(1) Photonic band gap (PBG) crystals can manipulate light in the same way semiconductors control electric currents. They prevent light propagation within a photonic band gap through Bragg scattering and defects.
(2) PBG crystals are fabricated by drilling holes in a dielectric material in a periodic lattice. This creates a range of frequencies where light is blocked.
(3) Applications include photonic crystal fibers for endlessly single mode fibers, photonic crystal lasers, filters, and planar waveguides for compact integrated photonic circuits. Future directions include all-optical transistors for terabit routing and quantum computing.
Surbhi Verma completed an internship at the Indian Institute of Technology in Delhi studying photonic crystals under Professor Joby Joseph. She used the Crystal Wave simulation software to model a one-dimensional photonic crystal sensor with two defects. Her results showed that the time-averaged energy density changed linearly with the refractive index of the second defect when its radius was 800nm, indicating potential for an optical refractive index sensor. She also found non-linear changes in energy density when varying the second defect's radius.
Photonic crystals are periodic optical nanostructures that affect the propagation of light. They contain regions of high and low dielectric constants arranged in a repeating pattern, allowing certain wavelengths of light to pass through while others are forbidden from propagating, known as a photonic band gap. Photonic crystals have applications in lasers, optical fibers, biosensing and more. They can be fabricated through methods like layer deposition, photolithography or drilling holes to achieve one, two or three-dimensional periodicity.
Photonic crystals are periodic dielectric structures that have a band gap that forbids propagation of a certain frequency range of light. This property enables one to control light with amazing facility and produce effects that are impossible with conventional optics.Photonic crystals can be fabricated for one, two, or three dimensions. One-dimensional photonic crystals can be made of layers deposited or stuck together. Two-dimensional ones can be made by photolithography, or by drilling holes in a suitable substrate. Fabrication methods for three-dimensional ones include drilling under different angles, stacking multiple 2-D layers on top of each other, direct laser writing, or, for example, instigating self-assembly of spheres in a matrix and dissolving the spheres
The document discusses recent trends in photonic devices. It begins by defining optics and photonics, and describes some applications of photonics including information technology, healthcare, sensing, lighting and displays. It then explains that photonic devices manipulate or detect light, providing examples like lasers, LEDs and solar cells. The document goes on to discuss latest trends like nanophotonics using graphene, carbon nanotubes and photonic crystals. It also covers silicon photonic devices using silicon-germanium transistors and germanium-tin phototransistors. In conclusion, it predicts future applications of photonics in areas like e-paper, solar panels and light-emitting fabrics.
This document discusses nonlinear optics and summarizes key topics covered:
- It describes the difference between linear and nonlinear optics, where linear optics involves weak light that is unchanged and nonlinear optics involves intense light that can induce effects and be manipulated.
- Nonlinear optics allows changing light properties like color and shape, and has applications in telecommunications and creating ultrashort events.
- Phenomena like sum and difference frequency generation are examples of second-order nonlinear optical effects. Phase matching is important for efficient nonlinear optical processes.
- Applications of nonlinear optics include optical phase conjugation, optical parametric oscillators, optical computing, optical switching, and optical data storage.
The document discusses photonic crystals, which are periodic electromagnetic media that can exhibit photonic band gaps. It provides examples of photonic crystals found in nature and techniques for fabricating synthetic photonic crystals, including layer-by-layer lithography, the woodpile crystal structure, two-photon lithography, and holographic lithography. Intentional defects in photonic crystals can be used to trap light and guide it in waveguides or cavities, allowing control of light propagation.
This document discusses photonic crystal fibers (PCFs). PCFs are composed of nanostructures that affect photon propagation through periodic refractive indices, similar to how semiconductor crystals affect electron motion. PCFs can guide light through two mechanisms: index guiding and photonic bandgap guiding. They have properties like endless single mode operation, large mode areas, and tunable dispersion. Special PCFs include double core fibers, highly birefringent fibers, and hollow core bandgap fibers. PCFs offer advantages over standard fibers like flexibility in core size and wavelengths used. Challenges include difficult fabrication and limited operating frequencies.
Photonics devices use photons to transmit, control, manipulate and store data. They offer benefits like greater energy savings and communication distances due to their unique characteristics, such as being less sensitive to interference. Light-emitting diodes (LEDs) are semiconductor light sources used as indicator lamps and increasingly for lighting. They have advantages over other light sources like lower energy use, longer lifetimes, and smaller size. Photodiodes are PN junction diodes designed to detect photons and convert light into an electrical current. Laser diodes are semiconductor devices that produce coherent light when current passes through and are used to convert electrical signals into light signals.
Surbhi Verma completed an internship at the Indian Institute of Technology in Delhi studying photonic crystals under Professor Joby Joseph. She used the Crystal Wave simulation software to model a one-dimensional photonic crystal sensor with two defects. Her results showed that the time-averaged energy density changed linearly with the refractive index of the second defect when its radius was 800nm, indicating potential for an optical refractive index sensor. She also found non-linear changes in energy density when varying the second defect's radius.
Photonic crystals are periodic optical nanostructures that affect the propagation of light. They contain regions of high and low dielectric constants arranged in a repeating pattern, allowing certain wavelengths of light to pass through while others are forbidden from propagating, known as a photonic band gap. Photonic crystals have applications in lasers, optical fibers, biosensing and more. They can be fabricated through methods like layer deposition, photolithography or drilling holes to achieve one, two or three-dimensional periodicity.
Photonic crystals are periodic dielectric structures that have a band gap that forbids propagation of a certain frequency range of light. This property enables one to control light with amazing facility and produce effects that are impossible with conventional optics.Photonic crystals can be fabricated for one, two, or three dimensions. One-dimensional photonic crystals can be made of layers deposited or stuck together. Two-dimensional ones can be made by photolithography, or by drilling holes in a suitable substrate. Fabrication methods for three-dimensional ones include drilling under different angles, stacking multiple 2-D layers on top of each other, direct laser writing, or, for example, instigating self-assembly of spheres in a matrix and dissolving the spheres
The document discusses recent trends in photonic devices. It begins by defining optics and photonics, and describes some applications of photonics including information technology, healthcare, sensing, lighting and displays. It then explains that photonic devices manipulate or detect light, providing examples like lasers, LEDs and solar cells. The document goes on to discuss latest trends like nanophotonics using graphene, carbon nanotubes and photonic crystals. It also covers silicon photonic devices using silicon-germanium transistors and germanium-tin phototransistors. In conclusion, it predicts future applications of photonics in areas like e-paper, solar panels and light-emitting fabrics.
This document discusses nonlinear optics and summarizes key topics covered:
- It describes the difference between linear and nonlinear optics, where linear optics involves weak light that is unchanged and nonlinear optics involves intense light that can induce effects and be manipulated.
- Nonlinear optics allows changing light properties like color and shape, and has applications in telecommunications and creating ultrashort events.
- Phenomena like sum and difference frequency generation are examples of second-order nonlinear optical effects. Phase matching is important for efficient nonlinear optical processes.
- Applications of nonlinear optics include optical phase conjugation, optical parametric oscillators, optical computing, optical switching, and optical data storage.
The document discusses photonic crystals, which are periodic electromagnetic media that can exhibit photonic band gaps. It provides examples of photonic crystals found in nature and techniques for fabricating synthetic photonic crystals, including layer-by-layer lithography, the woodpile crystal structure, two-photon lithography, and holographic lithography. Intentional defects in photonic crystals can be used to trap light and guide it in waveguides or cavities, allowing control of light propagation.
This document discusses photonic crystal fibers (PCFs). PCFs are composed of nanostructures that affect photon propagation through periodic refractive indices, similar to how semiconductor crystals affect electron motion. PCFs can guide light through two mechanisms: index guiding and photonic bandgap guiding. They have properties like endless single mode operation, large mode areas, and tunable dispersion. Special PCFs include double core fibers, highly birefringent fibers, and hollow core bandgap fibers. PCFs offer advantages over standard fibers like flexibility in core size and wavelengths used. Challenges include difficult fabrication and limited operating frequencies.
Photonics devices use photons to transmit, control, manipulate and store data. They offer benefits like greater energy savings and communication distances due to their unique characteristics, such as being less sensitive to interference. Light-emitting diodes (LEDs) are semiconductor light sources used as indicator lamps and increasingly for lighting. They have advantages over other light sources like lower energy use, longer lifetimes, and smaller size. Photodiodes are PN junction diodes designed to detect photons and convert light into an electrical current. Laser diodes are semiconductor devices that produce coherent light when current passes through and are used to convert electrical signals into light signals.
The document discusses metamaterials and their applications. It begins with defining metamaterials as artificially engineered materials with properties not found in nature. It then discusses techniques for achieving negative permeability and permittivity values, challenges in optical metamaterials, and applications including 3D metamaterials, slow light, cloaking, chiral metamaterials, and superlensing. The talk is divided into sections on different metamaterial topics that will be covered.
This chapter discusses the optical properties of phonons in materials. It covers:
1) Optical and acoustic phonons - some interact directly with light, others cause light scattering.
2) Optical excitation of phonons - how phonons contribute to optical properties through the dielectric function.
3) Phonon polaritons - mixed phonon-photon excitations in crystals near resonance frequencies.
4) Light scattering - concepts of Brillouin, Raman, and Rayleigh scattering involving phonons.
5) Coherent Raman spectroscopy - an experimental technique that enhances weak Raman scattering signals.
This document compares and contrasts linear and nonlinear optics. In linear optics, light propagates through a medium without changing frequency, while in nonlinear optics the medium's response depends on light intensity. Nonlinear optics involves effects where the induced polarization in a medium does not linearly depend on the electric field of the light. This allows frequency conversion via processes like second harmonic generation and sum frequency generation. Materials can exhibit a nonlinear refractive index, leading to self-focusing or defocusing of high intensity light beams. Nonlinear optical effects enable applications like frequency conversion, optical limiting, and all-optical signal processing.
This document summarizes key concepts about laser beams and optical resonators:
1) Laser beam propagation can be described by the Helmholtz equation, with one solution being a Gaussian beam profile. The beam waist radius varies along the beam axis according to the Rayleigh range.
2) Optical resonators provide feedback to turn an amplifier into an oscillator. They contain mirrors between which light bounces and is amplified on each pass through the gain medium.
3) Resonator stability depends on the curvature and separation of the mirrors. Different resonator types support distinct transverse mode patterns within the beam.
This document discusses dielectrics and their properties. It introduces dielectrics as materials that can store electric charge and energy with minimal heat loss. The document discusses how a capacitor's capacitance depends on the dielectric material between its plates, including the dielectric constant which measures a material's ability to concentrate electrostatic lines of flux. It also examines polarization in insulators when an electric field is applied and defines related terms like permittivity, dielectric constant, and loss tangent.
This document discusses nanophotonics and its applications. It begins by defining nanophotonics as the study of light behavior on the nanometer scale, including interactions between light and particles. It then discusses several nanophotonics technologies like near-field scanning optical microscopy and surface plasmon optics. The document also outlines several advantages of nanophotonics, such as enabling enormous data transmission rates and high optical memory storage density. It concludes by discussing some applications of nanophotonics like NEMS (nanoelectromechanical systems) devices that integrate electrical and mechanical functionality on the nanoscale.
This document summarizes research on plasmonics and surface plasmon polaritons (SPPs). It discusses two types of excitations - localized surface plasmon resonance and propagating SPPs. Applications mentioned include spectroscopy, molecular detection, cancer treatment, photonic devices, integrated photonics, and optical data storage. Challenges include losses, thermal effects, and limitations of nanofabrication techniques. The document also reviews using SPPs for applications such as beam collimation, near-field microscopy, solar cells, and metamaterials.
This document provides an overview of photonic crystal fibers. It discusses two main light guidance mechanisms in photonic crystal fibers: index guiding and photonic bandgap guidance. Properties of single mode photonic crystal fibers discussed include them being endlessly single mode, having large mode areas, and customizable dispersion properties. Hollow core photonic crystal fibers are also summarized, which have ultra-low loss due to most light propagating through air. Additional fiber types like double core fibers and highly birefringent fibers are briefly mentioned. In summary, the document outlines the key properties and design flexibility of photonic crystal fibers compared to conventional fibers.
Magnetic materials form magnetic domains to minimize their magnetostatic energy. Domain walls separate domains with different magnetization orientations. Bloch walls have spins rotating continuously across the wall, while Neel walls have spins rotating in the plane of the wall. The equilibrium domain size and wall thickness are determined by a balance of exchange, anisotropy, magnetostatic, and wall energies. Various techniques like SEMPA, MFM, and magneto-optical imaging are used to observe domain structures with high resolution.
Molecular beam epitaxy (MBE) is a method for growing thin films one layer at a time under ultra-high vacuum conditions. It involves heating solid sources of material in effusion cells to create molecular beams that are deposited on a heated substrate. The absence of carrier gases and ultra-high vacuum environment result in films of the highest purity. MBE is widely used to manufacture semiconductor devices and is considered a fundamental tool for nanotechnology development due to its precise control over layer thickness down to a single atomic layer.
Basic of semiconductors and optical propertiesKamran Ansari
This presentation explains the band structure, intrinsic semiconductor, extrinsic semiconductor, electrical conductivity, mobility, hall effect, p-n junction diode, tunnel diode and optical properties of the semiconductor.
This document discusses optical metamaterials and their potential applications. Metamaterials are artificially engineered composites that can exhibit optical properties not found in nature. They are composed of unit cells much smaller than the wavelength of light. By designing the unit cells, metamaterials can have engineered electric permittivity and magnetic permeability values. This allows properties like negative refractive index not found in natural materials. Potential applications discussed include ultrathin lenses and invisibility cloaking by manipulating light propagation.
This document defines and describes semiconductor superlattices. A superlattice is a periodic structure of thin layers of two or more semiconductors that form multiple quantum wells. The layers must be thin enough, around 1-5 nm, for carrier tunneling to occur between wells. Common fabrication techniques like molecular beam epitaxy can precisely deposit layers only a few atomic layers thick to create superlattices. Unlike multiple quantum wells where wavefunctions do not overlap between wells, superlattices have thin enough barriers that wavefunctions delocalize across wells due to tunneling. This gives rise to minibands and allows carrier transport properties to differ from conventional semiconductors.
Plasmonics... A ladder to futuristic technology Pragya
Plasmonics is the study of plasma oscillations in metals. Plasmons are density waves in the electron gas in metals that are excited by light. They have shorter wavelengths than light and can propagate signals at the nanoscale. This allows for applications in nanophotonics like enhanced optical transmission and biosensing. Plasmons can be excited by coupling light to collective electron oscillations at metal surfaces or in nanostructures like nanoparticles. Metamaterials aim to control plasmons for applications such as cloaking, perfect lenses, and transformation optics. Plasmonics may lead to faster optoelectronic devices by transmitting data with plasmonic waves instead of electric currents.
Photonic materials manipulate photons to achieve certain functions. Photonic crystals are a type of photonic material that displays unusual properties in interacting with light due to a periodic modulation of refractive index. They can trap light in cavities and waveguides by creating photonic band gaps that prevent light from propagating in certain directions. Potential applications of photonic crystals include photonic integrated circuits, lasers, sensors, and replacing conventional optical fibers.
- Surface plasmon polaritons are electromagnetic waves that propagate along the interface between a metal and a dielectric material. They arise from the coupling of incident light to oscillations of surface electrons known as surface plasmons.
- Surface plasmon polaritons can be excited through techniques like prism coupling using either the Otto or Kretschmann configurations, which use evanescent waves to overcome the momentum mismatch between incident light and surface plasmons.
- Applications of surface plasmon resonance include ultrasensitive biosensing, fluorescence imaging, catalysis, and phototherapy due to the ability of surface plasmons to concentrate electromagnetic fields at subwavelength scales.
This document provides an overview of organic solar cells. It discusses that organic solar cells are more economical and flexible than traditional silicon solar cells. The structure of organic solar cells is described, including the light-absorbing donor polymer layer, the electron-acceptor fullerene layer, and electrodes. Applications mentioned include phone chargers, small electronics, and building-integrated photovoltaics. Manufacturing of organic solar cells has lower costs than silicon cells due to using thinner films of molecules. While organic solar cells have disadvantages like lower efficiency and shorter lifetimes than silicon, they provide benefits such as flexibility, low weight, and reduced environmental impact.
Metamaterials are artificial materials engineered to provide properties not found in nature. They derive their properties from their structure rather than composition. Metamaterials can create negative indexes of refraction and guide waves in desired directions. They have applications in antennas, invisibility cloaking, and frequency selective surfaces. The document discusses the history and types of metamaterials, including electromagnetic and acoustic varieties. It outlines previous work on cubic metamaterials and the presenter's objectives to further explore their properties and applications through modeling and simulation.
This document provides details on measuring the resistance of semiconductors using the four probe method and how it varies with temperature. It first explains Ohm's law and the two probe method for measuring resistance. The four probe method is then introduced to overcome issues with contact resistance. The document derives equations to calculate resistivity based on probe spacing and sample thickness/boundaries. Finally, it discusses how the intrinsic conductivity of semiconductors increases with temperature due to more electrons occupying the conduction band, following an exponential relationship, and how carrier mobility decreases with increasing temperature due to more collisions.
This document summarizes a research project on synthesizing new photonic band gap materials using dielectric-metal-dielectric particles. (2) The researcher synthesized silica, silver-coated silica, and silica-silver-silica particles and used a controlled evaporation method to assemble them into photonic crystals. (3) Optical measurements showed that silica-silver particle photonic crystals exhibited a red-shifted photonic band gap compared to pure silica photonic
Opal and inverse opal structures for optical device applicationsM. Faisal Halim
This document summarizes research on developing an all-optical silicon transistor using an opal/inverse opal photonic crystal heterostructure. Photonic crystals can act as optical waveguides and switches by manipulating light transmission through periodic dielectric structures. Most work so far uses non-silicon materials at scales above 200nm, but inverse opals have potential at the nanoscale using silicon. The document outlines challenges in developing 1D, 2D and 3D photonic crystals and integrating them with silicon chips. It then describes how opals and inverse opals are made and their photonic bandgap properties. Current research is working to shrink features below 100nm for visible light applications in silicon. The goal is an all-opt
The document discusses metamaterials and their applications. It begins with defining metamaterials as artificially engineered materials with properties not found in nature. It then discusses techniques for achieving negative permeability and permittivity values, challenges in optical metamaterials, and applications including 3D metamaterials, slow light, cloaking, chiral metamaterials, and superlensing. The talk is divided into sections on different metamaterial topics that will be covered.
This chapter discusses the optical properties of phonons in materials. It covers:
1) Optical and acoustic phonons - some interact directly with light, others cause light scattering.
2) Optical excitation of phonons - how phonons contribute to optical properties through the dielectric function.
3) Phonon polaritons - mixed phonon-photon excitations in crystals near resonance frequencies.
4) Light scattering - concepts of Brillouin, Raman, and Rayleigh scattering involving phonons.
5) Coherent Raman spectroscopy - an experimental technique that enhances weak Raman scattering signals.
This document compares and contrasts linear and nonlinear optics. In linear optics, light propagates through a medium without changing frequency, while in nonlinear optics the medium's response depends on light intensity. Nonlinear optics involves effects where the induced polarization in a medium does not linearly depend on the electric field of the light. This allows frequency conversion via processes like second harmonic generation and sum frequency generation. Materials can exhibit a nonlinear refractive index, leading to self-focusing or defocusing of high intensity light beams. Nonlinear optical effects enable applications like frequency conversion, optical limiting, and all-optical signal processing.
This document summarizes key concepts about laser beams and optical resonators:
1) Laser beam propagation can be described by the Helmholtz equation, with one solution being a Gaussian beam profile. The beam waist radius varies along the beam axis according to the Rayleigh range.
2) Optical resonators provide feedback to turn an amplifier into an oscillator. They contain mirrors between which light bounces and is amplified on each pass through the gain medium.
3) Resonator stability depends on the curvature and separation of the mirrors. Different resonator types support distinct transverse mode patterns within the beam.
This document discusses dielectrics and their properties. It introduces dielectrics as materials that can store electric charge and energy with minimal heat loss. The document discusses how a capacitor's capacitance depends on the dielectric material between its plates, including the dielectric constant which measures a material's ability to concentrate electrostatic lines of flux. It also examines polarization in insulators when an electric field is applied and defines related terms like permittivity, dielectric constant, and loss tangent.
This document discusses nanophotonics and its applications. It begins by defining nanophotonics as the study of light behavior on the nanometer scale, including interactions between light and particles. It then discusses several nanophotonics technologies like near-field scanning optical microscopy and surface plasmon optics. The document also outlines several advantages of nanophotonics, such as enabling enormous data transmission rates and high optical memory storage density. It concludes by discussing some applications of nanophotonics like NEMS (nanoelectromechanical systems) devices that integrate electrical and mechanical functionality on the nanoscale.
This document summarizes research on plasmonics and surface plasmon polaritons (SPPs). It discusses two types of excitations - localized surface plasmon resonance and propagating SPPs. Applications mentioned include spectroscopy, molecular detection, cancer treatment, photonic devices, integrated photonics, and optical data storage. Challenges include losses, thermal effects, and limitations of nanofabrication techniques. The document also reviews using SPPs for applications such as beam collimation, near-field microscopy, solar cells, and metamaterials.
This document provides an overview of photonic crystal fibers. It discusses two main light guidance mechanisms in photonic crystal fibers: index guiding and photonic bandgap guidance. Properties of single mode photonic crystal fibers discussed include them being endlessly single mode, having large mode areas, and customizable dispersion properties. Hollow core photonic crystal fibers are also summarized, which have ultra-low loss due to most light propagating through air. Additional fiber types like double core fibers and highly birefringent fibers are briefly mentioned. In summary, the document outlines the key properties and design flexibility of photonic crystal fibers compared to conventional fibers.
Magnetic materials form magnetic domains to minimize their magnetostatic energy. Domain walls separate domains with different magnetization orientations. Bloch walls have spins rotating continuously across the wall, while Neel walls have spins rotating in the plane of the wall. The equilibrium domain size and wall thickness are determined by a balance of exchange, anisotropy, magnetostatic, and wall energies. Various techniques like SEMPA, MFM, and magneto-optical imaging are used to observe domain structures with high resolution.
Molecular beam epitaxy (MBE) is a method for growing thin films one layer at a time under ultra-high vacuum conditions. It involves heating solid sources of material in effusion cells to create molecular beams that are deposited on a heated substrate. The absence of carrier gases and ultra-high vacuum environment result in films of the highest purity. MBE is widely used to manufacture semiconductor devices and is considered a fundamental tool for nanotechnology development due to its precise control over layer thickness down to a single atomic layer.
Basic of semiconductors and optical propertiesKamran Ansari
This presentation explains the band structure, intrinsic semiconductor, extrinsic semiconductor, electrical conductivity, mobility, hall effect, p-n junction diode, tunnel diode and optical properties of the semiconductor.
This document discusses optical metamaterials and their potential applications. Metamaterials are artificially engineered composites that can exhibit optical properties not found in nature. They are composed of unit cells much smaller than the wavelength of light. By designing the unit cells, metamaterials can have engineered electric permittivity and magnetic permeability values. This allows properties like negative refractive index not found in natural materials. Potential applications discussed include ultrathin lenses and invisibility cloaking by manipulating light propagation.
This document defines and describes semiconductor superlattices. A superlattice is a periodic structure of thin layers of two or more semiconductors that form multiple quantum wells. The layers must be thin enough, around 1-5 nm, for carrier tunneling to occur between wells. Common fabrication techniques like molecular beam epitaxy can precisely deposit layers only a few atomic layers thick to create superlattices. Unlike multiple quantum wells where wavefunctions do not overlap between wells, superlattices have thin enough barriers that wavefunctions delocalize across wells due to tunneling. This gives rise to minibands and allows carrier transport properties to differ from conventional semiconductors.
Plasmonics... A ladder to futuristic technology Pragya
Plasmonics is the study of plasma oscillations in metals. Plasmons are density waves in the electron gas in metals that are excited by light. They have shorter wavelengths than light and can propagate signals at the nanoscale. This allows for applications in nanophotonics like enhanced optical transmission and biosensing. Plasmons can be excited by coupling light to collective electron oscillations at metal surfaces or in nanostructures like nanoparticles. Metamaterials aim to control plasmons for applications such as cloaking, perfect lenses, and transformation optics. Plasmonics may lead to faster optoelectronic devices by transmitting data with plasmonic waves instead of electric currents.
Photonic materials manipulate photons to achieve certain functions. Photonic crystals are a type of photonic material that displays unusual properties in interacting with light due to a periodic modulation of refractive index. They can trap light in cavities and waveguides by creating photonic band gaps that prevent light from propagating in certain directions. Potential applications of photonic crystals include photonic integrated circuits, lasers, sensors, and replacing conventional optical fibers.
- Surface plasmon polaritons are electromagnetic waves that propagate along the interface between a metal and a dielectric material. They arise from the coupling of incident light to oscillations of surface electrons known as surface plasmons.
- Surface plasmon polaritons can be excited through techniques like prism coupling using either the Otto or Kretschmann configurations, which use evanescent waves to overcome the momentum mismatch between incident light and surface plasmons.
- Applications of surface plasmon resonance include ultrasensitive biosensing, fluorescence imaging, catalysis, and phototherapy due to the ability of surface plasmons to concentrate electromagnetic fields at subwavelength scales.
This document provides an overview of organic solar cells. It discusses that organic solar cells are more economical and flexible than traditional silicon solar cells. The structure of organic solar cells is described, including the light-absorbing donor polymer layer, the electron-acceptor fullerene layer, and electrodes. Applications mentioned include phone chargers, small electronics, and building-integrated photovoltaics. Manufacturing of organic solar cells has lower costs than silicon cells due to using thinner films of molecules. While organic solar cells have disadvantages like lower efficiency and shorter lifetimes than silicon, they provide benefits such as flexibility, low weight, and reduced environmental impact.
Metamaterials are artificial materials engineered to provide properties not found in nature. They derive their properties from their structure rather than composition. Metamaterials can create negative indexes of refraction and guide waves in desired directions. They have applications in antennas, invisibility cloaking, and frequency selective surfaces. The document discusses the history and types of metamaterials, including electromagnetic and acoustic varieties. It outlines previous work on cubic metamaterials and the presenter's objectives to further explore their properties and applications through modeling and simulation.
This document provides details on measuring the resistance of semiconductors using the four probe method and how it varies with temperature. It first explains Ohm's law and the two probe method for measuring resistance. The four probe method is then introduced to overcome issues with contact resistance. The document derives equations to calculate resistivity based on probe spacing and sample thickness/boundaries. Finally, it discusses how the intrinsic conductivity of semiconductors increases with temperature due to more electrons occupying the conduction band, following an exponential relationship, and how carrier mobility decreases with increasing temperature due to more collisions.
This document summarizes a research project on synthesizing new photonic band gap materials using dielectric-metal-dielectric particles. (2) The researcher synthesized silica, silver-coated silica, and silica-silver-silica particles and used a controlled evaporation method to assemble them into photonic crystals. (3) Optical measurements showed that silica-silver particle photonic crystals exhibited a red-shifted photonic band gap compared to pure silica photonic
Opal and inverse opal structures for optical device applicationsM. Faisal Halim
This document summarizes research on developing an all-optical silicon transistor using an opal/inverse opal photonic crystal heterostructure. Photonic crystals can act as optical waveguides and switches by manipulating light transmission through periodic dielectric structures. Most work so far uses non-silicon materials at scales above 200nm, but inverse opals have potential at the nanoscale using silicon. The document outlines challenges in developing 1D, 2D and 3D photonic crystals and integrating them with silicon chips. It then describes how opals and inverse opals are made and their photonic bandgap properties. Current research is working to shrink features below 100nm for visible light applications in silicon. The goal is an all-opt
Bij een vergelijking tussen de grote energiereuzen is Eneco uitgeroepen tot de groenste stroomleverancier.
http://www.onlineenergievergelijker.nl/eneco-uitgeroepen-tot-groenste-stroomleverancier/
http://www.onlineenergievergelijker.nl/
El documento proporciona instrucciones para organizar archivos y carpetas en el sistema operativo. Estas incluyen crear una carpeta personal, generar un árbol de carpetas y subcarpetas con temas de informática, cambiar iconos de carpetas seleccionadas, renombrar carpetas de software, mover una carpeta dentro de otra, agregar imágenes a carpetas de software, y crear accesos directos y anclajes a programas en el escritorio y barra de tareas.
The document discusses the field of photonics. It begins by defining photonics and tracing its origins to developments in the 1960s including the invention of the laser. Photonics enabled major advances in telecommunications and the internet. The document discusses how photonics relates to and differs from fields like optics, quantum optics, and optoelectronics. It provides examples of photonics applications in areas like computing, telecommunications, medicine, industry, and more. In the end, it states that applications of photonics are ubiquitous across both everyday life and advanced science.
La unidad 3 se centra en Europa, donde los estudiantes aprenderán sobre el mapa físico del continente, incluyendo los mares, océanos, ríos y cordilleras principales. También aprenderán sobre el mapa político de Europa, con los nombres y ubicaciones de los países y capitales más importantes. Además, la unidad cubrirá las lenguas y culturas europeas.
[GUTS-RS] Tendências de Teste de Software para 2016GUTS-RS
O documento descreve as principais tendências de teste de software para 2016 discutidas em um evento do GUTS-RS. As tendências mais votadas foram automação de testes, testes ágeis, testes em dispositivos móveis, papel do testador em equipes ágeis e DevOps. Grupos debateram cada tendência e compartilharam perspectivas.
El documento define las fases y fases intermedias. Las fases son porciones homogéneas de un sistema con propiedades uniformes, mientras que las fases intermedias son porciones homogéneas que se forman en un punto crítico. Las fases intermedias también se conocen como compuestos intermedios y incluyen fases químicas, intermetalicas, intersticiales y electrónicas. Las fases intermetalicas y intersticiales a menudo son duras o frágiles, mientras que las fases electrónicas contien
Examples of Photonics Applications for DAY OF PHOTONICS 21 October 2014Carlos Lee Epic
Examples of photonics, optics, lasers, fiber, ... for more information please contact carlos.lee@epic-assoc.com or visit www.epic-assoc.com or www.day-of-photonics.org
*(PPT was prepared for a 15 min presentation)
The topic "Photonic Integrated circuit technology" is in itself very vast that it cant be explained completely in a matter of minutes, so it is better to focus on a particular type of PIC throughout the presentation .(because,based on substrate material,the technology changes and it is always important to maintain a flow throughout the presentation).
Research well on the topic,do your best and leave the rest
:)
SAGE | IOB CORPORATE - MAPEAMENTO DE RISCO ECDMartcom Digital
O documento descreve o complexo contexto tributário para empresas no Brasil, com centenas de leis, contribuições, impostos e obrigações que mudam frequentemente. A Receita Federal autuou empresas em 2015 por 125,6 bilhões de reais, principalmente nos setores industrial, comercial e de serviços. A Escrituração Contábil Digital (ECD) exige que as empresas apresentem informações contábeis eletronicamente de forma clara e consistente para evitar riscos de não conformidade.
Opal is something that definitely takes the cake when it comes to getting bright, shiny gemstones. If you are thinking gifts, unique opal anniversary gifts, opal is the stone of preference. To see them in all their glory; visit opalmine.com for better opal gifting ideas. Shipping is free
This document discusses the fundamentals of photonic crystals and metamaterials. It defines photonic crystals as periodic optical nanostructures that affect photon motion similarly to how semiconductors affect electrons. Photonic crystals exhibit photonic band gaps where certain wavelengths of light are forbidden to propagate. Metamaterials are designed to interact with optical frequencies and contain nano-resonators that can produce negative permeability at optical frequencies. Challenges in constructing photonic materials at near-infrared and visible wavelengths involve nanoscale fabrication and resonance saturation.
1. Nanoparticles have unique properties due to their high surface area to volume ratio, including lower melting points and tunable optical absorption.
2. In semiconductors, quantum confinement results from physically constraining electrons, increasing the energy level spacing and causing absorption and emission spectra to shift to higher energies with decreasing particle size.
3. Nanomaterials exhibit both intramolecular bonding like covalent and ionic bonds, and intermolecular bonding like van der Waals forces, which influence their physical and chemical properties.
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Exploiting Artificial Intelligence for Empowering Researchers and Faculty, In...Dr. Vinod Kumar Kanvaria
Exploiting Artificial Intelligence for Empowering Researchers and Faculty,
International FDP on Fundamentals of Research in Social Sciences
at Integral University, Lucknow, 06.06.2024
By Dr. Vinod Kumar Kanvaria
2. Summary
• Physics of photonic bandgap crystals.
• Photonic Crystals Classification.
• Fabrication.
• Applications.
• Protoype photonic band gap devices.
• Current Research.
• Future Directions.
• Conclusion.
3. What is a PBG ?
• A photonic band gap (PBG) crystal is a structure
that could manipulate beams of light in the same
way semiconductors control electric currents.
• A semiconductor cannot support electrons of
energy lying in the electronic band gap. Similarly,
a photonic crystal cannot support photons lying in
the photonic band gap. By preventing or allowing
light to propagate through a crystal, light
processing can be done .
This will revolutionize photonics the way transistors
revolutionized electronics.
4. How is a PBG fabricated ?
• Photonic crystals usually consist of dielectric
materials, that is, materials that serve as electrical
insulators or in which an electromagnetic field can
be propagated with low loss.
• Holes (of the order of the relevant wavelength) are
drilled into the dielectric in a lattice-like structure
and repeated identically and at regular intervals.
• If built precisely enough, the resulting holey
crystal will have what is known as a photonic band
gap, a range of frequencies within which a specific
wavelength of light is blocked .
5. How does a PBG work ?
• In semiconductors, electrons get scattered by the row of
atoms in the lattice separated by a few nanometers and
consequently an electronic band gap is formed. The
resulting band structure can be modified by doping.
• In a photonic crystal, perforations are analogous to atoms
in the semiconductor. Light entering the perforated
material will reflect and refract off interfaces between
glass and air. The complex pattern of overlapping beams
will lead to cancellation of a band of wavelengths in all
directions leading to prevention of propagation of this
band into the crystal. The resulting photonic band
structure can be modified by filling in some holes or
creating defects in the otherwise perfectly periodic system.
6. Physics of PBG
PBG formation can be regarded as the synergetic interplay between two distinct
resonance scattering mechanisms. The first is the “macroscopic” Bragg resonance from
a periodic array of scatterers. This leads to electromagnetic stop gaps when the wave
propagates in the direction of periodic modulation when an integer number, m=1,2,3…,
of half wavelengths coincides with the lattice spacing, L, of the dielectric microstructure.
The second is a “microscopic” scattering resonance from a single unit cell of the
material. In the illustration, this (maximum backscattering) occurs when precisely one
quarter of the wavelength coincides with the diameter, 2a, of a single dielectric well of
refractive index n. PBG formation is enhanced by choosing the materials parameters a,
L, and n such that both the macroscopic and microscopic resonances occur at the same
frequency.
7. Why is making a PBG hard ?
• Photonic band gap formation is facilitated if the
geometrical parameters of the photonic crystal are chosen
so that both the microscopic and macroscopic resonances
occur at precisely the same wavelength.
• Both of these scattering mechanisms must individually be
quite strong. In practice, this means that the underlying
solid material must have a very high refractive index
contrast (typically about 3.0 or higher and it is to precisely
achieve this contrast, holes are drilled into the medium.)
• The material should exhibit negligible absorption or
extinction of light (less than 1 dB/cm of attenuation.)
These conditions on the geometry, scattering strength, and
the purity of the dielectric material severely restrict the set of
engineered dielectrics that exhibit a PBG.
9. PBG Classifications
Simple examples of one-, two-, and three-dimensional
photonic crystals. The different colors represent materials
with different dielectric constants. The defining feature of
a photonic crystal is the periodicity of dielectric material
along one or more axes. Each of these classifications will be
discussed in turn in the following slides.
10. 1D PBG Crystal
The multilayer thin film show above is a one-dimensional
photonic crystal. The term “one-dimensional” refers to the
fact that the dielectric is only periodic in one direction. It
consists of alternating layers of materials (blue and green)
with different dielectric constants, spaced by a distance a.
The photonic band gap exhibited by this material increases
as the dielectric contrast increases.
11. 1D Band Structures
The photonic band structures for on-axis propagation
shown for three different multilayer films, all of which have
layers of width 0.5a.
Left: Each layer has the same dielectric constant. ε = 13.
Center: Layers alternate between ε = 13 and ε = 12.
Right: Layers alternate between ε = 13 and ε = 1.
It is observed that the photonic gap becomes larger as the
dielectric contrast increases.
12. Wavelength in a 1D PBG
• A wave incident on a 1D band-gap material partially reflects off
each layer of the structure.
(2) The reflected waves are in phase and reinforce one another.
(3) They combine with the incident wave to produce a standing wave that
does not travel through the material.
13. Wavelength not in a 1D PBG
(1) A wavelength outside the band gap enters the 1D material.
(2) The reflected waves are out of phase and cancel out one another.
(3) The light propagates through the material only slightly attenuated.
14. 2D PBG Crystals
Left: A periodic array of dielectric cylinders in air
forming a two-dimensional band gap.
Right: Transmission spectrum of this periodic
lattice. A full 2D band gap is observed in the
wavelength range 0.22 microns to 0.38 microns.
15. Defect in a 2D PBG Crystal
Left: A defect is introduced into the system by removing
one of the cylinders. This will lead to localization of a mode
in the gap at the defect site
Right: It is seen that some transmission peak is observed in
the forbidden band. This corresponds to the defect state
which leads to spatial localization of light and has useful
applications in making a resonant cavity.
16. 2D Band Structures
A two dimensional photonic crystal with two 60o bends,
proposed by Susumu Noda’s group. These structures are
easy to fabricate but they have the problem of the photons
not being confined on the top and bottom. By introducing
point defects like making a hole larger or smaller than the
normal size, the slab can be made to act like a microcavity
and can be used for making optical add-drop filters.
17. Wavelength in a 2D PBG
(1) For a two-dimensional band gap, each unit cell of the structure
produces reflected waves.
(2) Reflected and refracted waves combine to cancel out the incoming
wave.
(3) This should happen in all possible directions for a full 2D bandgap.
18. 3D PBG crystals
3D photonic bandgaps are observed in
• Diamond structure.
• Yablonovite structure.
• Woodpile Structure.
• Inverse opal structure.
• FCC Structure.
• Square Spiral structure.
• Scaffold structure.
• Tunable Electrooptic inverse opal structure.
19. Diamond structure
The inverted diamond structure was one of the first prototype structures
predicted by Chan and Soukoulis to exhibit a large and robust 3D PBG. It
consists of an overlapping array of air spheres arranged in a diamond lattice.
This structure can be mimicked by drilling an array of criss-crossing
cylindrical holes in a bulk dielectric. The solid backbone consists of a high
refractive index material such as silicon leading to a 3D PBG as large as 27%
of the center frequency. The minimum refractive index of the backbone for
the emergence of a PBG is 2.0
20. Yablonovite Structure
This is first three dimensional photonic crystal to be made and it was named
Yablonovite after Yablonovitch who conceptualized it. A slab of material is
covered by a mask consisting of triangular array of holes. Each hole is drilled
through three times, at an angle 35.26 away from normal, and spread out 120
on the azimuth. The resulting criss-cross holes below the surface of the slab
produces a full three dimensional FCC structure. The drilling can be done by
a real drill bit for microwave work, or by reactive ion etching to create a FCC
structure at optical wavelengths. The dark shaded band on the right denotes
the totally forbidden gap
21. Woodpile Structure
The “woodpile” structure, suggested by Susumu Noda’s group, represents a three-
dimensional PBG material that lends itself to layer-by-layer fabrication.It resembles a
criss-crossed stack of wooden logs, where in each layer the logs are in parallel orientation
to each other. To fabricate one layer of the stack, a SiO2-layer is grown on a substrate
wafer, then patterned and etched. Next, the resulting trenches are filled with a high-index
material such as silicon or GaAs and the surface of the wafer is polished in order to allow
the next SiO2 layer to be grown. The logs of second nearest layers are displaced midway
between the logs of the original layer. As a consequence, 4 layers are necessary to obtain
one unit cell in the stacking direction. In a final step, the SiO2 is removed through a
selective etching process leaving behind the high-index logs.
22. Inverse Opal Structure
SEM picture of a cross-section along the cubic (110) direction of a Si
inverse opal with complete 5% PBG around 1.5 um. The structure has
been obtained through infiltration of an artificial opal with silicon
(light shaded regions) and subsequent removal of SiO2 spheres of the
opal. The air sphere diameter is 870 nanometers. Clearly visible is the
complete infiltration (diamond shaped voids between spheres) and the
effect of sintering the artificial opal prior to infiltration ( small holes
connecting adjacent spheres.)
23. FCC Structure
Computer rendering of a three dimensional photonic crystal, put forth
by Joannopoulos and his group, showing several horizontal periods
and one vertical period consisting of a FCC lattice of air holes (radius
0.293a, height 0.93a) in dielectric. This allows one to leverage the
large body of analyses, experiments, and understanding of those
simpler structures. This structure has a 21% gap for a dielectric
constant of 12.
24. Square Spiral Structure
The tetragonal lattice of square spiral posts exhibits a complete 3D PBG and
can be synthesized using glancing angle deposition (GLAD) method. This
chiral structure, suggested by John and Toader, consists of slightly
overlapping square spiral posts grown on a 2D substrate that is initially seeded
with a square lattice of growth centers. Computer controlled motion of the
substrate leads to spiraling growth of posts. A large and robust PBG emerges
between the 4th and 5th bands of photon dispersion. The inverse structure
consisting of air posts in a solid background exhibits a even larger 3D PBG.
25. Scaffolding Structure
The scaffolding structure (for it’s similarity to a
scaffolding) is a rare example of a photonic crystal that has
a very different underlying symmetry from the diamond
structure yet has a photonic band gap. The band gap is
small but definitely forbidden and this was suggested by
Joseph Haus and his colleagues.
26. Tunable 3D Inverse Opal Structure
A marriage of liquid and photonic crystals as
conceptualized by Busch and John. An inverse opal
photonic crystal structure partially infiltrated with liquid
crystal molecules. Electro-optic tuning can cause the
bandgap to wink in and out of existence. This can have
disruptive influence on our present technologies as will be
discussed later.
28. 1. Photonic Crystal Fibers
• Photonic crystal fibers (PCF) are optical fibers that employ a
microstructured arrangement of low-index material in a background
material of higher refractive index.
• The background material is undoped silica and the low index region is
typically provided by air voids running along the length of the fiber.
29. Types of PCF
PCFs come in two forms:
• High index guiding fibers based on the Modified Total
Internal Reflection (M-TIR) principle
• Low index guiding fibers based on the Photonic Band Gap
(PBG) effect.
30. M-TIR Fibers
• Tiny cylindrical holes of air separated by gaps are patterned into a fiber. The
effective cladding index (of the holes and the gaps) is lower than the core index.
• A first glance would suggest that light would escape through the gaps between
“bars” of air. But, a trick of geometry prevents this.
• The fundamental mode, being the longest wavelength, gets trapped in the core
while the higher order modes capable of squeezing in the gaps leak away
rapidly, by a process reminiscent of a kitchen sieve.
• For small enough holes, PCF remains single moded at all wavelengths and
hence given the name “endlessly single moded fiber.”
31. PBG Fibers
• PBG fibers are based on mechanisms fundamentally different from the M-TIR fibers.
• The bandgap effect can be found in nature, where bright colors that are seen in butterfly
wings are the result of naturally occurring periodic microstructures. The periodic
microstructure in the butterfly wing results in a photonic bandgap, which prevents
propagation of certain bands. This light is reflected back and seen as bright colors.
• In a PBG fiber, periodic holes act as core and an introduced defect (an extra air hole) act
as cladding. Since light cannot propagate in the cladding due to the photonic bandgap,
they get confined to the core, even if it has a lower refractive index.
• In fact, extremely low loss fibers with air or vacuum as the core can be created.
32. 2. Photonic Crystal Lasers
Architectures for 2D photonic crystal micro-lasers are shown above. (a) The Band Edge
microlaser utilizes the unique feedback and memory effects associated with a photonic band
edge and stimulated emission (arising from electron-hole recombination) from the multiple
quantum well active region occurs preferentially at the band edge. There is no defect mode
Engineered in the 2D PBG. (courtesy of S. Noda, Kyoto University). (b) Defect Mode micro
laser requires the engineering of a localized state of light within the 2D PBG. This is created
through a missing pore in the 2D photonic crystal. Stimulated emission from the multiple
quantum well active region occurs preferentially into the localized mode. (courtesy of Axel
Scherer, California Institute of Technology).
33. 3. Photonic Crystal Filters
Add-drop filter for a dense wavelength division multiplexed optical
communication system. Multiple streams of data carried at different
frequencies F1, F2, etc. (yellow) enter the optical micro-chip from an external
optical fiber and are carried through a wave guide channel (missing row of
pores). Data streams at frequency F1 (red) and F2 (green) tunnel into localized
defect modes and are routed to different destinations. The frequency of the
drop filter is defined by the defect pore diameter which is different from the
pore diameter of the background photonic crystal.
34. 4. Photonic Crystal Planar Waveguides
• Creating a bend radius of more than few millimeters is difficult in
conventional fibers because the conditions for TIR fail leading to leaky modes.
• PC waveguides operate using a different principle. A line defect is created in
the crystal which supports a mode that is in the band gap. This mode is
forbidden from propagating in the crystal because it falls in the band gap.
• When a bend needs to be created in the waveguide, a line defect of the same
shape is introduced. It is impossible for light to escape (since it cannot
propagate in the bulk crystal). The only possibility is for the mode to
propagate through the line defect (which now takes the shape of a sharp bend)
leading to lossless propagation.
35. 5. PIC on a 3D PBG Microchip
An artist’s conception of a 3D PBG woodpile structure into which a micro-laser
array and de-multiplexing (DEMUX) circuit have been integrated. (courtesy of S.
Noda, Kyoto University, Japan). These photonic integrated circuits will be prime
movers for deeper penetration of optical networking into telecommunications.
36. Future Directions
• Design of ultra compact lasers with almost zero threshold
current.
• Terahertz all-optical switch for routing data along the
internet.
• Collective switching of two-level atoms from ground to
excited state with low intensity applied laser fields leading
to all-optical transistor action.
• Ultra-small beamsplitters, Mach-Zehnder interferometers,
and functional micro-optical elements such as wavelength
add-drop filters leading to compact photonic integrated
circuits.
• Single atom memory effects for possible quantum
computer applications.
37. 1. All Optical Transistor
Micro-photonic all-optical transistor may consist of an active region buried in the
intersection of two wave-guide channels in a 3D PBG material. The two-level systems
(“atoms”) in the active region are coherently pumped and controlled by laser beams
passing through the wave guides. In addition, the 3D PBG material is chosen to
exhibit an abrupt variation in the photon density of states near the transition
frequency of the atoms. This leads to atomic “population inversion” through
coherent pumping, an effect which is forbidden in ordinary vacuum. The inversion
threshold is characterized by a narrow region of large differential optical gain (solid
curve in the inset). A second, “control laser” allows the device to pass through this
threshold region leading to strong amplification of the output signal. In ordinary
vacuum, population inversion is unattainable (dashed curve in the inset).
38. 2. All Optical Router
Artist’s depiction of an electro-actively tunable PBG routing device.
Here the PBG material has been infiltrated with an optically
anisotropic material (such as a liquid crystal) exhibiting a large electro-
optic response. When a voltage is applied to the electro optically
tunable PBG, the polarization state (yellow arrows) can be rotated,
leading to corresponding shifts in the photonic band structure. This
allows light from an optical fiber to be routed into one of several output
fibers.
39. 3. Optical Computing
With optical integrated circuits and optical transistor
technology being rendered possible by photonic crystals,
quantum computing with localized light is a very
promising technology for the future. Immense parallelism,
unprecedented speeds, superior storage density, minimal
crosstalk and interference are some of the advantages that
one gets while migrating towards optical computing.
40. 4. Optical Integrated Circuits
An artistic view of a collage
of different photonic crystal
devices going into an
integrated circuit. The
buildings are 3-D PBG
crystals. The clear buildings
with the blue balls depict a
metallo-dielectric structure.
The green "forests" show
two-dimensionally periodic
photonic crystals. The red
"roads" with holes in them
are one-dimensionally
periodic crystals.
41. Conclusion
• Light Localization occurs in carefully engineered
dielectrics.
• Photonic Band Gap formation is a synergetic interplay
between microscopic and macroscopic resonances.
• 1-D and 2-D photonic crystals are easy to fabricate.
• 3-D PBG materials: inverse diamond, woodpile, inverse
opal, Scaffold and square spiral.
• Plane, line or point defects can be introduced into photonic
crystals and used for making waveguides, microcavities or
perfect dielectric mirrors by localization of light.
• Applications – photonic crystal fibers, lasers, waveguides,
add drop filters, all-optical transistors, amplifiers, routers
photonic integrated circuits, optical computing.
42. References
1. Yablonovitch, E. Phys. Rev. Lett. 58, 2059–2062 (1987).
2. John, S. Phys. Rev. Lett. 58, 2486–2489 (1987).
3. Ho, K. M., Chan, C. T. & Soukoulis, C. M. Phys. Rev. Lett. 65, 3152–
3155 (1990).
4. Yablonovitch, E., Gmitter, T. J. & Leung, K. M. Phys. Rev. Lett.
67, 2295–2298 (1991).
43. References
5. Sozuer, H. S., Haus, J. W. & Inguva, R. Phys. Rev. B 45, 13962–13972
(1992).
6. Busch, K. & John, S. Phys. Rev. Lett. 83, 967–970 (1999).
7. Yablonovitch, E, Nature 401, 540-541 (1999)
8. John.S, Encyclopedia of Science and Technology, Academic
Press 2001.
9. http://www-tkm.physik.uni-karlsruhe.de/~kurt/encyclopedia.pdf
10. http://www.aip.org/tip/INPHFA/vol-7/iss-6/p14.pdf
11. http://www.ee.ucla.edu/faculty/profpapers/eliy_SciAm_mod.pdf
12. http://oemagazine.com/fromTheMagazine/oct01/pdf/teachinglight.pdf