摘要 :
In this funding period, the P.I. investigated nonlinear light propagation in one- and two-dimensional optically-induced photonic lattices both theoretically and experimentally. Photonic lattices in these works were created by opti...
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In this funding period, the P.I. investigated nonlinear light propagation in one- and two-dimensional optically-induced photonic lattices both theoretically and experimentally. Photonic lattices in these works were created by optical induction and were highly tunable in real time, thus they provided a convenient medium to study novel physical phenomena of light propagation in periodic and quasiperiodic media. P.I. discovered many new types of nonlinear localized modes (optical solitons) in photonic lattices, such as saddle solitons, truncated-Bloch-mode solitons, two-dimensional embedded solitons, soliton trains, and arbitrary-shape solitons. The finding of these new types of optical solitons offers new possibilities for nonlinear light localization in photonic lattices. His theoretical discovery of arbitrary-shape solitons in photonic lattices also led to a novel image transmission scheme through nonlinear media, and this scheme was successfully demonstrated experimentally. He demonstrated that a nonlinear beam can be reflected by a negative (repulsive) defect in a photonic lattice if the incident angle is below a threshold value. Above this threshold angle, the beam simply passes through the defect. This phenomenon provides a way to use the incident angle to control beam propagation in a lattice network. Furthermore, a negative defect can guide various linear defect modes (such as vortex modes) without any diffraction. P.I. also developed a mathematical technique (the exponential asymptotics method) for the study of existence and linear stability of solitons in photonic lattices. P.I. invented a new numerical method--the Newton-conjugate-gradient method, which can efficiently determine solitons in photonic lattices.
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摘要 :
Photonic crystals are periodically engineered 'materials' which are the photonic analogues of electronic crystals. Much like electronic crystal, photonic crystal materials can have a variety of crystal symmetries, such as simple-c...
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Photonic crystals are periodically engineered 'materials' which are the photonic analogues of electronic crystals. Much like electronic crystal, photonic crystal materials can have a variety of crystal symmetries, such as simple-cubic, closed-packed, Wurtzite and diamond-like crystals. These structures were first proposed in late 1980's. However, due mainly to fabrication difficulties, working photonic crystals in the near-infrared and visible wavelengths are only just emerging. In this article, we review the construction of two- and three dimensional photonic crystals of different symmetries at infrared and optical wavelengths using advanced semiconductor processing. We further demonstrate that this process lends itself to the creation of line defects (linear waveguides) and point defects (micro-cavities), which are the most basic building blocks for optical signal processing, filtering and routing.
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The fundamental spontaneous emission rate for a photon source can be modified by placing the emitter inside a periodic dielectric structure allowing the emission to be dramatically enhanced or suppressed depending on the intended ...
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The fundamental spontaneous emission rate for a photon source can be modified by placing the emitter inside a periodic dielectric structure allowing the emission to be dramatically enhanced or suppressed depending on the intended application. We have investigated the relatively unexplored realm of interaction between semiconductor emitters and three dimensional photonic crystals in the visible spectrum. Although this interaction has been investigated at longer wavelengths, very little work has been done in the visible spectrum. During the course of this LDRD, we have fabricated TiO(sub 2) logpile photonic crystal structures with the shortest wavelength band gap ever demonstrated. A variety of different emitters with emission between 365 nm and 700 nm were incorporated into photonic crystal structures. Time-integrated and time-resolved photoluminescence measurements were performed to measure changes to the spontaneous emission rate. Both enhanced and suppressed emission were demonstrated and attributed to changes to the photonic density of states.
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摘要 :
Localization of light to less than a cubic wavelength, (lambda)(sup 3), has important quantum consequences. The creation of single mode cavities and the modification of spontaneous emission are two important examples. A defect for...
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Localization of light to less than a cubic wavelength, (lambda)(sup 3), has important quantum consequences. The creation of single mode cavities and the modification of spontaneous emission are two important examples. A defect formed inside a three-dimensional (3D) photonic crystal provides an unique optical environment for light localization. Single mode defect cavities were built, for the first time, from an infrared 3D photonic crystal. A cavity state with modal volume of less than one (lambda)(sup 3) was observed.
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Theoretical and experimental analysis of active, absorption induced optical tuning of silicon photonic devices using silicon strip waveguides combined with nematic liquid crystal (NLC) claddings. Tuning of the silicon structures i...
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Theoretical and experimental analysis of active, absorption induced optical tuning of silicon photonic devices using silicon strip waveguides combined with nematic liquid crystal (NLC) claddings. Tuning of the silicon structures is performed under low power photo irradiation, which offers a very simple way to control the spectral response of ring resonator devices.
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In this work, we report the realization of a series of silicon 3D photonic crystals operating in the infrared (IR), mid-IR and most importantly the near- IR (k= 1 -2pm) wavelengths. The structure maintains its crystal symmetry thr...
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In this work, we report the realization of a series of silicon 3D photonic crystals operating in the infrared (IR), mid-IR and most importantly the near- IR (k= 1 -2pm) wavelengths. The structure maintains its crystal symmetry throughout the entire 6-inches wafer and holds a complete photonic bandgap.
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How various deviations in perfect photonic crystals, which may arise duringfabrication, can affect the size of photonic band gaps is investigated theoretically. The emphasis is on determining the effects of misalignment of basic s...
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How various deviations in perfect photonic crystals, which may arise duringfabrication, can affect the size of photonic band gaps is investigated theoretically. The emphasis is on determining the effects of misalignment of basic structural elements and overall surface roughness, because of their general fabrication relevance. As an example, calculations on a newly proposed three dimensional photonic crystal are performed. It is shown that the size of the gap is tolerant to significant amounts of deviation from the perfect structure.
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In this report, the studying methods and the behavior of mainly straight PBG waveguides, are demonstrated. Field computation is done using FDTD. By post-processing of the obtained field-data, waveguide properties can be presented ...
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In this report, the studying methods and the behavior of mainly straight PBG waveguides, are demonstrated. Field computation is done using FDTD. By post-processing of the obtained field-data, waveguide properties can be presented in a compact and readable form. Dielectric plate waveguide theory is utilized with 2-D FDTD simulation. Like this, without 3-D FDTD, the waveguiding characteristics of a complicated 3-D structure can be approximated.
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These sessions practically covered all modern aspects of metamaterials and plasmonic materials such as: *bottom-up manufacturing methods *plasmonics structures and antennas for biomedical applications *negative group delay (NGD) c...
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These sessions practically covered all modern aspects of metamaterials and plasmonic materials such as: *bottom-up manufacturing methods *plasmonics structures and antennas for biomedical applications *negative group delay (NGD) concept and applications *
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