interest due to their promising applications. They can be used in detecting and monitoring pollutant gases such as methane (CH4) and carbon dioxide (C02), Such devices are preferred for these purposes due to their potential for high sensitivity for detecting gases, long device lifetime, and potential low-cost. Mid-infrared light emitting diodes emitting at a wavelength of 3.7 !-lm based on the pentanary alloy GaInAsSbP engineered to provide a favourable band structure for the suppression of non-radiative Auger recombination were investigated. Temperature dependence measurements were made to investigate the performance of these LEDs. Hydrostatic pressure measurements at room temperature and at 100 K were used to tune the band gap towards resonance with the spin-orbit splitting to inv,estigate the influence of the hot-hole (CHSH) Auger process on LED performance. Analysis of the resulting electroluminescence showed that while Auger recombination related to hot electrons occurs, it confirms that the nonradiative Auger recombination process involving the spin-orbit split-off band (CHSH) is suppressed under ambient conditions. In order to identify the performance limitations of InGaAsI AIAs(Sb) quantum cascade lasers, experimental investigations of the temperature and pressure dependenGies of the threshold current (Ith) were undertaken. Using the theoretically estimated optical phonon current (Iph) and calculated carrier leakage (I leak) as a function of pressure the measured pressure dependence of the threshold current showed that electron scattering from the upper laser level into the L valley minima gives rise to the increase in Ith with pressure and temperature. It was found that this carrier leakage path accounts for approximately 3 % of Ith at R T and is negligible at 100 K. However, it is shown that even this small leakage current causes strong temperature sensitivity of the devices and limits their maximum operating temperature.
46
Hao, Ran. "Wide-band low-dispersion low-losses slow light in photonic crystal waveguides". Paris 11, 2010. http://www.theses.fr/2010PA112351.
Resumen
Cette thèse apporte des contributions à la résolution de problèmes actuels concernant les effets de lumière lente dans des guides d'ondes à cristaux photoniques dans le but d'obtenir une large bande passante, une faible dispersion, et de faibles pertes de propagation. De nouveaux types de guides à cristaux photoniques sont proposés ayant une large bande passante, une faible dispersion de vitesse de groupe, et permettant un contrôle flexible des propriétés d’ondes lentes avec des exigences raisonnables en terme de fabrication des structures par les technologies de salle blanche. Une approche globale visant à améliorer le produit délai×bande passante des dispositifs présents est proposée. En utilisant cette approche, le produit normalisé délai×bande passante a été amélioré d’un facteur 15 par rapport à l’état de l’art des guides conçus pour fonctionner avec un indice de groupe moyen de 90. Les pertes induites par la fabrication ont également été étudiées. Nous avons modélisé quatre types de désordre dans la fabrication des structures réelles. Les résultats obtenus ont permis de quantifier combien la région à proximité du centre du défaut linéique a une influence dominante sur les pertes. Enfin, tous les résultats de conception ont été utilisés pour la fabrication de plaques de silicium sur isolant préparées pour la démonstration des effets prévus de lumière lenteThis Ph. D study brings contributions of solving present problems for slow light in photonic crystal waveguides, aiming to obtain wide-band, low-dispersion, and low losses slow light. Novel kinds of photonic crystal waveguides are proposed having large bandwidth, low group velocity dispersion and allowing a flexible control of slow light properties with reasonable requirements to clean room fabrication. An overall approach to improve the delay-bandwidth product of present slow light devices is proposed. By using this approach, the normalized delay-bandwidth product of previous waveguides has been improved by a factor of 15 if compared with regular photonic crystal waveguides with a group index maintained at the high value of 90. The fabrication induced losses have also been studied. We modeled four kinds of structure disorders in real fabrication. The obtained results quantify how much the region close to the line defect center has a dominant influence on the losses. Finally, all design results have been used for the fabrication of silicon-on-insulator samples prepared for the demonstration of the foreseen slow light effects
47
Kang, Henry Hao-Chuan. "Fabrication of Ceramic Layer-by-Layer Infrared Wavelength Photonic Band Gap Crystals". Washington, D.C. : Oak Ridge, Tenn. : United States. Dept. of Energy. Office of Science ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2004. http://www.osti.gov/servlets/purl/835375-KQ7RuV/webviewable/.
48
Li, Jianyou. "Oligonucleotide guanosine conjugated to gallium nitride nano-structures for photonics". Thesis, University of North Texas, 2008. https://digital.library.unt.edu/ark:/67531/metadc9065/.
Resumen
In this work, I studied the hybrid system based on self-assembled guanosine crystal (SAGC) conjugated to wide-bandgap semiconductor gallium nitride (GaN). Guanosine is one of the four bases of DNA and has the lowest oxidation energy, which favors carrier transport. It also has large dipole moment. Guanosine molecules self-assemble to ribbon-like structure in confined space. GaN surface can have positive or negative polarity depending on whether the surface is Ga- or N-terminated. I studied SAGC in confined space between two electrodes. The current-voltage characteristics can be explained very well with the theory of metal-semiconductor-metal (MSM) structure. I-V curves also show strong rectification effect, which can be explained by the intrinsic polarization along the axis of ribbon-like structure of SAGC. GaN substrate property influences the properties of SAGC. So SAGC has semiconductor properties within the confined space up to 458nm. When the gap distance gets up to 484nm, the structure with guanosine shows resistance characteristics. The photocurrent measurements show that the bandgap of SAGC is about 3.3-3.4eV and affected by substrate properties. The MSM structure based on SAGC can be used as photodetector in UV region. Then I show that the periodic structure based on GaN and SAGC can have photonic bandgaps. The bandgap size and the band edges can be tuned by tuning lattice parameters. Light propagation and emission can be tuned by photonic crystals. So the hybrid photonic crystal can be potentially used to detect guanosine molecules. If guanosine molecules are used as functional linker to other biomolecules which usually absorb or emit light in blue to UV region, the hybrid photonic crystal can also be used to tune the coupling of light source to guanosine molecules, then to other biomolecules.
49
Fang, Wie-hua y 方偉華. "Study of photonic xrystal band structure". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/34909589593901915404.
Resumen
碩士國立中正大學
物理所
94
In the nearly 20 years, the photon crystal research is continuously noticeable in each domain application, In this paper, we use the plane wave method to calculates several kinds in one-idimensional, two-dimensional and three-dimensional photon crystal band sturcure, and in the computation study of several kind of three-dimentional photonic crystal band structure in physics department Professor Hsu Chia chen the laboratory uses for the Multi-exposure of two-beam interference technique makes.
50
"Theory of photonic band gap materials". Chinese University of Hong Kong, 1994. http://library.cuhk.edu.hk/record=b5888205.
Resumen
Lee Wai Ming.Thesis (M.Phil.)--Chinese University of Hong Kong, 1994.
Includes bibliographical references (leaves 177-181).
List of Figures and Tables --- p.iii
Chapter 1 --- Introduction --- p.1
Chapter 1.1 --- Photonic Band Gap materials --- p.1
Chapter 1.2 --- Theoretical Calculation on PBG materials --- p.5
Chapter 2 --- Plane Wave Expansion --- p.13
Chapter 2.1 --- Plane Wave Expansion within Scalar Wave Approximation --- p.14
Chapter 2.2 --- Plane Wave Expansion to Scalar I and II Equations --- p.21
Chapter 3 --- Formalism of Photonic k.p Theory --- p.33
Chapter 3.1 --- Vectorial k.p formulation --- p.33
Chapter 3.2 --- Scalar k. p formulations --- p.36
Chapter 4 --- Implementation and k.p Band Structures --- p.38
Chapter 4.1 --- Evaluation of Integrals plj and qlj --- p.38
Chapter 4.2 --- k.p Band Models --- p.47
Chapter 5 --- Dependence of k .p Parameters on Dielectric Contrast and Fill- ing Ratio --- p.57
Chapter 5.1 --- Accuracy of Integrals plj and qlj --- p.57
Chapter 5.2 --- Sensitivity of k.p Parameters to System Parameters --- p.71
Chapter 6 --- Empirical Tight-binding Scheme --- p.99
Chapter 6.1 --- Electronic Tight Binding Approximation --- p.99
Chapter 6.2 --- Empirical Tight-binding Scheme --- p.101
Chapter 7 --- Summary --- p.137
Chapter A --- Preprint of Ref. [36] --- p.144
Chapter B --- The Coefficients in Eq. (2.22) --- p.161
Chapter C --- Formalism of Photonic k.p Theory --- p.163
Chapter D --- The Coefficients in Eq. (5.2) --- p.166
Chapter E --- The Coefficients in Eq. (5.3) --- p.168
Chapter F --- The Coefficients in Eq. (6.15) --- p.170