Showing papers on "Photonic crystal published in 1995"

Photonic Crystals: Molding the Flow of Light

Abstract: Since it was first published in 1995, Photonic Crystals has remained the definitive text for both undergraduates and researchers on photonic band-gap materials and their use in controlling the propagation of light. This newly expanded and revised edition covers the latest developments in the field, providing the most up-to-date, concise, and comprehensive book available on these novel materials and their applications. Starting from Maxwell's equations and Fourier analysis, the authors develop the theoretical tools of photonics using principles of linear algebra and symmetry, emphasizing analogies with traditional solid-state physics and quantum theory. They then investigate the unique phenomena that take place within photonic crystals at defect sites and surfaces, from one to three dimensions. This new edition includes entirely new chapters describing important hybrid structures that use band gaps or periodicity only in some directions: periodic waveguides, photonic-crystal slabs, and photonic-crystal fibers. The authors demonstrate how the capabilities of photonic crystals to localize light can be put to work in devices such as filters and splitters. A new appendix provides an overview of computational methods for electromagnetism. Existing chapters have been considerably updated and expanded to include many new three-dimensional photonic crystals, an extensive tutorial on device design using temporal coupled-mode theory, discussions of diffraction and refraction at crystal interfaces, and more. Richly illustrated and accessibly written, Photonic Crystals is an indispensable resource for students and researchers.Extensively revised and expanded Features improved graphics throughout Includes new chapters on photonic-crystal fibers and combined index-and band-gap-guiding Provides an introduction to coupled-mode theory as a powerful tool for device design Covers many new topics, including omnidirectional reflection, anomalous refraction and diffraction, computational photonics, and much more.

Metallic photonic band-gap materials

Abstract: We calculate the transmission and absorption of electromagnetic waves propagating in two-dimensional (2D) and 3D periodic metallic photonic band-gap (PBG) structures. For 2D systems, there is substantial difference between the {ital s}- and {ital p}-polarized waves. The {ital p}-polarized waves exhibit behavior similar to the dielectric PBG`s. But, the {ital s}-polarized waves have a cutoff frequency below which there are no propagating modes. For 3D systems, the results are qualitatively the same for both polarizations but there are important differences related to the topology of the structure. For 3D structures with isolated metallic scatterers (cermet topology), the behavior is similar to that of the dielectric PBG`s, while for 3D structures with the metal forming a continuous network (network topology), there is a cutoff frequency below which there are no propagating modes. The systems with the network topology may have some interesting applications for frequencies less than about 1 THz where the absorption can be neglected. We also study the role of the defects in the metallic structures.

Localization of Superradiance near a Photonic Band Gap.

Abstract: We describe collective spontaneous emission of $N$ two-level atoms placed within a photonic band-gap material. When the atomic resonance frequency lies at the band edge, superradiant emission remains localized in the vicinity of the atoms. This leads to a steady state with spontaneously broken symmetry in which the atomic system acquires a macroscopic polarization. The superradiant decay rate is proportional to ${N}^{2/3}$ and ${N}^{2}$ for isotropic and anisotropic 3D band gaps, respectively. The corresponding peak intensity of superradiance is proportional to ${N}^{5/3}$ and ${N}^{3}$, respectively.

Optical spectroscopy of opal matrices with CdS embedded in its pores: Quantum confinement and photonic band gap effects

Abstract: The spectra of transmission and reflection of synthetic opal which has 3-dimensional periodic structure were measured at different orientations of incident beam relative to the sample facets. It is shown that opal behaves as «semi-metallic» photonic band gap (PBG) material in the vicinity of photon energy 2.3 eV. The synthesis of CdS microcrystals embedded in the pores of opal was made for the first time in an attempt to form a system of quantum dots. Optical spectra (reflection and transmission, photoluminescence and Raman scattering) were studied. The results demonstrate good crystallinity of microcrystals embedded in opal matrix and exhibit well-pronounced quantum confinement effects in fundamental edge absorption spectra. The spectral overlap of the PBG of opal with electronic band gap of many of II–VI semiconductors seems to make opal/semiconductor system a promising media for experimental studies of such PBG-related effects as inhibition of spontaneous emission, microcavity polariton, etc.

Confined electrons and photons : new physics and applications

Abstract: Confined Electrons and Photons: A Summary:.- Basic Solid State Optics in Bulk and 2D Structures.- Dynamics of Optical Excitations in Semiconductors.- Optical Transitions, Excitons and Polaritons in Bulk and Low-Dimensional Semiconductor Structures.- Electron States in Biased Heterostructures.- Phonons and Electron-Phonon Interaction in Low-Dimensional Structures.- Excitonic Radiative Dynamics in Semiconductor Quantum Wells.- Superlattices and Quantum Wells in Organic Semiconductors: Excitons and Optical Non-linearities.- Intersubband Transitions in Quantum Wells.- Confined Electrons in 1D and 0D.- Principles of Electron Solid State Electron Optics.- Atomic-like Spectroscopy of Low Dimensional Electron Systems.- Inelastic Scattering and Thermalization in low-III-V Semiconductor Structures.- Synthesis and Spectroscopy of II-VI Quantum Dots: an Overview.- Prospects of High Efficiency Quantum Boxes obtained by direct epitaxial growth.- Confined Photons.- Atoms in Cavities.- Controlling Spontaneous Emission and Optical Microcavities.- Spontaneous Emission Control in Semiconductor Microcavities.- Strong Coupling in Semiconductor Microcavities.- Localization of Light in Disordered and Periodic Dielectrics.- Photonic Bloch Waves and Photonic Band Gaps.- Light Emission in Photonic Crystal Micro-Cavities.- Special Topics - Applications.- Semiconductor Nanostructure lasers: Fundamentals and Fabrications.- Quantum Wells Optical Switching Devices.- High-efficiency, Narrow Spectrum Resonant Cavity Light Emitting Diodes.- Short Papers (Seminars and Selected Posters).- Spontaneous Emission Control in Planar Structures: Er3+ in Si/SO2 Microcavities.- Vacuum Rabi Splitting in a Semiconductor Microcavity.- Impurity Modes in One-Dimensional Periodic Systems: The Transition from Photonic Bandgaps to Microcavities.- Photonic Bandgap Calculations: Inward and Outward Integral Equations and the KKR method.- Soliton-Polariton Interaction near an Excitonic Resonance in Semiconductors.- Dynamics of Excitons and Electron-Hole Plasma Confined in Semiconductor Nanocrystals.- Coupled-Quantum Wells for Optical Modulation.- In-plane Electro-Optic Effect in a Quantum Well.- Reprinted Papers: Basics.- Aspects of Polaritons.- Interband Optical Transitions in Extremely Anisotropic Semiconductors.- Effect of Retarded Interaction on the Exciton Spectrum in One-Dimensional and Two-Dimensional Crystals.- On the Exciton Luminescence at Low temperatures: Importance of the Polariton Viewpoint.- Spatial and Spectral Features of Polariton Fluorescence.- Reprinted Papers: Confined Electrons.- Studies of Exciton Localization in Quantum-Well Structures by Nonlinear-Optical Techniques.- Excitonic Optical Nonlinearity and Exciton Dynamics in Semiconductor Quantum Dots.- Very Large Optical Nonlinearity of Semiconductor Microcrystallites.- Reprinted Papers: Confined Photons.- Spontaneous Emission Probabilities at Radiofrequencies.- Inhibited Spontaneous Emission.- Inhibited Spontaneous Emission in Solid State Physics and Electronics.- Cavity Q.E.D.- Cavity Quantum Electrodynamics at Optical Frequencies.- Physics and Device Applications of Optical Microcavities.- Optical Processes in Microcavities.- Photon Number Squeezed States in Semiconductor Lasers.- Photonic Bandgap Structures.- Applications of Photonic Band gap Structures.- Contributors.

Fabrication of Photonic Band-Gap Crystals

Abstract: We describe the fabrication of three-dimensional photonic crystals using a reproducible and reliable procedure consisting of electron beam lithography followed by a sequence of dry etching steps. Careful fabrication has enabled us to define photonic crystals with 280 nm holes defined with 350 nm center to center spacings in GaAsP and GaAs epilayers. We construct these photonic crystals by transferring a submicron pattern of holes from 70-nm-thick polymethylmethacrylate resist layers into 300-nm-thick silicon dioxide ion etch masks, and then anisotropically angle etching the III-V semiconductor material using this mask. Here, we show the procedure used to generate photonic crystals with up to four lattice periods depth.

Photonic band gaps in optical lattices

Abstract: We study photonic band gaps in a one-dimensional optical lattice of laser-cooled trapped atoms. We solve for the self-consistent equilibrium positions of the atoms, accounting for the backaction of the atoms on the trapping beams. This solution depends strongly on the sign of the trapping laser detuning. For red-detuned trapping lasers, the resulting lattice exhibits a one-dimensional photonic band gap for frequencies between the trapping laser frequency and the atomic resonance. For blue detuning the stop band extends symmetrically about resonance, typically for hundreds of atomic linewidths, except for the small region between atomic resonance and the lattice frequency, which is excluded. We calculate the reflection spectrum for a lattice of Cs atoms for various trapping laser detunings and interpret its behavior as a function of the lattice size and density. For a mean density of ${10}^{11}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}3}$, and 1000 planes, 55% reflection of a weak probe beam should be observed. We also consider Bragg scattering in a three-dimensional optical lattice as a means of probing the long-range order in the atomic density correlation function.

Two‐dimensional infrared photonic band gap structure based on porous silicon

Abstract: We have fabricated a two‐dimensional photonic band structure based on macroporous silicon with individual gaps for both polarizations in the infrared region between 250 and 500 cm−1 (20–40 μm). A square lattice of circular air rods with a lattice constant of 8 μm was etched 340 μm deep in an n‐type silicon substrate by electrochemical pore formation in hydrofluoric acid. The transmission spectra between 50 and 650 cm−1 were in good agreement with the theoretical calculated structure. The pore formation technique should allow the fabrication of photonic lattices with a complete two‐dimensional band gap in the middle and near infrared.

Photonic Bloch waves and photonic band gaps

Abstract: Photonic band gap materials are dielectrics with a synthetic, three dimensional, multiply periodic microstructure (lattice constant of order the optical wavelength) whose distinguishing feature is a very large modulation depth of refractive index. When appropriately designed, these “photonic crystals” exhibit ranges of optical frequency where light cannot exist — the photonic band gaps 7. The current interest in these materials 1–22 has led us to re-appraise propagation in structures that, while not exhibiting a complete photonic band gap (PBG), nevertheless display anomalous and intriguing propagation effects in the vicinity of their Bragg conditions54–58. In most cases, around each Bragg condition appear incomplete momentum and energy gaps (i.e., ranges of, respectively, wavevector and frequency where propagation is forbidden) with widths that are given approximately by the product of the index difference with, respectively, the vacuum wavevector and h times the optical frequency. With the exception of the multi-layer dielectric stack, most conventional electromagnetic gratings, such as those encountered in holography 27, waveguides 45, distributed feedback lasers 35,37,38, acousto-optic 47 and x-ray 61 diffraction, consist of weak periodic perturbations about a mean refractive index. In these gratings, while strong spatial and temporal dispersion are present around each Bragg condition, the ranges of angles and frequencies over which this occurs are very narrow; and although PBG’s do appear, they are incomplete and mostly very weak.

Large electromagnetic stop bands in metallodielectric photonic crystals

Abstract: An electromagnetic stop band spanning about one octave is observed in a periodic structure consisting of a face‐centered‐cubic Bravais lattice of metal spheres supported by a low‐loss dielectric. The low‐frequency edge of the stop band is consistent with the Mie condition for the metallic spheres, and the center frequency of the stop band is a function of the lattice constant and the support dielectric material. For example, a sample having a cubic lattice constant of 1.65 cm, 3/8 in. diam chrome spheres at each atomic core, and Teflon support dielectric displayed a lower band edge of approximately 5.2 GHz, an upper band edge of about 12.8 GHz, and a maximum rejection at the center of the band of roughly 20 dB.

Fabrication, modeling, and characterization of form-birefringent nanostructures.

Abstract: A 490-nm-deep nanostructure with a period of 200 nm was fabricated in a GaAs substrate by use of electron-beam lithography and dry-etching techniques. The form birefringence of this microstructure was studied numerically with rigorous coupled-wave analysis and compared with experimental measurements at a wavelength of 920 nm. The numerically predicted phase retardation of 163.3° was found to be in close agreement with the experimentally measured result of 162.5°, thereby verifying the validity of our numerical modeling. The fabricated microstructures show extremely large artificial anisotropy compared with that available in naturally birefringent materials and are useful for numerous polarization optics applications.

Resonant cavities employing two dimensionally periodic dielectric materials

Abstract: The present invention provides a resonant cavity including a planar two-dimensional periodic dielectric structure which exhibits a photonic band gap and a defect in the periodic dielectric structure which results in an electromagnetic mode within the photonic band gap. The photonic band gap effects an in-plane spacial confinement of electromagnetic radiation generated within the structure. The electromagnetic radiation is vertically confined by total internal reflection.

Subfemtosecond determination of transmission delay times for a dielectric mirror (photonic band gap) as a function of the angle of incidence.

Abstract: Using a two-photon interference technique, we measure the delay for single-photon wave packets to be transmitted through a multilayer dielectric mirror, which functions as a ``photonic band-gap'' medium. By varying the angle of incidence, we are able to confirm the behavior predicted by the group delay (stationary-phase approximation), including a variation of the delay time from superluminal to subluminal as the band edge is tuned toward the wavelength of our photons. The agreement with theory is better than 0.5 fs (less than one-quarter of an optical period) except at large angles of incidence. The source of the remaining discrepancy is not yet fully understood.

Theoretical investigation of fabrication‐related disorder on the properties of photonic crystals

Abstract: How various deviations in perfect photonic crystals, which may arise during fabrication, 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.

Defect structures in a layer-by-layer photonic band-gap crystal

Abstract: We have experimentally and theoretically investigated defect structures that are incorporated into a three-dimensional layer-by-layer photonic band-gap crystal. The defects are formed by either adding or removing dielectric material to or from the crystal. For both cases, we observed localized modes with frequencies that lie within the forbidden band gap of the pure crystal. Relatively high peak transmission (10 dB below the incident signal), and high quality factors (2000) have been measured. These measurements were in good agreement with theoretical simulations. Theoretical calculations also predict very high (Qg${10}^{6}$) quality factors for certain cavity structures.

Air‐bridge microcavities

Abstract: We introduce and analyze a new type of high‐Q microcavity consisting of a channel waveguide and a one‐dimensional photonic crystal. A band gap for the guided modes is opened and a sharp resonant state is created by adding a single defect in the periodic system. An analysis of the eigenstates shows that strong field confinement of the defect state can be achieved with a modal volume less than half of a cubic half‐wavelength. We also present a feasibility study for the fabrication of suspended structures with micron‐sized features using semiconductor materials.

Photonic gaps in the dispersion of surface plasmons on gratings.

Abstract: An analytic model is presented that reveals the physical origin of the photonic band gap created by Bragg scattering of surface plasmon polaritons on gratings. The model leads to simple functional forms for the gap width, central frequency, and field distributions which are confirmed by comparison with numerical calculations and experimental data.

Emission power of an electric dipole in the photonic band structure of the fcc lattice

Abstract: It has been suggested that spontaneous emission can be inhibited if atomic transition frequencies fall inside photonic band gaps, that is, three-dimensional frequency stop bands of electromagnetic waves generated by three-dimensional periodic dielectric materials (photonic crystals). There has been a growing interest in how atomic emission spectra are changed quantitatively inside the photonic crystals. We develop a classical theory for the calculation of the emission power from the electric dipole located in three-dimensional photonic crystals by incorporating the plane-wave method, dyadic Green’s function, Poynting theorem, and tetrahedron k-space integration. With the method we perform numerical computations for the emission power of an electric dipole located in the photonic crystals of the fcc lattice structure with spherical atoms. The results show the total inhibition of emission in the photonic band gap as well as strong enhancement around the band edges. In addition, the data indicate the strong dependencies of the emission spectrum on the dipole position and the dipole moment in the photonic crystal.

Second-harmonic generation in local modes of a truncated periodic structure

Abstract: Electromagnetic mode selection in periodic dielectric materials may be used to obtain sharp optical features such as suppression and enhancement of the radiation of oscillating dipoles. Periodic dielectric materials may be studied by means of the photonic band gap (PBG) theory.1 In the framework of this theory, we present an experimental study of the second harmonic (SH) generation from a slab of nonlinear molecules embedded in a 1-dimensional periodic dielectric structure truncated by the introduction of a defect in the central period.

Ultra-wideband photonic band gap crystal having selectable and controllable bad gaps and methods for achieving photonic band gaps

Abstract: The present invention provides multidimensional stacked photonic band gap crystal structures improving the performance of current planar monolithic antennas and RF filters by forbidding radiation from coupling into the substrate thereby significantly enhancing radiation efficiency and bandwidth. This invention comprises a number of sub-crystals with each having at least two lattices disposed within a host material, each lattice having a plurality of dielectric pieces arranged and spaced from each other in a predetermined manner, the sub-crystals being stacked in a crystal structure to provide a photonic band gap forbidding electromagnetic radiation propagating over a specially designed frequency band gap, or stopband. Both two dimensional and multidimensional crystals are disclosed. The preferred embodiment is a three-dimensional photonic band gap crystal comprising two or more sub-crystals, with each sub-crystal having a diamond-patterned lattice constructed from a plurality of dielectric zigzag pieces orthogonally interconnected, disposed within a host material.

Interferometric technique for the measurement of photonic band structure in colloidal crystals

Abstract: Under suitable conditions polystyrene microsphere colloids form photonic crystals capable of diffracting visible light, analogous to x-ray diffraction from atomic crystal planes. The lattice spacings of these crystals can be tailored to satisfy the Bragg condition along a certain direction for a particular desired wavelength. A modified Mach–Zehnder interferometer has been developed for accurately measuring relative phase shifts of light propagating in photonic crystals to determine the dispersion resulting from photonic band structure near the band edges.

Optimized dipole antennas on photonic band gap crystals

Abstract: Photonic band gap crystals have been used as a perfectly reflecting substrate for planar dipole antennas in the 12–15 GHz regime. The position, orientation, and driving frequency of the dipole antenna on the photonic band gap crystal surface, have been optimized for antenna performance and directionality. Virtually no radiated power is lost to the photonic crystal resulting in gains and radiation efficiencies larger than antennas on other conventional dielectric substrates.

Photonic dispersion surfaces

Abstract: Using the transfer matrix method for calculating the band structure, transmission and reflection coefficients of photonic systems, we present a method for calculating photonic dispersion surfaces. We then show how dispersion surfaces are excellent tools in the search for photonic insulators by applying the method to a simple system. We also explore the potential of metals for incorporation in photonic structures.

Photonic-band-structure calculation of material possessing kerr nonlinearity

Abstract: The Finite Difference Time Domain (FDTD) technique dates back to 1966 when it was first developed by Yee [1]. Since then it has been widely used to calculate the radar cross section of objects as well as normal modes of wave guides. Chan et al. [2] recently applied this technique to calculate the band structure of photonic crystal with excellent results. The motivation for their use of this technique is the fact this technique scales linearly with system size. Systems having random defects, which destroy any periodicity, are often studied using the “super cell” method where the system is assumed to be periodic with a very large period. In such a case, it is important the technique for band structure calculation scales favorably with system size. The plane wave expansion technique, for example, is impractical since it scales as N3 where N is the system size. In this paper I show how the FDTD technique can be extended to calculate the band structure of nonlinear photonic crystals, in particular, those which possess Kerr nonlinearity.

Optical switch that utilizes one-dimensional, nonlinear, multilayer dielectric stacks

Abstract: An optical switch in a one-dimensional multilayer dielectric stack having a photonic band gap, composed of at least two groups of layers of dielectric material whose operating wavelength is near the edge of said photonic band gap. At least one layer of each of the groups is composed of a nonlinear c 3 dielectric material, which creates an intensity-dependent shift in the location of the band gap and produces a dynamical change in the transmissive and reflective properties of the multilayer dielectric stack in response to changes in the intensity of light or the transmittance of electromagnetic radiation passing through the multilayer dielectric stack. The width of the photonic band gap is determined by the differences between the refractive indices of the nonlinear dielectric material and that of the other layers of dielectric material in the multilayer dielectric stack.

Three-dimensional ordered patterns by light interference.

Abstract: Based on numerical simulation it is found that three-dimensional periodic patterns with micrometer or submicrometer lattice constants, such as those with simple cubic, face-centered cubic, body-centered cubic, or body-centered tetragonal symmetry, can be formed by use of multiple laser beam interference. Changes in the number and angle of the incident beams result in different spatial patterns, whereas variation of the incident wavelength affects only the lattice constant of the patterns. Face-centered cubic and body-centered tetragonal patterns have been observed experimentally. Our results, combined with the optical trapping of dielectric particles, might provide a promising approach to the realization of a new kind of material-a photonic crystal.

Laser-micromachined millimeter-wave photonic band-gap cavity structures

Abstract: We have used laser‐micromachined alumina substrates to build a three‐dimensional photonic band‐gap crystal. The rod‐based structure has a three‐dimensional full photonic band gap between 90 and 100 GHz. The high resistivity of alumina results in a typical attenuation rate of 15 dB per unit cell within the band gap. By removing material, we have built defects which can be used as millimeter‐wave cavity structures. The resulting quality (Q) factors of the millimeter‐wave cavity structures were as high as 1000 with a peak transmission of 10 dB below the incident signal.

Possibility of InP-Based 2-Dimensional Photonic Crystal: An Approach by the Anodization Method

Abstract: We have investigated the possibility of InP-based 2-dimensional (2D) photonic crystal experimentally and theoretically. To fabricate such crystal, we aimed at utilizing triangular rods and holes automatically formed at the surface of (111)A InP substrate by an anodization method. Favorable characteristics are that the rods and holes orient perpendicular to the surface and have submicron width and high aspect ratio. In addition, observed photoluminescence spectra indicated negligibly slow surface recombination at the anodized surface. From the calculation of band diagram, the photonic gap was found for uniform triangular rods. Thus low-damage 2D photonic crystal which controls light emission and propagation in the 2D plane can be realized by controlling the size uniformity and position of rods using the patterned oxide mask.

Possibility of InP-based 2-dimensional photonic crystal

Abstract: We have investigated the possibility of InP-based 2-dimensional (2D) photonic crystal experimentally and theoretically. To fabricate such crystal, we aimed at utilizing triangular rods and holes automatically formed at the surface of (111)A InP substrate by an anodization method. Favorable characteristics are that the rods and holes orient perpendicular to the surface and have submicron width and high aspect ratio. In addition, observed photoluminescence spectra indicated negligibly slow surface recombination at the anodized surface. From the calculation of band diagram, the photonic gap was found for uniform triangular rods. Thus low-damage 2D photonic crystal which controls light emission and propagation in the 2D plane can be realized by controlling the size uniformity and position of rods using the patterned oxide mask.

A Bulk-micromachined 1024-element Uncooled Infrared Imager

Abstract: This paper reports a bulk-micromachined silicon uncooled thermal imager intended for applications in automated process control. The device is organized as a 32x32-element area array with on-chip address generation and multiplexing. Both front-undercut and back-etched pixel structures have been explored. The pixel size in both imagers is 375pm x 375pm with a pixel area of 12" x 12" and an overall chip size of 16" x 16". The pixels consist of 32 and 36 n-p polysilicon thermocouples, respectively, and produce typical responsivities of 3 0 V N with thermal time constants of less than Smsec. Each pixel is self-testing using an embedded resistor network. The imager has an on-chip bandgap ambient temperature sensor and an optional opamp for signal amplification. The imager forms the front-end of a microprocessorcontrolled camera system that features automatic per-pixel ranging and gain control. The devices should resolve wafer temperature nonuniformities of less than 1°C in semiconductor manufacturing applications such as rapid thermal processing.