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.
Photolithography is a process used in microfabrication that uses ultraviolet light to transfer geometric patterns from a photomask to a light-sensitive chemical (photoresist) on a semiconductor material like silicon. The main steps are coating the silicon wafer with photoresist using spin coating, exposing the photoresist to UV light through a photomask, developing to remove the exposed or unexposed areas of photoresist, etching to remove areas not protected by the photoresist, and stripping away the remaining photoresist. Photolithography is commonly used in processes like integrated circuit manufacturing to pattern features like transistors and logic gates.
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.
Nanotechnology enables routing information at the speed of light through photonic communication networks. Photonic band gaps and nano lasers are used to generate and amplify coherent light beams for optical switching and routing. Mirrors on the nano scale can be used as versatile routers by changing their orientation electrostatically to steer light and tightly regulate the angle. Applications include on-chip data communication, medical diagnostics, fusion energy, and laser defense. In conclusion, using nanotechnology tools like photonic band gaps, nano lasers and mirrors, information can be sent at the speed of light through photonic communication.
Thin films are layers of material ranging from fractions of a nanometer to several micrometers thick. Thin film technology involves precisely depositing individual atoms or molecules onto a substrate through various deposition techniques, including physical vapor deposition (PVD) and chemical vapor deposition (CVD). Key properties of thin films like thickness, roughness, and chemical composition must be carefully controlled. Thin films have many applications, such as in solar cells, batteries, medical device coatings, and more. Emerging areas of thin film application include biodegradable and flexible energy storage devices.
Perovskite Solar Cells
a short general overview presentation
hadi maghsoudi
device structure
crystal structure
preparation synthesis method
review papers
The document discusses etching techniques used in semiconductor fabrication. It describes wet etching and dry etching processes. Wet etching uses liquid etchants and is isotropic, while dry etching uses plasma and can be anisotropic. Dry etching is now used almost exclusively due to its ability to produce smaller feature sizes. The document outlines the mechanisms of plasma etching, including reactive neutral species and ions that perform chemical and physical etching, respectively. It also discusses factors like etch selectivity and directionality.
This document discusses perovskite solar cells. It begins with an overview of different photovoltaic technologies and efficiency charts. It then discusses the properties of perovskite materials and various device architectures for perovskite solar cells. The document outlines fabrication methods for perovskite solar cells, including potential replacements for lead and printed or roll-to-roll approaches. It concludes with a discussion of the commercialization potential and future outlook of perovskite solar cells.
The document discusses optical properties of semiconductors. It begins by introducing Maxwell's equations and how they describe light propagation in a medium with both bound and free electrons. The complex refractive index is then derived, which accounts for changes to the light's velocity and damping due to absorption. Reflectivity and transmission through a thin semiconductor slab are also examined. Key equations for the complex refractive index, reflectivity, and transmission through a thin slab are provided.
The document discusses computational modeling of perovskites for photovoltaic applications. Perovskites have shown great promise for solar cells due to their excellent optoelectronic properties. Computational modeling can provide insights into perovskite properties that are difficult to obtain experimentally. While lead-based perovskites have achieved high efficiencies, their toxicity is a concern, creating interest in developing non-toxic alternatives through computational studies and materials design. Opportunities and challenges of computational modeling for understanding perovskites and designing new materials are also examined.
This document provides an overview of plasmonics and subwavelength plasmonic waveguides and metamaterials. It begins with definitions of key plasmonic concepts like surface plasmon polaritons and localized surface plasmons. It then discusses the scientific background of plasmonics using the Drude model. Specific plasmonic materials like gold, silver, and aluminum are also examined. Different excitation methods for surface plasmon polaritons are outlined, including prism coupling and grating coupling. The document concludes by mentioning some applications and research trends in plasmonics.
Photonics involves the generation, processing, and manipulation of photons. It began with the invention of the laser in 1960. Photonics emphasizes that photons have both particle and wave properties. It is used in many applications due to light's ability to travel faster than electrons and carry more information channels. These applications include telecommunications, lighting, holography, and medicine.
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.
The document discusses photodetectors and the principles of p-n junction photodiodes. It describes the depletion region of a reverse biased p-n junction and how electron-hole pairs generated by photons are separated by the electric field. It also discusses pin photodiodes and how their intrinsic region allows for higher quantum efficiency and modulation frequencies compared to p-n junction photodiodes. Absorption coefficients of various semiconductor materials are shown as well as how direct and indirect bandgap materials differ in photon absorption.
The document discusses perovskite solar cells. It begins by defining perovskites and their crystal structure. It then discusses several important studies on perovskite solar cells that improved their efficiency over time, including studies published in 2012, 2013, 2014 and 2015 that achieved efficiencies up to 19.3%. It also reviews factors that affect the performance and stability of perovskite solar cells, such as humidity, UV light, annealing temperature, and the choice of electron transport material. In conclusion, it summarizes that perovskite solar cells have advantages over traditional silicon solar cells like easier processing, higher efficiency potential, flexibility and lower cost.
Physical vapor deposition (PVD) involves evaporating or sputtering material in vacuum chambers to form thin films or coatings on surfaces. Different PVD techniques include evaporative deposition using resistive heating or electron beams, sputter deposition using plasma or ion beams, and pulsed laser deposition. PVD is commonly used for circuit fabrication, aerospace coatings, and optics due to its ability to deposit thin, uniform coatings of various materials at high temperatures and precise thicknesses. Some advantages of PVD include producing environmentally friendly coatings without requiring post-deposition treatments, while disadvantages include high energy and vacuum requirements.
This document discusses semiconductor materials and devices. It begins by explaining electricity and electron bands in atoms. It then discusses the properties and atomic structures of conductors, insulators, and semiconductors. Semiconductors can be made to act as insulators or conductors through doping, which introduces impurity atoms. The document describes how n-type and p-type semiconductors are formed and their current flow. It concludes by explaining how a p-n junction diode is formed at the interface of p-type and n-type semiconductors and its current-voltage characteristics.
Extreme ultraviolet lithography (EUVL) is an advanced lithography technique needed to continue following Moore's Law and make more powerful microprocessors. EUVL uses light with a wavelength of 13.5nm, which is much shorter than visible light, allowing for smaller feature sizes. The EUVL process involves projecting a mask pattern through a series of reflective mirrors onto a photoresist-coated wafer under vacuum. Key aspects of EUVL include the use of reflective masks and all-reflective optical systems since materials absorb 13.5nm light. EUVL promises increased processor speeds and storage capacity but faces challenges like low mirror reflectivity and contamination control required for the vacuum environment.
This document provides an introduction to the field of nanophotonics. It defines nanophotonics as the science and engineering of light-matter interactions that take place on wavelength and subwavelength scales. Examples of nanophotonics in nature are discussed. The foundations of nanophotonics are explored, including similarities between the propagation of photons and electrons. Computational methods for modeling nanophotonic structures like finite difference time domain are also summarized. The effects of quantum confinement on the optical properties of nanostructures are described.
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.
The document discusses a study on the realization and application of fiber optics for vibration measurement in electrical switchgear, outlining the objectives and overview of the project which includes understanding fiber optic principles and applications, studying vibration sensors and their use, and analyzing how fiber optics can benefit vibration measurement in switchgear. It provides background on fiber optics, lasers, detectors, and sensors before reviewing vibration measurement and analyzing the advantages and limitations of using fiber optics for this application in electrical equipment.
The document summarizes recent developments in optical and photonic technology at Zhejiang University's Department of Optical Engineering. It discusses research on micro- and nano-fibers, photonic crystals, optical thin film devices, and their applications. The department has grown to become a leading institution in China for optical engineering education and research, with over 98 faculty/staff members and extensive funding for projects.
The document discusses photonic crystals and photonic crystal lasers. Photonic crystals are nanostructures that affect photon propagation through periodic dielectric materials, similarly to how semiconductor crystals affect electron motion. Photonic crystals allow control over photon flow and material properties. Photonic crystal lasers have been designed with quantum dots in the active region and patterned waveguides. They offer ultralow thresholds, high quality factors, and flexibility. However, their output power is currently on the microwatt scale. Potential applications include single-photon sources for quantum information and low-power spectroscopy sources.
The document summarizes key characteristics and applications of lasers. It describes the properties of coherence, high intensity, high directionality, and monochromaticity that distinguish lasers from other light sources. It also discusses the processes of induced absorption, spontaneous emission, and stimulated emission that enable laser action. Common laser systems like Nd:YAG are described along with their components and working. Finally, the document outlines several industrial, medical, military, scientific, and engineering applications of lasers such as welding, cutting, surgery, communication, and chemical reactions.
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
Optical Fiber Basic Concept Which May Help You To Understand More Easily. The Slide Is Specially For Engineering Background. Anyone can get easily understand by studying this material. Thank you.
Photonic crystals can manipulate light signals and guide them through solid structures. They are periodic lattice structures that can create photonic band gaps to control the paths of particular light frequencies. Surface wave guides use nanostructured metal surfaces to direct photon beams along paths between regular arrays, with surface plasmons guiding the light. Photonic crystals have applications in fiber optic communication, single mode LEDs, lasers, optical devices, fast electronics, and medical therapy. They represent the future of semiconductors and will have wide cross-field applications due to their ability to transport energy as photons rather than electrons.
The document discusses the history and development of electron microscopes. It begins by explaining Ernst Ruska's 1931 sketch of the first electron microscope. Magnetic lenses are used instead of glass lenses due to strong aberrations. This allows for higher resolutions around 2-3 Angstroms at 100keV and below 1 Angstrom at 1000keV. Later improvements include field emission guns which produce smaller, more coherent electron beams. Condenser lenses are used to focus the beam while the objective lens limits resolution. Intermediate lenses provide further magnification. Lens aberrations like spherical aberration are also discussed.
Traineeship Melbourne University - Michael BeljaarsMichael Beljaars
This document summarizes a student's research project investigating the use of nano-apertures to improve the spatial resolution of ion beam lithography. The student had difficulty milling nano-apertures in atomic force microscope cantilevers using a focussed ion beam, but was eventually able to use one successfully to mask a 1.5 MeV helium ion beam. The document also describes the background and motivation for the research, including limitations of current ion beam lithography techniques and how nano-aperture masking could help overcome these limitations to enable the creation of photonic crystals.
This document discusses the study of optical characteristics of nano-antennas. It begins by introducing metallic optical nano-antennas and how their properties depend on geometry and materials. Nano-antennas have potential applications in nanophotonics by confining electromagnetic waves at metal-dielectric interfaces at scales smaller than the light wavelength. Different types of nano-antennas are presented, including dipole antennas and spiral antennas. The document discusses several key optical properties of nano-antennas including their polarization sensitivity, directional sensitivity, and applications in areas like plasmonic sensing and biochemical detection. In conclusions, nano-antennas represent an area of light detection where both technological and fundamental problems need to be addressed through further research.
This document is a term paper on photonic crystal fiber submitted by Chahat Gupta to their professor Dr. Maninder Lal Singh. It includes an introduction to optical fibers, photonic crystals, and photonic crystal fibers. It discusses two guiding mechanisms for photonic crystal fibers - modified total internal reflection and photonic bandgap guidance. It also outlines some applications of photonic crystal fibers such as being endlessly single mode, enabling zero dispersion at desired wavelengths, and using in sensing applications with long period fiber gratings.
This document discusses optical fibers, including their history, structure, working principle, classification, applications, advantages, and disadvantages. Optical fibers guide light and are made of glass or plastic. They were first demonstrated in the 1840s and used for image transmission in the 1920s. An optical fiber has a core and cladding, with the core having a higher refractive index to allow total internal reflection of light. Optical fibers are classified by mode and refractive index profile. They transmit data with high bandwidth and security over long distances at low power. However, initial installation costs are high. Optical fibers now have applications in telecommunications, broadband, medicine, and more.
The document discusses nantennas, which are nanoscopic antennas that can convert solar radiation into electricity. Nantennas address many limitations of traditional photovoltaic cells. They work by absorbing electromagnetic waves from solar radiation and thermal earth radiation. This induces an alternating current in the nantenna, which is then rectified into direct current using a diode. Nantennas show promise for applications like self-charging batteries and could be mass produced inexpensively using roll-to-roll manufacturing. Future research aims to improve rectifier efficiency and upscale the technology for widespread use.
A brief overview of the processes involved in nanolithography & nanopatterning. It mainly discusses the steps, mechanism & instrumentation of the electron beam lithography in detail. It also gives a small view on other technologies as well.
Nanoelectronics refers to using nanotechnology in electronic components to develop nanomachines by scientific methods at the atomic scale. The goal is to reduce the size, risk, and surface area of materials and molecules. Moore's Law predicted that the number of transistors on integrated circuits would double every two years. The semiconductor roadmap assesses requirements to continue Moore's Law by advancing integrated circuit performance and removing roadblocks. Nanolithography techniques like optical lithography, x-ray lithography, and immersion lithography are used in the top-down approach to fabricate leading-edge semiconductors and NEMS through multiple lithographic cycles. The bottom-up approach involves molecular components self-assembling into larger structures from
Nanomaterials are characterized by at least one dimension in the nanometer range. Their properties differ from bulk materials due to two main factors: increased surface area and quantum effects. These factors can enhance properties such as reactivity, strength, and electrical characteristics. Metamaterials are artificial materials engineered to have properties not found in nature. They derive their properties from their structure rather than composition. Metamaterials can manipulate electromagnetic waves in ways not possible with conventional materials, such as achieving a negative index of refraction. Potential applications include invisibility cloaks, improved telecommunications and solar cells.
The document discusses various building materials including bricks, cement, and aggregates. Bricks are made from clay that is heated to high temperatures, resulting in a strong and stable compound. Cement is made through a chemical process involving calcium, silicon, aluminum and iron compounds. There are various types of cement suited for different conditions. Aggregates include natural materials like sand and gravel as well as manufactured materials. Their properties influence the properties of concrete.
1) The document discusses modeling of various material parameters such as dielectric constant, bandgap, electron affinity, effective masses, and mobility as functions of composition in semiconductor alloys. It also discusses modeling of fields, recombination, carrier transport, and excess carriers in semiconductor heterojunctions.
2) Equations are provided for modeling parameters like cutoff frequency and capacitance-voltage characteristics of semiconductor diodes and transistors.
3) The relationships between material grading and device characteristics such as current-voltage behavior in diodes are examined.
Honeycomb carbon materials use a sandwich construction that provides great versatility through a variety of core and facing material combinations. Key criteria for selecting core, facing, and adhesive materials include structural considerations like strength and stiffness, economic factors, and environmental conditions such as temperature, acoustics, and moisture. The directional properties of honeycomb cores and some facings require orienting the materials to take best advantage of their mechanical attributes.
The document summarizes key components and functions of eukaryotic cells. It describes the nucleus containing nuclear envelope, nucleolus, chromatin and nucleoplasm. It also describes other organelles like mitochondria which produces energy, chloroplasts which facilitate photosynthesis, ribosomes which perform protein synthesis, endoplasmic reticulum which transports chemicals, lysosomes which break down molecules, peroxisomes which oxidize molecules, and the Golgi apparatus which modifies and secretes chemicals. It compares prokaryotic and eukaryotic flagella and discusses passive and active transport and endocytosis and exocytosis.
The document summarizes key components and structures of bacterial cells. It describes the cytoplasm as the site of cell functions and containing structures like ribosomes and plasmids. The cell envelope encases the cytoplasm and contains peptidoglycan and lipopolysaccharides. The nucleoid region contains bacterial DNA that is not enclosed in a membrane-bound nucleus. Other structures discussed include flagella, pili, inclusion bodies, and endospores.
Conducting polymers were discovered in the late 1970s and represent an important class of organic polymers that can conduct electricity. They become conductive through a process called doping, where their polymer chains take on charges. This allows for charge carriers called polarons and bipolarons to form, making the material conductive. Conducting polymers have advantages over traditional conductors including light weight, flexibility, and potential applications in areas like sensors, batteries, and displays. However, issues remain around their reproducibility, stability, processing difficulties, and high costs.
Nanotechnology involves manipulating matter at the nanoscale to create new materials and devices. At the nanoscale of 1-100 nanometers, materials exhibit novel optical, mechanical, and electrical properties. Nanomedicine uses nanotechnology for drug delivery, diagnostics, and tissue engineering. Some benefits of nanomedicine include more targeted drug delivery to reduce side effects, multifunctional nanoparticles that can deliver drugs, target cells, and enable imaging, and potential uses like artificial blood cells. Challenges include interactions with the immune system, tracking nanoparticles in the body, and developing safe and effective medical nanorobots.
The document discusses deadlock in computer systems. It defines deadlock and lists necessary conditions for deadlock including mutual exclusion, hold and wait, no preemption, and circular wait. It also discusses strategies for dealing with deadlock such as detection, recovery, and prevention/avoidance. The resource allocation graph (RAG) model is introduced as a way to represent system states and detect deadlock. Algorithms like Banker's algorithm aim to avoid deadlock by ensuring safe allocation of resources.
Mid America Trucking Show Exhibitor List 2024 - Exhibitors DataExhibitors Data
Mid America Trucking Show 2024 offers industry professionals an ideal platform to explore the latest equipment and technology through engaging and interactive exhibit displays. Reach out to your target audience with our Mid America Trucking Show Exhibitor List 2024!
2024's Top Chief Revenue Officers to Follow.pdfTHECIOWORLD
He exemplifies this approach by his unshakable commitment to generating results and his relentless drive, as evidenced by his over 15 years of experience in the industry. As an accomplished professional in the diversified industry of telecommunications, his story illustrates the power of enthusiasm and tenacity to propel success.
Mobile Application pentesting blog.docx.pdffortbridge4
Mobile Application Pentesting, also known as penetration testing. It is an important method for detecting and fixing security weaknesses in mobile applications. Here, cyber security specialists pretend that they are attackers while conducting tests in order to discover some possible flaws in advance of attackers taking advantage of them.
Cracking the Corporate Social Responsibilty Code.pptxWorkforce Group
Corporate Social Responsibility (CSR) has evolved from a nice-to-have to a strategic imperative for businesses aiming for long-term success. Understanding and implementing effective CSR strategies can transform your organisation’s relationship with stakeholders, enhance its reputation, and contribute to its financial performance.
Implementing effective CSR strategies involves more than just philanthropic efforts; it requires a comprehensive understanding of your company's role in the community and the environment.
So, how do you approach Corporate Social Responsibility (CSR)?
In this deck you will learn the underlying concept of an effective Corporate Social Responsibility (CSR) strategy.
You’ll also learn
•The various types of CSR initiatives that exists
•Popular CSR strategies deployed by socially responsible organisations
•Tips for creating a socially responsible company.
The standard operating procedure aims to align all the Digital Marketing Efforts into a single channel and help to measure the effectiveness of each department.
This SOP applies to all digital marketing activities including
• Social Media Marketing (SMM)
• Search Engine Marketing (SEM)
• Digital Ads
• Web Development
• SEO
• Email Marketing
• SMS Marketing
• Community Marketing (Whatsapp/ Viber etc.)
• Paid Marketing
• Native Marketing
• Analytics Tools
The report provides detailed insights into project economics, including capital investments, project funding, operating expenses, income and expenditure projections, fixed costs vs. variable costs, direct and indirect costs, expected ROI and net present value (NPV), profit and loss account, financial analysis, etc.
Why is Structural Engineering Critical in Disaster Preparedness and Resilienc...grouphirani24
Structural engineering forms the bedrock of resilient communities, especially in the face of natural disasters and unforeseen crises. At Hirani Group, our commitment to excellence in structural engineering services is rooted in the belief that robust infrastructure is fundamental to disaster preparedness and long-term resilience. Our team of dedicated professionals specializes in both residential and commercial structural engineering services, ensuring that every project is fortified against potential hazards and stands the test of time. In today’s unpredictable world, the role of structural engineering in disaster preparedness cannot be overstated.
Solution manual for canadian income taxation 20222023 25th edition by william...stanslausnzuki569
Solution manual for canadian income taxation 20222023 25th edition by william buckwold joan kitunen matthew roman.pdf
Solution manual for canadian income taxation 20222023 25th edition by william buckwold joan kitunen matthew roman.pdf
2. Photonics "Photonics" comes from "photon" which is the smallest unit of light just as an electron is the smallest unit of electricity. "Photonics is the generation, process and manipulation of photon to achieve a certain function.
3. Why Do We Need Photonics instead of Electronics? An “All - Pervasive” Technology 1) Uninhibited light travels thousands of times faster than electrons in computer chips. Optical computers will compute thousand of times faster than any electronic computer can ever achieve due to the physical limitation differences between light and electricity. Can pack more wavelengths (that is information channels) into a optical fibre so that the transmission bandwidth is increased than conventional copper wires. Light encounters no electromagnetic interference than that of electron in copper wires.
5. SO WHAT ARE PHOTONIC CRYSTALS ? Photonic crystals are a new type of materials displaying unusual and attractive properties in the interaction with light Due to periodic modulation of the refractive index of a material, it is possible to create tailored dispersion relations and stop bands of light propagating through the material.
7. Features of a photonic crystal • Made of low-loss periodic dielectric medium • Optical analog to the electrical semiconductors • Able to localize light in specified areas by preventing light from propagating in certain directions – optical bandgap.
8. In 2D photonic crystal structures it is possible to confine light within a cavity . Photonic band gaps appear in the plane of periodicity and in 2D we can achieve linear localization . By introducing a defect, i.e. removing one column, we may obtain a peak in the density of states localized in the photonic band gap – similar to semiconductors. The defect mode cannot penetrate the crystal in the xy-plane because of the band gap but extends in the z-direction
9. Photonic Crystals The Principle with photonic band gaps: “ optical insulators ” “ magical oven mitts” for holding and controlling light can trap light in cavities and waveguides (“wires”)
10. Photonic Crystals The Principle Periodic arrangement of ions on a lattice gives rise to energy band structure in semiconductors ,which control motion of charge carriers through crystal. Similarly ,in photonic crystals ,the periodic arrangement of refractive index variation ,controls how photons are able to move through crystal.
12. Photonic band gap crystals -- a history Idea of " photonic band gap structure " was first advanced in 1987 by Eli Yablonovitch , now a professor at the University of California at Los Angeles. In 1990, he built the first photonic crystal , baseball-sized to channel microwaves useful in antennae applications
13. Photonic Band Gaps Photons with a certain range of wavelengths do not have an energy state to occupy in a structure These photons are forbidden in the structure and cannot propagate Analogous to forbidden energy gaps in semiconductors
14. Carefully engineered line defects could act as waveguides connecting photonic devices in all-optical microchips, and infiltration of the photonic material with suitable liquid crystals might produce photonic bandgap structures (and hence light-flow patterns) fully tunable by an externally applied voltage
21. Applications Of Photonic Crystals Perfect mirror :There are materials that reflect the frequency range of interest, with essentialy no loss at all. Such materials are widely available all the way from the ultraviolet regime to the microwave. Nonlinear effects : Using non-linear properties of materials for construction of photonic crystal lattices open new possibilities for molding the flow of light. In this case the dielectric constant is additionally depend on intensity of incident electromagnetic radiation and any non-linear optics phenomena can appeared.
22. Applications Of Photonic Crystals Photonic integrated circuits based on photonic crystals. The key driving force of this research is the miniaturisation and increase of the functionality of photonic circuits. The application of photonic crystal technology allows us to design waveguides, couplers, and routers on a much smaller scale than previously possible, thus allowing the design of high-density integrated circuits Applications of this work are in telecommunications, e.g. for devices that manage high-speed, high volume data (e.g. internet) traffic. A part of Photonic integrated circuit
23. Applications Of Photonic Crystals Novel Semiconductor lasers and light emitters : Efficient light sources (e.g. for lighting ,displays) and novel types of optical sensors ,e.g. for biomedical applications.
24. Imaging by a Flat Slab of Photonic crystal Source 2. 25 cm from PC Image 2. 75 cm Subwavelength image 2D flat lens F= 9.3 GHz Wavelength=3.22 cm Scale Intensity: -20 dB to -40 dB X-Y: 37.5 X 30 cm 2
25. Self organized Nano Photonic Crystal Negative refraction in Photonic Crystal 3D IMAGING IN REAL SPACE Semiconductor substrate
26. Flat lens n = -1 d d = u + v v u object image Normal lens: Resolution cannot be greater than Flat lens : no limitation on the resolution Image resolution Normal lens
27. E H H E PIM PIM Turning light on its Head Positive Refraction PIM NIM E H E H Negative Refraction
28. Conventional Optical lens Photonic Crystal lens Advantages of Photonic Crystal lens Optical axis Limited aperture cannot NO Optical axis No limitation on aperture size Subwavelength imaging (evanescent wave amplification) PC : Scalability to sub-micron dimensions -> applications at optical frequencies
29. Applications Of Photonic Crystals Photonic transistor A transistor is a switch that is turned on and off by signals from other switches. They perform logic, store information and are the work horses of digital computing. Photonic transistors use light to perform the switching functions that are performed by electronic transistors in conventional computers.
30. Applications Of Photonic Crystals Replacing conventional optical fibres The Glass Ceiling : Limits of Silica Loss : amplifiers every 50–100km … cannot use “exotic” wavelengths like 10.6µm Nonlinearities : after ~100km, cause dispersion, crosstalk, power limits (limited by mode area ~ single-mode, bending loss) also cannot be made (very) large for compact nonlinear devices Radical modifications to dispersion, polarization effects …tunability is limited Long Distances High Bit-Rates Dense Wavelength Multiplexing (DWDM) Compact Devices
31. Future Applications Highly efficient photonic crystal lasers High resolution spectral filters Photonic crystal diodes and transistors High efficiency light bulbs Optical computers Telecommunication & computer networks Photonic clothes and candy bars??
32. Fabrication Of Photonic Crystals An example of a two-dimensional photonic crystal. The distance between the 200 nm wide pillars is about 500 nm and the pillars are 1500 nm long.
33. Fabrication Of Photonic Crystals Waveguide bend in a two-dimensional array of rods. The waveguide bend is defined by removing a row rods.
34. Fabrication Of Photonic Crystals Microfabrication : By layer by layer lithography. Colloidal self-assembly.
35. Fabrication Of Photonic Crystals The Biological Option Layer-by-Layer Lithography • Fabrication of 2d patterns in Si or GaAs is very advanced (think: Pentium IV, 50 million transistors) So, make 3d structure one layer at a time
38. Lithography Basic sequence The surface to be patterned is: spin-coated with photoresist the photoresist is dehydrated in an oven ( photo resist : light-sensitive organic polymer) The photoresist is exposed to ultra violet light: For a positive photoresist exposed areas become soluble and non exposed areas remain hard The soluble photoresist is chemically removed (development). The patterned photoresist will now serve as an etching mask for the SiO 2
39.
40. The SiO2 is etched away leaving the substrate exposed: the patterned resist is used as the etching mask Ion Implantation : the substrate is subjected to highly energized donor or acceptor atoms The atoms impinge on the surface and travel below it The patterned silicon SiO2 serves as an implantation mask The doping is further driven into the bulk by a thermal cycle Lithography (contd.) The lithographic sequence is repeated for each physical layer
41. 2µm Lithography at its best = 780nm resolution = 150nm 7µm (3 hours to make)
42. Lithography at its best 2µm ( 300nm diameter coils, suspended in ethanol, viscosity-damped )
44. Mass Production by Holographic Lithography absorptive material Four beams make 3d-periodic interference pattern (1.4µm) k -vector differences give reciprocal lattice vectors ( i.e. periodicity) beam polarizations + amplitudes (8 parameters) give unit cell
46. Mass Production :Colloids microspheres (diameter < 1µm) silica (SiO 2 ) sediment by gravity into close-packed fcc lattice ! (evaporate)
47. Inverse Opals fcc solid spheres do not have a gap… … but fcc spherical holes in Si do have a gap [ figs courtesy D. Norris, UMN ] Infiltration sub-micron colloidal spheres Template (synthetic opal) 3D Remove Template “ Inverted Opal”
48. In Order To Form a More Perfect Crystal… meniscus silica 250nm Capillary forces during drying cause assembly in the meniscus Extremely flat, large-area opals of controllable thickness Heat Source 80C 65C 1 micron silica spheres in ethanol evaporate solvent
51. Manufacturing Photonic Materials: The Biological Option With the help of DNA very complex structures can be manufactured . But even then present technology cannot produce crystals producing a more spectacular effect than in the butterfly’s wings. The Mitoura Grynea butterfly Electron micrograph of a broken scale taken from mitoura grynea revealing a periodic array of holes responsible for the colour
52. Recent Developments (taking it a step ahead) MIT researchers reported in the October 9,1998 issue of Science that they have proven through experiments their long-standing theory on a new way to manipulate light waves. Their photonic crystals do what no other waveguide has managed to do: guide light around a 90-degree turn without losing even an iota of efficiency. The picture depicts waveguide bend exhibiting 100% transmission
53. Recent Developments (taking it a step ahead) MIT researchers reported in the November 27,1998 issue of Science that they have made an important new advance in an age-old device -- the mirror. The new kind of mirror developed at MIT can reflect light from all angles and polarizations , just like metallic mirrors, but also can be as low-loss as dielectric mirrors. The "perfect mirror" as quoted by the researchers, is trapping light for longer than ever before possible. This would open up a myriad of technological and research possibilities.
54. Recent Developments (taking it a step ahead) Jan. 10,2003 --MIT researchers have created a low-loss optical fiber that may lead to advances in medicine, manufacturing, sensor technology and telecommunications.
55. Recent Developments (taking it a step ahead) Photonic chips go 3D The dream of building computer chips that use light signals rather than electricity has entered the realm of serious research in recent years with the advent of photonic crystal , a material that blocks and channels light within extremely small spaces. Research teams from the Massachusetts Institute of Technology and from Kyoto University have made devices that meet all three challenges. This image shows the microscopic structure of a three-dimensional photonic crystal that is capable of channeling and emitting light in the visible and telecommunications ranges .