Measurement of the Refractive Index and Dispersion of Optical Glass For
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Thermal Shock
TEACHER INSTRUCTIONS Thermal Shock Objective: To illustrate thermal expansion and thermal shock. Background Information: In physics, thermal expansion is the tendency of matter to increase in volume or pressure when heated. For liquids and solids, the amount of expansion will normally vary depending on the material’s coefficient of thermal expansion. When materials contract, tensile forces are created. When things expand, compressive forces are created. Thermal shock is the name given to cracking as a result of rapid temperature change. From the laboratory standpoint, there are three main types of glass used today: borosilicate, quartz, and soda lime or flint glass. Borosilicate glass is made to withstand thermal shock better than most other glass through a combination of reduced expansion coefficient and greater strength, though fused quartz outperforms it in both respects. Some glass-ceramic materials include a controlled proportion of material with a negative expansion coefficient, so that the overall coefficient can be reduced to almost exactly zero over a reasonably wide range of temperatures. Improving the shock resistance of glass and ceramics can be achieved by improving the strength of the materials or by reducing its tendency to uneven expansion. One example of success in this area is Pyrex, the brand name that is well known to most consumers as cookware, but which is also used to manufacture laboratory glassware. Pyrex traditionally is made with a borosilicate glass with the addition of boron, which prevents shock by reducing the tendency of glass to expand. Demo description: Three different types of glass rods will be heated so that students can observe the amount of thermal shock that occurs. -
Simple Method for Measuring the Zero-Dispersion Wavelength in Optical Fibers Maxime Droques, Benoit Barviau, Alexandre Kudlinski, Géraud Bouwmans and Arnaud Mussot
Simple Method for Measuring the Zero-Dispersion Wavelength in Optical Fibers Maxime Droques, Benoit Barviau, Alexandre Kudlinski, Géraud Bouwmans and Arnaud Mussot Abstract— We propose a very simple method for measuring the zero-dispersion wavelength of an optical fiber as well as the ratio between the third- and fourth-order dispersion terms. The method is based on the four wave mixing process when pumping the fiber in the normal dispersion region, and only requires the measurement of two spectra, provided that a source tunable near the zero- dispersion wavelength is available. We provide an experimental demonstration of the method in a photonic crystal fiber and we show that the measured zero-dispersion wavelength is in good agreement with a low-coherence interferometry measurement. Index Terms— Photonic crystal fiber, four-wave-mixing, chromatic dispersion, zero-dispersion wavelength. I. INTRODUCTION Group velocity dispersion (GVD) is one of the key characteristics of optical fibers. It is thus important to be able to accurately measure this parameter. The techniques developed to reach this goal can be divided into two main categories: the ones based on linear processes, such as time-of-flight, phase-shift or interferometric measurements [1-4]; and the ones based on nonlinear effects, such as four wave mixing (FWM), mainly [5-8]. The main advantage of these last ones is that the GVD measurement can be made in fiber samples ranging from a few meters up to hundred of meters long, while linear techniques are restricted to either very short samples (in the meter range) or to very long ones (in the kilometer range). -
Tauc-Lorentz Dispersion Formula
TN11 Tauc-Lorentz Dispersion Formula Spectroscopic ellipsometry (SE) is a technique based on the measurement of the relative phase change of re- flected and polarized light in order to characterize thin film optical functions and other properties. The meas- ured SE data are used to describe a model where layers refer to given materials. The model uses mathematical relations called dispersion formulae that help to evaluate the material’s optical properties by adjusting specific fit parameters. This technical note deals with Tauc-Lorentz dispersion formula. Theoretical model The real part εr,TL of the dielectric function is derived from the expression of εi using the Kramers-Kronig integration. Jellison and Modine developed this model (1996) using Then, it comes the following expression for εi: the Tauc joint density of states and the Lorentz oscillator. The complex dielectric function is : 2 ∞ ξ ⋅ε ()ξ ε ()E = ε ()∞ + ⋅ P ⋅ i dξ ()5 ~ε =ε + i ⋅ε =ε + i ⋅(ε × ε ) (1) r r π ∫ ξ 2 − E 2 TL r,TL i,TL r,TL i,T i, L Eg Here the imaginary part εi,TL of the dielectric function is where P is the Cauchy principal value containing the resi- given by the product of imaginary part of Tauc’s (1966) dues of the integral at poles located on lower half of the dielectric εi,T function with Lorentz one εi,L. In the approx- complex plane and along the real axis. imation of parabolic bands, Tauc’s dielectric function de- According to Jellison and Modine (Ref. 1), the derivation scribes inter-band transitions above the band edge as : of the previous integral yields : E − E 2 ⎛ g ⎞ 2 2 εi,T ()E > Eg = AT ⋅⎜ ⎟ ()2 A⋅C ⋅a ⎡ E + E + α ⋅ E ⎤ ⎜ E ⎟ ln 0 g g ⎝ ⎠ εr,TL ()E = ε∞ + 4 ⋅ln⎢ 2 2 ⎥ where : 2⋅π ⋅ζ ⋅α ⋅ E0 ⎣⎢ E0 + Eg − α ⋅ Eg ⎦⎥ -A is the Tauc coefficient T A a ⎡ ⎛ 2⋅ E + α ⎞ - E is the photon energy − ⋅ a tan ⋅ π − arctan⎜ g ⎟ + 4 ⎢ ⎜ ⎟ K -Eg is the optical band gap π ζ ⋅ E0 ⎣ ⎝ C ⎠ The imaginary part of Tauc’s dielectric function gives the ⎛ α − 2⋅ E ⎞⎤ response of the material caused by inter-band mecha- g + arctan⎜ ⎟⎥ nisms only : thus εi, T (E ≤ Eg) = 0. -
The American Ceramic Society 25Th International Congress On
The American Ceramic Society 25th International Congress on Glass (ICG 2019) ABSTRACT BOOK June 9–14, 2019 Boston, Massachusetts USA Introduction This volume contains abstracts for over 900 presentations during the 2019 Conference on International Commission on Glass Meeting (ICG 2019) in Boston, Massachusetts. The abstracts are reproduced as submitted by authors, a format that provides for longer, more detailed descriptions of papers. The American Ceramic Society accepts no responsibility for the content or quality of the abstract content. Abstracts are arranged by day, then by symposium and session title. An Author Index appears at the back of this book. The Meeting Guide contains locations of sessions with times, titles and authors of papers, but not presentation abstracts. How to Use the Abstract Book Refer to the Table of Contents to determine page numbers on which specific session abstracts begin. At the beginning of each session are headings that list session title, location and session chair. Starting times for presentations and paper numbers precede each paper title. The Author Index lists each author and the page number on which their abstract can be found. Copyright © 2019 The American Ceramic Society (www.ceramics.org). All rights reserved. MEETING REGULATIONS The American Ceramic Society is a nonprofit scientific organization that facilitates whether in print, electronic or other media, including The American Ceramic Society’s the exchange of knowledge meetings and publication of papers for future reference. website. By participating in the conference, you grant The American Ceramic Society The Society owns and retains full right to control its publications and its meetings. -
Negative Refractive Index in Artificial Metamaterials
1 Negative Refractive Index in Artificial Metamaterials A. N. Grigorenko Department of Physics and Astronomy, University of Manchester, Manchester, M13 9PL, UK We discuss optical constants in artificial metamaterials showing negative magnetic permeability and electric permittivity and suggest a simple formula for the refractive index of a general optical medium. Using effective field theory, we calculate effective permeability and the refractive index of nanofabricated media composed of pairs of identical gold nano-pillars with magnetic response in the visible spectrum. PACS: 73.20.Mf, 41.20.Jb, 42.70.Qs 2 The refractive index of an optical medium, n, can be found from the relation n2 = εμ , where ε is medium’s electric permittivity and μ is magnetic permeability.1 There are two branches of the square root producing n of different signs, but only one of these branches is actually permitted by causality.2 It was conventionally assumed that this branch coincides with the principal square root n = εμ .1,3 However, in 1968 Veselago4 suggested that there are materials in which the causal refractive index may be given by another branch of the root n =− εμ . These materials, referred to as left- handed (LHM) or negative index materials, possess unique electromagnetic properties and promise novel optical devices, including a perfect lens.4-6 The interest in LHM moved from theory to practice and attracted a great deal of attention after the first experimental realization of LHM by Smith et al.7, which was based on artificial metallic structures -
Measurement of Verdet Constant in Diamagnetic Glass Using Faraday Effect
18Kasetsart J. (Nat. Sci.) 40 : 18 - 23 (2006) Kasetsart J. (Nat. Sci.) 40(5) Measurement of Verdet Constant in Diamagnetic Glass Using Faraday Effect Kheamrutai Thamaphat, Piyarat Bharmanee and Pichet Limsuwan ABSTRACT Many materials exhibit what is called circular dichroism when placed in an external magnetic field. An equivalent statement would be that the two circular polarizations have different refractive indices in the presence of the field. For linearly polarized light, the plane of polarization rotates as it propagates through the material, a phenomenon that is called the Faraday effect. The angle of rotation is proportional to the product of magnetic field, path length through the sample and a constant known as the Verdet constant. The objectives of this experiment are to measure the Verdet constant for a sample of dense flint glass using Faraday effect and to compare its value to a theoretical calculated value. The experimental values for wavelength of 505 and 525 nm are V = 33.1 and 28.4 rad/T m, respectively. While the theoretical calculated values for wavelength of 505 and 525 nm are V = 33.6 and 30.4 rad/T m, respectively. Key words: verdet constant, diamagnetic glass, faraday effect INTRODUCTION right- and left-handed circularly polarized light are different. This effect manifests itself in a rotation Many important applications of polarized of the plane of polarization of linearly polarized light involve materials that display optical activity. light. This observable fact is called magnetooptic A material is said to be optically active if it rotates effect. the plane of polarization of any light transmitted Magnetooptic effects are those effects in through the material. -
Technical Glasses
Technical Glasses Physical and Technical Properties 2 SCHOTT is an international technology group with 130 years of ex perience in the areas of specialty glasses and materials and advanced technologies. With our highquality products and intelligent solutions, we contribute to our customers’ success and make SCHOTT part of everyone’s life. For 130 years, SCHOTT has been shaping the future of glass technol ogy. The Otto Schott Research Center in Mainz is one of the world’s leading glass research institutions. With our development center in Duryea, Pennsylvania (USA), and technical support centers in Asia, North America and Europe, we are present in close proximity to our customers around the globe. 3 Foreword Apart from its application in optics, glass as a technical ma SCHOTT Technical Glasses offers pertinent information in terial has exerted a formative influence on the development concise form. It contains general information for the deter of important technological fields such as chemistry, pharma mination and evaluation of important glass properties and ceutics, automotive, optics, optoelectronics and information also informs about specific chemical and physical character technology. Traditional areas of technical application for istics and possible applications of the commercial technical glass, such as laboratory apparatuses, flat panel displays and glasses produced by SCHOTT. With this brochure, we hope light sources with their various requirements on chemical to assist scientists, engineers, and designers in making the physical properties, have led to the development of a great appropriate choice and make optimum use of SCHOTT variety of special glass types. Through new fields of appli products. cation, particularly in optoelectronics, this variety of glass types and their modes of application have been continually Users should keep in mind that the curves or sets of curves enhanced, and new forming processes have been devel shown in the diagrams are not based on precision measure oped. -
Section 5: Optical Amplifiers
SECTION 5: OPTICAL AMPLIFIERS 1 OPTICAL AMPLIFIERS S In order to transmit signals over long distances (>100 km) it is necessary to compensate for attenuation losses within the fiber. S Initially this was accomplished with an optoelectronic module consisting of an optical receiver, a regeneration and equalization system, and an optical transmitter to send the data. S Although functional this arrangement is limited by the optical to electrical and electrical to optical conversions. Fiber Fiber OE OE Rx Tx Electronic Amp Optical Equalization Signal Optical Regeneration Out Signal In S Several types of optical amplifiers have since been demonstrated to replace the OE – electronic regeneration systems. S These systems eliminate the need for E-O and O-E conversions. S This is one of the main reasons for the success of today’s optical communications systems. 2 OPTICAL AMPLIFIERS The general form of an optical amplifier: PUMP Power Amplified Weak Fiber Signal Signal Fiber Optical AMP Medium Optical Signal Optical Out Signal In Some types of OAs that have been demonstrated include: S Semiconductor optical amplifiers (SOAs) S Fiber Raman and Brillouin amplifiers S Rare earth doped fiber amplifiers (erbium – EDFA 1500 nm, praseodymium – PDFA 1300 nm) The most practical optical amplifiers to date include the SOA and EDFA types. New pumping methods and materials are also improving the performance of Raman amplifiers. 3 Characteristics of SOA types: S Polarization dependent – require polarization maintaining fiber S Relatively high gain ~20 dB S Output saturation power 5-10 dBm S Large BW S Can operate at 800, 1300, and 1500 nm wavelength regions. -
Examples of Translucent Objects
Examples Of Translucent Objects Chancier and ecclesiological Chan never nebulise his heroes! Afternoon and affirmable Garvin often arterialised some yokes glisteringly or nuggets jealously. Rationalist and papist Erastus attunes while frogged Robb descant her mercs anaerobically and misclassifies moistly. You wish them, a whole and water droplets in translucent materials, like to be directed to translucent, and translucency is pumpkin seed oil. Learn more energy when the error you found that is diffused and table into light? Light can see more light through the image used in illumination affects the number of the materials differ. Explain the examples of a technically precise result. Assigned two example, the teaching for online counselling session has. If the object scatters light. Opaque objects examples intersecting volumes clad in translucency rating increases with textiles and we examined the example of these materials, it can you? Learn from objects examples of translucency controls are called translucent object has a great instructors. Opaque materials which the example of light to authenticated users to work the question together your new class can exit this activity to contact with. Please reload this means cannot see through a lahu man smoking against the of examples of how the choice between a few moving parts that a meaning they transmit. You study the object is. Here ߤ and examples of object looktranslucent or water spray, they interact with every day. Raft product for example of objects, the patterns and to. Students to object, but it allows us improve the example of material appears here is. Emailing our online counselling session expired game yet when describing phenomena such objects? You some examples of translucency image as an example of. -
Chapter 19/ Optical Properties
Chapter 19 /Optical Properties The four notched and transpar- ent rods shown in this photograph demonstrate the phenomenon of photoelasticity. When elastically deformed, the optical properties (e.g., index of refraction) of a photoelastic specimen become anisotropic. Using a special optical system and polarized light, the stress distribution within the speci- men may be deduced from inter- ference fringes that are produced. These fringes within the four photoelastic specimens shown in the photograph indicate how the stress concentration and distribu- tion change with notch geometry for an axial tensile stress. (Photo- graph courtesy of Measurements Group, Inc., Raleigh, North Carolina.) Why Study the Optical Properties of Materials? When materials are exposed to electromagnetic radia- materials, we note that the performance of optical tion, it is sometimes important to be able to predict fibers is increased by introducing a gradual variation and alter their responses. This is possible when we are of the index of refraction (i.e., a graded index) at the familiar with their optical properties, and understand outer surface of the fiber. This is accomplished by the mechanisms responsible for their optical behaviors. the addition of specific impurities in controlled For example, in Section 19.14 on optical fiber concentrations. 766 Learning Objectives After careful study of this chapter you should be able to do the following: 1. Compute the energy of a photon given its fre- 5. Describe the mechanism of photon absorption quency and the value of Planck’s constant. for (a) high-purity insulators and semiconduc- 2. Briefly describe electronic polarization that re- tors, and (b) insulators and semiconductors that sults from electromagnetic radiation-atomic in- contain electrically active defects. -
Super-Resolution Imaging by Dielectric Superlenses: Tio2 Metamaterial Superlens Versus Batio3 Superlens
hv photonics Article Super-Resolution Imaging by Dielectric Superlenses: TiO2 Metamaterial Superlens versus BaTiO3 Superlens Rakesh Dhama, Bing Yan, Cristiano Palego and Zengbo Wang * School of Computer Science and Electronic Engineering, Bangor University, Bangor LL57 1UT, UK; [email protected] (R.D.); [email protected] (B.Y.); [email protected] (C.P.) * Correspondence: [email protected] Abstract: All-dielectric superlens made from micro and nano particles has emerged as a simple yet effective solution to label-free, super-resolution imaging. High-index BaTiO3 Glass (BTG) mi- crospheres are among the most widely used dielectric superlenses today but could potentially be replaced by a new class of TiO2 metamaterial (meta-TiO2) superlens made of TiO2 nanoparticles. In this work, we designed and fabricated TiO2 metamaterial superlens in full-sphere shape for the first time, which resembles BTG microsphere in terms of the physical shape, size, and effective refractive index. Super-resolution imaging performances were compared using the same sample, lighting, and imaging settings. The results show that TiO2 meta-superlens performs consistently better over BTG superlens in terms of imaging contrast, clarity, field of view, and resolution, which was further supported by theoretical simulation. This opens new possibilities in developing more powerful, robust, and reliable super-resolution lens and imaging systems. Keywords: super-resolution imaging; dielectric superlens; label-free imaging; titanium dioxide Citation: Dhama, R.; Yan, B.; Palego, 1. Introduction C.; Wang, Z. Super-Resolution The optical microscope is the most common imaging tool known for its simple de- Imaging by Dielectric Superlenses: sign, low cost, and great flexibility. -
(12) United States Patent (10) Patent No.: US 9.410,246 B2 Winarski (45) Date of Patent: *Aug
USOO941.0246B2 (12) United States Patent (10) Patent No.: US 9.410,246 B2 Winarski (45) Date of Patent: *Aug. 9, 2016 (54) GRAPHENEOPTICFIBER LASER (58) Field of Classification Search CPC .............................. H01S 3/067; G02B6/0229 (71) Applicant: Tyson York Winarski, Mountain View, See application file for complete search history. CA (US)(US (56) References Cited (72) Inventor: feYork Winarski, Mountain View, U.S. PATENT DOCUMENTS - 2007/0030558 A1* 2, 2007 Martinelli ........ HO4B 10,25133 (*) Notice: Subject to any disclaimer, the term of this 359,334 patent is extended or adjusted under 35 2011/0222562 A1* 9/2011 Jiang ....................... HO1S 3,067 U.S.C. 154(b) by 0 days. 372/6 2011/0285999 A1* 11/2011 Kim ..................... GO1N 21,552 This patent is Subject to a terminal dis- 356,445 claimer. 2012/0039344 A1 2/2012 Kian ....................... HO1S 3,067 372/6 (21) Appl. No.: 14/710,592 2014/0341238 A1*ck 1 1/2014 Kitabayashi .......... HO1S 39. (22) Filed: May 13, 2015 OTHER PUBLICATIONS O O Ariel Ismach, Clara Druzgalski, Samuel Penwell, Adam (65) Prior Publication Data Schwartzberg, Maxwell Zheng, Ali Javey, Jeffrey Bokor, and US 2015/O255945A1 Sep. 10, 2015 Yuegang Zhang, Direct Chemical Vapor Deposition of Graphene on Dielectric Surfaces, Nano Lett. 2010, 10, 1542-1548, American Chemical Society, Apr. 2, 2010. Related U.S. Application Data Rui Wang, Yufeng Hao, Ziqian Wang, Hao Gong, and John T. L. Thong in Large-Diameter Graphene Nanotubes Synthesized Using (63) Continuation-in-part of application No. 14/070,574, Ni Nanowire Templates, Nano Lett. 2010, 10, 4844-4850, American filed on Nov.