Glossary of Laser Terms Absorb to Transform Radiant Energy Into a Different Form, with a Resultant Rise in Temperature. Absorpt
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A Novel and Cost Effective Radiant Heat Flux Gauge This Paper Presents a Patent-Pending Methodology of Measuring Radiation Emiss
A Novel and Cost Effective Radiant Heat Flux Gauge S. Safaei and A. S. Rangwala Department of Fire Protection Engineering, Worcester Polytechnic Institution, Worcester, MA, 01609, USA V. Raghavan Department of Mechanical Engineering Indian Institute of Technology Madras, Chennai, India T.M. Muruganandam, Department of Aerospace Engineering, National Center for Combustion Research and Development, Indian Institute of Technology Madras, Chennai, India This paper presents a patent-pending methodology of measuring radiation emissions from fires, for the purposes of more practical optical flame detection and analysis. Flame radiation comprises of three phenomena: chemiluminescence, photoluminescence, and thermal radiation. The first two types are caused by elementary breakdown reactions of the reactants and the molecular excitations of products such as H2O and CO2, respectively. These emissions are within narrow bands of electromagnetic radiation wavelengths, and due to their specific molecular physics, are largely fuel dependant. The third type, thermal radiation emissions come from high temperature soot, which is a blanket term for any carbonaceous intermittent species of the combustion reaction. The amount and temperature of soot is case-specific, as it is influenced by fuel type, geometries, fuel-oxidizer premixing and the resulting level of combustion efficiency. However since naturally occurring fire hazards are diffusion flames, soot is present in high quantities and the majority of the radiation can be attributed to soot alone [1 – 2]. These soot emissions are over large ranges of the electromagnetic spectrum, from ultraviolet all the way to Long wave Infrared (LWIR), following the classic Planck Law for Blackbody emitters. This distribution of radiant energy, E, is highly dependent on the temperature of the emitter, T, due to its exponential relation E=T4. -
A Tunable Mode-Locked Ytterbium-Doped Fiber Laser Based on Nonlinear Kerr Beam Clean-Up Effect
A tunable mode-locked ytterbium-doped fiber laser based on nonlinear Kerr beam clean-up effect Shanchao Ma,1 Baofu Zhang,2,* Qiurun He,1 Jing Guo,3 and Zhongxing Jiao1,* 1School of Physics, Sun Yat-sen University, Guangzhou 510275, China 2School of Materials Science and Engineering, Dongguan University of Technology, Dongguan 523808, China 3School of Opto-Electronics, Beijing Institute of Technology, Beijing 100081, China *Corresponding author: [email protected], [email protected] Abstract:We demonstrate a novel approach to achieve tunable ultrashort pulses from an all-fiber mode-locked laser with a saturable absorber based on nonlinear Kerr beam clean-up effect. This saturable absorber was formed by a single-mode fiber spliced to a commercial graded-index multimode fiber, and its tunable band-pass filter effect has been studied by an original numerical model. By adjusting the bending condition of graded-index multimode fiber, the laser could produce dissipative soliton pulses with their central wavelength tunable from1033 nm to 1063 nm. The pulse width of output laser could be compressed externally to 791 fs, and the signal to noise ratio of its radio frequency spectrum was measured to be 75.5 dB. This work provides a new idea for the design of tunable mode-locked laser which can be used as an attractive light source in optical communication system. 1. Introduction Wavelength tunable lasers are widely used in optical communication [1], detection [2], and remote sensing [3]. Compared to tunable continuous-wave lasers, tunable mode-locked lasers can generate ultra-short pulses with high peak power and wide bandwidth that enable many important advances, such as high-sensitivity optical absorption measurement [4], multi photon microscopy [5], and super-continuum light source used in dense wavelength division multiplexing [6]. -
Tunable Laser Absorption Spectroscopy for Human Spaceflight
49th International Conference on Environmental Systems ICES-2019-358 7-11 July 2019, Boston, Massachusetts Tunable Laser Absorption Spectroscopy for Human Spaceflight Christopher M Matty1 and Lance E Christensen2 National Aeronautics and Space Administration, Houston Texas 77058 and Pasadena California 91109 Human Spaceflight consistently has need for measurement of the major constituent gasses in a habitable cabin environment. Traditionally, this measurement has been performed using a mixture of mass spectrometry, electrochemical, and other traditional sensing methods. Tunable laser spectroscopy has been used in industry and research applications since the 1970s but has not been used in primary operational human spaceflight systems aside from a handful of experimental applications. Meanwhile, recent advances in the quality, size, and cost of semiconductor lasers has had a significant impact on the range of feasible applications for tunable laser spectroscopy. In 2018, work started on the Orion Laser Air Monitor (LAM), which is designed to be the primary major constituency monitoring system for the Orion Spacecraft. This paper covers the history leading up to the selection, design, and build of the Orion Laser Air Monitor as a primary major constituent analyzer for human spaceflight. Nomenclature TLDAS = Tunable Laser Diode Absorption Spectroscopy QC = Quantum Cascade IC = Interband Cascade TEC = Thermo Electric Cooler TRL = Technology Readiness Level SWAP = System Size Weight and Power IR = Infrared MCA = International Space Station Major Constituent Analyzer CAMS = Submarine Central Atmosphere Monitoring System AGA = Anomaly Gas Analyzer MGM = Multi Gas Monitor CPM = Combustion Product Monitor LAM = Laser Air Monitor SAFFIRE = Spacecraft Fire Experiement GaSb = Gallium Antimodide I. Introduction UNABLE Laser Diode Absorption Spectroscopy (TLDAS) is currently enjoying a period at the developmental Tforefront. -
Low Cost Solar Thermoelectric Water Floating Device to Supply Measurement Platform
78 IAPGOŚ 4/2019 p-ISSN 2083-0157, e-ISSN 2391-6761 DOI: 10.35784/IAPGOS.734 LOW COST SOLAR THERMOELECTRIC WATER FLOATING DEVICE TO SUPPLY MEASUREMENT PLATFORM Andrzej Nowrot1, Monika Mikołajczyk2, Anna Manowska1, Joachim Pielot1, Antoni Wojaczek1 1Silesian University of Technology, Department of Electrical Engineering and Automation in Industry, Gliwice, Poland, 2Famur Institute Ltd, Katowice, Poland Abstract. This work presents the prototype of the solar – thermoelectric device, which can float on water surface. It produces electrical energy as a result of the Seebeck effect in a commercial, low-cost Peltier module. The main application of the device will be an autonomous and a floating measurement platform. An important advantage of the presented solution is the possibility to work alike at day, when a solar light heats the surface of the absorber, and at night, when the different of temperatures between air and water causes the heat flux and in an effect the electricity. The device is capable of working for many cloudy days and also in winter on very short days. The presented device is based on low-cost and widely available components. Keywords: thermoelectric devices, solar power generation, energy conversion TERMOELEKTRYCZNE URZĄDZENIE SOLARNE DO ZASILANIA PLATFORMY POMIAROWEJ Streszczenie. W pracy zaprezentowano prototypowe solarne urządzenie termoelektryczne pływające po powierzchni wody. Wytwarza ono w niedrogim, komercyjnym module Peltiera energię elektryczną w wyniku zachodzącego w nim zjawiska Seebecka. Docelowo głównym obszarem aplikacyjnym urządzenia będzie zasilanie autonomicznej, pływającej platformy pomiarowa do monitorowania parametrów środowiskowych. Istotną zaletą przedstawionego rozwiązania jest możliwość pracy zarówno w dzień, gdy światło słoneczne ogrzewa powierzchnię absorbera, jak również w nocy, gdy różnica temperatur między powietrzem a wodą powoduje powstawanie strumienia ciepła w module Peltiera. -
United States Patent [191 4,2313J97 Sher
United States Patent [191 4,2313J97 Sher [54] RADIANT ENERGY TO ELECTRIC ENERGY 4,084,101 4/1978 Sher ..................................... 290/1 R CONVERTER 4,096,393 6/1978 Sher ..................................... 290A R [76] Inventor: Arden Sher, 108 Charles River OTHER PUBLICATIONS Landing Rd., Williamsburg, Va. R. Solomon et al., “Polarization in LaF,”, J. Appl. Phys., 23185 VO~.37, pp. 3427-3432, (1966). [ * 3 Notice: The portion of the term of this patent A. Sher et al., “Transport Properties of LaF3”, Phys. subsequent to Apr. 11,1995, has been Rev., vol. 144, pp. 593-604, (1966). disclaimed. J. E. Drummond, “Electrical Power Conversion”, IECEC Record ’75, pp. 569-575. [21] Appl. No.: 889,514 S. B. Skinner, “Thermodielectric Energy Conversion [22] Filed: Mar. 23,1978 by Thin Films: Experiment & Theory”, Intersociety Energy Conv. Eng. Con$, (1967), pp. 865-873. Related U.S. Application Data A. Sher et al., “LaF3 Infrared Detector”, Appl. Phys. Lett., vol. 28, pp. 676-678, (1976). [63] Continuation-in-part of Ser. No. 631,689, Nov. 13, 1975, Pat. No. 4,084,101. Primary Examiner-Aaron Weisstuch Attorney, Agent, or Firm-Lowe, King, Price and [51] Int. Cl.2 ............................................. HQlL31/Q4 Becker [52] U.S. Cl. ............................... 136/89 SP; 290/1 R 361/280; 361/282; 310/308; 310/309; 250/211 1571 ABSTRACT 250/212; 250/336 R; Radiant energy is converted into electric energy by [58] Field of Search ............ 136/89 R, 89 NB, 89 SP; irradiating a capacitor including an ionic dielectric. The 250/211 R, 212, 336; 290/1 R 361/280,282; 310/308, 309 dielectric is a sintered crystal superionic conductor, e.g., lanthanum trifluoride, lanthanum trichloride, or [561 References Cited silver bromide, so that a multiplicity of crystallites exist U.S. -
LESSON 1 What Is Energy?
LESSON 1 What is Energy? Overview In this lesson students review what they know about energy in everyday life, define it, learn the different energy forms through play, and differentiate between potential and kinetic energy. Student • I can use my own words to show I understand “energy.” Learning • I can describe the main forms of energy and give examples. Targets • I can show potential and kinetic energy with my body and I can give examples of each. • I can give examples of how I use energy every day. NGSS MS-PS3-5. Construct, use, and present arguments to support the claim that when the kinetic energy of an object changes, energy is transferred to or from the object. [Clarification Statement: Examples of empirical evidence used in arguments could include an inventory or other representation of the energy before and after the transfer in the form of temperature changes or motion of object.] [Assessment Boundary: Assessment does not include calculations of energy.] Background Energy is part of everything that happens in the world and everything we do. Energy can be in the form of heat, light, gravity, sound, motion, chemical reactions, or electricity. Energy is the ability to do work or make a change. Nine forms of energy: (see Overhead 1 “Forms of Energy”) • Chemical: Chemical energy is the energy stored in the bonds of atoms and molecules. Biomass, petroleum, natural gas, propane and coal are examples of stored chemical energy. • Nuclear: Nuclear energy is the energy stored in the nucleus of an atom. It is the energy that holds the nucleus together. -
Far Infrared Radiation Exposure
INTERNATIONAL COMMISSION ON NON‐IONIZING RADIATION PROTECTION ICNIRP STATEMENT ON FAR INFRARED RADIATION EXPOSURE PUBLISHED IN: HEALTH PHYSICS 91(6):630‐645; 2006 ICNIRP PUBLICATION – 2006 ICNIRP Statement ICNIRP STATEMENT ON FAR INFRARED RADIATION EXPOSURE The International Commission on Non-Ionizing Radiation Protection* INTRODUCTION the health hazards associated with these hot environ- ments. Heat strain and discomfort (thermal pain) nor- THE INTERNATIONAL Commission on Non Ionizing Radia- mally limit skin exposure to infrared radiation levels tion Protection (ICNIRP) currently provides guidelines below the threshold for skin-thermal injury, and this is to limit human exposure to intense, broadband infrared particularly true for sources that emit largely IR-C. radiation (ICNIRP 1997). The guidelines that pertained Furthermore, limits for lengthy infrared exposures would to infrared radiation (IR) were developed initially with an have to consider ambient temperatures. For example, an aim to provide guidance for protecting against hazards infrared irradiance of 1 kW mϪ2 (100 mW cmϪ2)atan from high-intensity artificial sources and to protect work- ambient temperature of 5°C can be comfortably warm- ers in hot industries. Detailed guidance for exposure to ing, but at an ambient temperature of 30°C this irradiance longer far-infrared wavelengths (referred to as IR-C would be painful and produce severe heat strain. There- radiation) was not provided because the energy at longer fore, ICNIRP provided guidelines to limit skin exposure wavelengths from most lamps and industrial infrared to pulsed sources and very brief exposures where thermal sources of concern actually contribute only a small injury could take place faster than the pain response time fraction of the total radiant heat energy and did not and where environmental temperature and the irradiated require measurement. -
Detection of Chemical Clouds Using Widely Tunable Quantum Cascade Lasers
Detection of chemical clouds using widely tunable quantum cascade lasers Anish K. Goyal*, Petros Kotidis, Erik R. Deutsch, Ninghui Zhu, Mark Norman, Jim Ye, Kostas Zafiriou, and Alex Mazurenko Block Engineering/MEMS, 377 Simarano Drive, Marlborough, MA 01752 ABSTRACT Widely tunable quantum cascade lasers (QCLs) spanning the long-wave infrared (LWIR) atmospheric transmission window and an HgCdTe detector were incorporated into a transceiver having a 50-mm-diameter transmit/receive aperture. The transceiver was used in combination with a 50-mm-diameter hollow retro-reflector for the open-path detection of chemical clouds. Two rapidly tunable external-cavity QCLs spanned the wavelength range of 7.5 to 12.8 m. Open-path transmission measurements were made over round-trip path-lengths of up to 562 meters. Freon-132a and other gases were sprayed into the beam path and the concentration-length (CL) product was measured as a function of time. The system exhibited a noise-equivalent concentration (NEC) of 3 ppb for Freon-132a given a round-trip path of 310 meters. Algorithms based on correlation methods were used to both identify the gases and determine their CL- products as a function of time. Keywords: atmospheric sensing, open-path spectroscopy, gas detection, vibrational spectroscopy, infrared spectroscopy, quantum cascade lasers, chemical detection 1. INTRODUCTION Open-path atmospheric spectroscopy is used to measure the gas concentration along an optical path. There are many such systems and they operate within one or more of the atmospheric transmission bands that exist between the ultraviolet (UV) and mid-infrared (MIR) portions of the optical spectrum [1-4]. -
Black Body Radiation and Radiometric Parameters
Black Body Radiation and Radiometric Parameters: All materials absorb and emit radiation to some extent. A blackbody is an idealization of how materials emit and absorb radiation. It can be used as a reference for real source properties. An ideal blackbody absorbs all incident radiation and does not reflect. This is true at all wavelengths and angles of incidence. Thermodynamic principals dictates that the BB must also radiate at all ’s and angles. The basic properties of a BB can be summarized as: 1. Perfect absorber/emitter at all ’s and angles of emission/incidence. Cavity BB 2. The total radiant energy emitted is only a function of the BB temperature. 3. Emits the maximum possible radiant energy from a body at a given temperature. 4. The BB radiation field does not depend on the shape of the cavity. The radiation field must be homogeneous and isotropic. T If the radiation going from a BB of one shape to another (both at the same T) were different it would cause a cooling or heating of one or the other cavity. This would violate the 1st Law of Thermodynamics. T T A B Radiometric Parameters: 1. Solid Angle dA d r 2 where dA is the surface area of a segment of a sphere surrounding a point. r d A r is the distance from the point on the source to the sphere. The solid angle looks like a cone with a spherical cap. z r d r r sind y r sin x An element of area of a sphere 2 dA rsin d d Therefore dd sin d The full solid angle surrounding a point source is: 2 dd sind 00 2cos 0 4 Or integrating to other angles < : 21cos The unit of solid angle is steradian. -
Improved Laser Based Photoluminescence on Single-Walled Carbon Nanotubes
Improved laser based photoluminescence on single-walled carbon nanotubes S. Kollarics,1 J. Palot´as,1 A. Bojtor,1 B. G. M´arkus,1 P. Rohringer,2 T. Pichler,2 and F. Simon1 1Department of Physics, Budapest University of Technology and Economics and MTA-BME Lend¨uletSpintronics Research Group (PROSPIN), P.O. Box 91, H-1521 Budapest, Hungary 2Faculty of Physics, University of Vienna, Strudlhofgasse 4., Vienna A-1090, Austria Photoluminescence (PL) has become a common tool to characterize various properties of single- walled carbon nanotube (SWCNT) chirality distribution and the level of tube individualization in SWCNT samples. Most PL studies employ conventional lamp light sources whose spectral dis- tribution is filtered with a monochromator but this results in a still impure spectrum with a low spectral intensity. Tunable dye lasers offer a tunable light source which cover the desired excitation wavelength range with a high spectral intensity, but their operation is often cumbersome. Here, we present the design and properties of an improved dye-laser system which is based on a Q-switch pump laser. The high peak power of the pump provides an essentially threshold-free lasing of the dye laser which substantially improves the operability. It allows operation with laser dyes such as Rhodamin 110 and Pyridin 1, which are otherwise on the border of operation of our laser. Our sys- tem allows to cover the 540-730 nm wavelength range with 4 dyes. In addition, the dye laser output pulses closely follow the properties of the pump this it directly provides a time resolved and tunable laser source. -
Electrically Tunable Mode-Locked Lasers Based on Time-To-Wavelength Mapping for Optical Communications
Laser Original Electrically Tunable Mode-Locked Lasers Based on Time-to-Wavelength Mapping for Optical Communications Kohichi R. TAMURA NTT Corporation, NTT Network Innovation Laboratories, 1-1 Hikari-no-oka, Yokosuka, Kanagawa 239-0847 (Received August 20, 2001) The tunable mode-locked laser based on time-to-wavelength mapping is a relatively unexplored alternative to tunable sources that can be applied to transmission and wavelength switching in optical networks. These lasers have the advantages of a simple tuning mechanism, good wavelength reproducibility, and simple cavity design. The state of research is discussed. Key Words: Tunable laser, Mode-locked laser, Fiber Bragg grating, Arrayed waveguide grating 1. Introduction ment to make a cavity with a length that depends on wavelength. The oscillation wavelength is selected by changing a single elec- Compact and tunable lasers are considered to be key compo- trical control signal - the RF frequency. The dependence of the nents for realizing advanced functionality in optical communi- oscillation wavelength on RF frequency is determined by the cation networks.1) A variety of designs exist, and, currently, sev- delay element and should be stable over time if a stable wave- eral of them are in the early stages of commercialization. The length-selective element is used. Inherent drawbacks to ETMLs first application of tunable lasers will be as temporary sources are the changing repetition rate with wavelength and the broad for DWDM terminals, which eliminates the need for stocking optical spectrum that results from mode-locking. Even so, as spare parts at each wavelength. While the tuning speed is not we describe below, these lasers may find applications in optical critical in this case, more advanced applications call for speeds switching within nodes or for short distance transmission in ranging from millisecond-to-nanosecond time scales. -
Fine Fuel Heating by Radiant Flux
Combust. Sci. and Tech., 182: 215–230, 2010 Copyright # Taylor & Francis Group, LLC ISSN: 0010-2202 print=1563-521X online DOI: 10.1080/00102200903341538 FINE FUEL HEATING BY RADIANT FLUX David Frankman,1 Brent W. Webb,1 Bret W. Butler,2 and Don J. Latham2 1Department of Mechanical Engineering, Brigham Young University, Provo, Utah, USA 2Rocky Mountain Research Station, U.S. Forest Service Fire Sciences Laboratory, Missoula, Montana, USA Experiments were conducted wherein wood shavings and Ponderosa pine needles in quiescent air were subjected to a steady radiation heat flux from a planar ceramic burner. The internal temperature of these particles was measured using fine diameter (0.076 mm diameter) type K thermocouples. A narrow angle radiometer was used to determine the emissive power generated by the burner. A model was developed to predict the steady-state temperature of a cylindrical particle with an imposed radiation heat flux under both quiesc- ent air (buoyancy-induced cooling) and windy (forced convection cooling) conditions. Excellent agreement was observed between the model predictions and the experimental data. Parametric studies using the validated model explore the effect of burner (flame) tem- perature and distance, fuel size, and wind speed. The data suggest that ignition of the fuel element by radiation heating alone is likely only under circumstances where the fire is very intense (such as crown fires), and even then may still be dependent on pilot ignition sources. Keywords: Fine fuel; Heating; Radiation INTRODUCTION Radiation and convection heat transfer have complimentary roles in wildland fire spread (Anderson, 1969), but due to the complexity of the wildland fire environ- ment, they remain largely undetermined.