Terahertz spectroscopy measurements
|
|
- Kimberly Fitzgerald
- 5 years ago
- Views:
Transcription
1 0 Terahertz spectroscopy measurements For general medicine and pharmacy students author: József Orbán, PhD. teaching facility: Univerity of Pécs, Medical School Department of Biophysics research facility: MTA TKI High-Field Terahertz Research Group Pécs, november 25.
2 Terahertz spectroscopy measurements For general medicine and pharmacy students Spectroscopy background Similarly to the ultraviolet (UV), visible (VIS) and infrared (IR) spectroscopy the electromagnetic radiation in the terahertz (THz: 1012 Hz) frequency range can also be used for spectroscopy and can provide useful information about the energy state and vibrations of molecules. The terahertz frequency falls into the far infrared range and is on the short wavelength edge of the microwave range of the total electromagnetic spectrum (1. figure). As in case of UV/VIS/IR spectroscopy the most used and basic measurement method is based on the measurement of absorption of radiation transmitted through the studied sample, the terahertz radiation can be used this simple way as well. The relative decrease of radiation intensity requires in all cases a so called control measurement to which the sample transmitted intensity is compared. The measurement is performed in two steps control and sample measurement as for all single path spectroscopes. The absorption can be calculated by the following formula: 1. equation X-ray and gamma ultraviolet visible infrared microwaves radiowaves in which I and I0 are the transmitted intensities for the sample and for the control measurements calculated for each wavelength (λ) of the spectrum, correspondingly. 1. figure: Terahertz radiation falls into the far infrared (FIR) range of the total electromagnetic spectrum. The sample is placed between the source of the radiation (called emitter) and the detector. The control measurement is performed either without sample or in case of solutions the solvent is used without the molecule of our interest (solute). 1
3 amplitude amplitude The terahertz spectrometer 2 The source of the terahertz radiation is a short time pulsed laser (3. figure) providing ~100 femtosecond (fs: s) time long pulses. These laser pulses generate similarly ~100 fs long terahertz pulses. These pulses contain energy on a wider range of frequency (0-5 THz) hence are not monochromatic. The energy packed in the pulses has a typical intensity-time distribution profile (see 2. figure). The absorbance spectrum can be calculated with high precision on a limited frequency range (0,2-3 THz) using the available instrument (Menlo Systems K8 THz spectrometer). The calculated absorbance values at the edges of the total frequency range (0-5 THz) have low reliability, are not acceptable for spectroscopy. A B time time 2. figure: The change of electric field in time of a typical THz impulse. The real signal shape (A) and the measured amplitudes at discrete time intervals (B) are shown. Varying the density of data points the achievable precision of information can be influenced. The beam of terahertz impulses originated from the emitter is focused onto the sample using appropriate lenses. Passing the substance, the diverging beam is gathered with a similar lens to the focusing lens and is finally directed to the detector (3. figure). Both the emitter and the detector are optically gated dipole antennas. The previous one emits THz frequency radiation when the incoming laser impulse creates varied electric field strength between the two poles of the antenna. The latter one converts THz pulses to electric signal that is proportional to the electric field strength of the incoming THz pulse. This signal is acquired and processed by an electronic device, called lock-in amplifier. The emitter is switched on and off by a high frequency electric (square-wave) signal, thus the lock-in amplifier can compare the signal produced by the detector in on and off state. The signal of the latter case is subtracted from the first and thus the signal is corrected for background noise, hence the signal-to-noise ratio is increased. This background subtraction is repeated several times by the lock-in amplifier and as a consequence with long time integrating the noise reduced signals, the instrument eliminates further random measurement errors. The laser impulses are split in 50-50% ratio by a beamsplitter to create two pathes for the measurement: the emitter and the detector beams (3. figure). The first goes to the emitter and is responsible for the formation of THz pulses, the latter switches the photoswitchable detecting antenna on and off. The pulses arriving to the detector
4 sample antenna makes it sensitive for a short time consistent with the period of the incoming laser pulses (~100 fs is the detection time window for each pulses). 3 fs timed, pulsed laser 50-50% delay line emitter detector electric pulse generator lock-in amplifier 3. figure: Schematic drawing of the function of a terahertz spectrometer. The electric units are labeled blue, the optical ones are shown in red. Dashed red lines correspond to the path of pulsed laser and THz beams. The 50-50% ratio beamsplitter divides the laser light into emitter and detector beams. The pulses travelling in the detector beam path can be delayed in time compared to the pulses propagating in the emitter path using the delay line unit (DLU). This optomechanic device is retroflecting a beam parallel to the incident beam and its position can be varied thus the flight time of pulses can be precisely altered. As a consequence the time resolution of the system is defined on optical/geometrical positioning bases. This laserlight pulse based optical control permits us to study the THz signal transmitted through the sample down to 100 fs time steps that is the time resolution of the system. At the same time it means that the transmitted THz pulse is not measured from only one single pulse but from chosen finite number of measurements at different time points of the total time range of the THz signal. With this step-by-step measurement we perform an approximation process to gain the real shape of the pulse in time (2. figure). This setup requires the delay line unit (DLU) that we can position by 1 micrometer precision. Keep in mind that the light in 10 fs travels 3 microns only (this can be calculated using the propagation speed of light in vacuum; c m/s). Important fact is that the laser pulses directed to and reflected from the DLU by an increase of 15 microns in pathlength results in a double; 30 micron space delay that corresponds to 100 fs time delay. This way the pulses travelling in the detector path are delayed by 100 fs compared to the pulses propagating in the emitter beam. As a consequence, by steps of (at least) 15 micrometers in the detection path we can measure the sample transmitted THz signal by steps of 100 fs (at least).
5 Time domain frequency domain transformation 12 FFT amplitude (a.u.) The THz pulses formed by the emitter are energy quanta limited in space and time propagating in one direction from the emitter toward the detector in our case. The finite number intensity data measured at different time points define the intensitytime function which should be converted to intensity-frequency (or intensity-wavelength) function that is called spectrum ,0 0,5 1,0 1,5 frequency (THz) 2,0 This function defines the amount of energy 4. figure: the spectrum (amplitude-frequency plot) (or intensity) brought by the pulse at a given of a THz pulse that propagated in air containing vapour (dew) of water. The absorption peaks of frequency (4. figure). The Fast Fourier water can be seen as valleys on the curve. Transformation (FFT) is used to convert time domain data to frequency domain data (spectrum). According to the simplified mathematical background we can state that all types of (periodic) signal in time can be described as a sum of sinus signals with independent periodicity and amplitudes. A simple and single sinus signal s intensity at any moment of time (I(t)) is defined by the sinus function s frequency (ω) and amplitude (A): 2. equation Therefore a complex signal can be written in the following form: 3. equation where k is the number of the components. To rewrite it in a more elegant way let s use the sum function (i is integer number, varied from zero to k): 4. equation The signal decomposed to its components has number k pairs of characterizing data: the defined values of frequencies (ωi) and the related amplitudes (Ai). If we plot these amplitudes against the related frequencies then we get the spectrum. In the complicated (discrete) Fourier transformation the signal is decomposed in the space of complex numbers: 5. equation where ω0 is the base frequency, N is the number of elements in the data (pair) set, k is a constant proportional to a selected frequency and ejωt=cos(kω0t)+j sin(kω0t). For further explanation of FFT method please find appropriate mathematical books. Applying the Fast Fourier Transformation method (FFT) with some useful considerations and simplifications the computational time requirement and the complexiticity can be significantly decreased. Using computers and softwares of nowadays these FFT calculations can be easily performed even for large data sets.
6 Application of Terahertz spectroscopy 5 The terahertz frequency range can be used to study weak chemical bonds (i.e. hydrogen, van der Waals bonds), or the low frequency intra- and intermolecular vibrations. The molecular transitions in the microsecond-picosecond range probed by THz radiation supplement our knowledge of different energy and time scaled vibrations. The IR spectroscopy is appropriate to probe the fs-ps ( s) and the electron paramagnetic resonance (EPR) spectroscopy the μs-ms ( s) time scaled molecular changes and vibrations. Due to the recent development of THz radiation emitting sources it is possible to study biological molecules (peptides and proteins) and their hydration shell, as well. The water molecules forming the hydration shell have role in the function of proteins and also in the intestinal absorption of drugs and nutrition. The water highly absorbs the infrared radiation, including THz waves. When we perform a measurement the relative humidity in the air must be precisely controlled and kept constant. This is an important precondition of comparable control and sample measurements. The best solution is if we can decrease the relative humidity below 5% some way. At well-defined frequencies characteristic water absorption lines show up (see: 4. figure). These specific lines are related to hydrogen bonds and vibrations of water molecules. Water based solutions can be measured in infrared and in THz spectroscopy if the sample width is less than μm, otherwise the water absorption hides the studied molecule s (solute) own absorption. Finally, it is important to note that similarly to UV spectroscopy THz requires special materials having low absorption in the THz regime, with other words THz-transparent materials if it is possible it can also be transparent in visible range. Principally thin walled plastic (teflon, high density polyethylene, etc.) containers or cuvettes are used for this purpose. Measurement method Using the available time-domain terahertz spectroscope (Menlo Systems K8 TDTS) we can study molecules having well defined absorption lines in the THz range. Chemically not bound, separate amino acids, nucleic acids have characteristic absorption spectra in the 0-3 THz range (limits of the indicated instrument). The water-free powder form of the molecules should be placed to the appropriate plastic sample holder. Sample preparation is easy; none of the dry powders require further precautions. After starting the spectroscope and optimizing the amplitude of the THz pulses the first step is to set the delay line unit to a position that corresponds to equal path lengths in the emitter and detector paths. This is the starting point for further settings and the zero time point of the signal is defined this way at the same time. Good quality measurement can be achieved by appropriate time steps (0,1 ps = 100 fs). The THz signal is only ~100 fs long, but passing the sample it widens thus the best is to gather data from a 60 picosecond ( s) time range. To receive a good quality FFT transformation result we should precisely define the zero signal level that can be done by collecting data 5-10 ps
7 before the THz signal. As a consequence the total time window to measure turns to be around 70 ps. This results in ~700 data points applying the above defined time resolution. With these settings we may detect the shape of the THz signal with high enough precision. Please use appropriate names ( talkative names ) for the measurement files to facilitate the latter file searches. The name should include the name of the molecule, the name of the user, any further information that helps to recognize the file. 6 At the end compare the transmitted spectra of the THz signals of the sample and control measurements using the software based on FFT method. Compare the calculated absorption spectra in the 0-3 THz range corresponding to the different studied molecules. Make conclusions from the received spectra: the characteristics absorption frequencies, maximum amplitudes and the half width of the peaks. 1) Start the instrument (thermostating unit, laser power supply, lock-in amplifier, computer) 2) Start the spectroscope controller software. After the initialization step set the delay line unit s position to equal pathlengths in the detector and emitter beams. 3) The laser reaches the modus synchronized state helping to switch from continuous to pulse mode automatically. This step requires setting the temperature of the laser to 35ºC. In the next step find the optimal THz intensity leaving the emitter and reaching the detector by fine adjustment of the micrometer screws that moves the detector and emitter antennas. 4) Set the appropriate starting and ending DLU positions in the software. The measurement should start 5-10 ps earlier (important for determining the zero signal level) and 60 ps long time window for the signal and post signal period. Set the time steps to have at least data points leading to an approximate 0,1 ps (100 fs) time resolution. 5) Perform the control measurement. This may be the transmitted signal in air or through an empty sample holder (or filled with the buffer, but without the molecule of our interest). The sample holder should be placed right in the middle between the lenses of the emitter and detector. Save the reference measurement data with an appropriate name that helps to choose later this data as reference for sample measurements. 6) Replace the control substance or position the sample between the lenses and determine the transmitted THz signal for each sample separately. Save the results of the different molecules with corresponding names. 7) Calculate the transmission spectra for the control and for the sample(s) then determine the characteristic absorbance spectra for the different samples. Use either the ( ) 1. equation, or the FFT based software. 8) Make conclusions from spectroscopy viewpoint about the properties and characteristics of the absorption spectra. Can the different molecules be differentiated based on their spectra?
8 7 The present teaching material made by József Orbán (PhD), was supported by the European Union and the State of Hungary, co-financed by the European Social Fund in the framework of TÁMOP A/ 2-11/ National Excellence Program ( ). This material was made for the University of Pécs, Medical School, Department of Biophysics as a research associate at the MTA TKI High-Field Terahertz Research Group.
Instruction manual and data sheet ipca h
1/15 instruction manual ipca-21-05-1000-800-h Instruction manual and data sheet ipca-21-05-1000-800-h Broad area interdigital photoconductive THz antenna with microlens array and hyperhemispherical silicon
More informationz t h l g 2009 John Wiley & Sons, Inc. Published 2009 by John Wiley & Sons, Inc.
x w z t h l g Figure 10.1 Photoconductive switch in microstrip transmission-line geometry: (a) top view; (b) side view. Adapted from [579]. Copyright 1983, IEEE. I g G t C g V g V i V r t x u V t Z 0 Z
More informationSkoog Chapter 1 Introduction
Skoog Chapter 1 Introduction Basics of Instrumental Analysis Properties Employed in Instrumental Methods Numerical Criteria Figures of Merit Skip the following chapters Chapter 2 Electrical Components
More information4.6.1 Waves in air, fluids and solids Transverse and longitudinal waves Properties of waves
4.6 Waves Wave behaviour is common in both natural and man-made systems. Waves carry energy from one place to another and can also carry information. Designing comfortable and safe structures such as bridges,
More informationTerahertz Subsurface Imaging System
Terahertz Subsurface Imaging System E. Nova, J. Abril, M. Guardiola, S. Capdevila, A. Broquetas, J. Romeu, L. Jofre, AntennaLab, Signal Theory and Communications Dpt. Universitat Politècnica de Catalunya
More informationData sheet for TDS 10XX system THz Time Domain Spectrometer TDS 10XX
THz Time Domain Spectrometer TDS 10XX TDS10XX 16/02/2018 www.batop.de Page 1 of 11 Table of contents 0. The TDS10XX family... 3 1. Basic TDS system... 3 1.1 Option SHR - Sample Holder Reflection... 4 1.2
More informationNational 3 Physics Waves and Radiation. 1. Wave Properties
1. Wave Properties What is a wave? Waves are a way of transporting energy from one place to another. They do this through some form of vibration. We see waves all the time, for example, ripples on a pond
More informationElectromagnetic Spectrum
Electromagnetic Spectrum The electromagnetic radiation covers a vast spectrum of frequencies and wavelengths. This includes the very energetic gamma-rays radiation with a wavelength range from 0.005 1.4
More informationTerahertz Technologies
Terahertz Technologies Physics, Sources, and Applications SRJC, PHYS43 Spring 2013 Physics Terahertz corresponds with the frequencies between 100 GHz to 10 THz This rage is also called the Terahertz Gap
More informationQuantifying the energy of Terahertz fields using Electro-Optical Sampling. Tom George. LCLS, Science Undergraduate Laboratory Internship Program
Quantifying the energy of Terahertz fields using Electro-Optical Sampling Tom George LCLS, Science Undergraduate Laboratory Internship Program San Jose State University SLAC National Accelerator Laboratory
More information4.6 Waves Waves in air, fluids and solids Transverse and longitudinal waves
4.6 Waves Wave behaviour is common in both natural and man-made systems. Waves carry energy from one place to another and can also carry information. Designing comfortable and safe structures such as bridges,
More informationMODULE P6: THE WAVE MODEL OF RADIATION OVERVIEW
OVERVIEW Wave behaviour explains a great many phenomena, both natural and artificial, for all waves have properties in common. The first topic introduces a basic vocabulary for describing waves. Reflections
More informationInfrared Single Shot Diagnostics for the Longitudinal. Profile of the Electron Bunches at FLASH. Disputation
Infrared Single Shot Diagnostics for the Longitudinal Profile of the Electron Bunches at FLASH Disputation Hossein Delsim-Hashemi Tuesday 22 July 2008 7/23/2008 2/ 35 Introduction m eb c 2 3 2 γ ω = +
More informationTHz-Imaging on its way to industrial application
THz-Imaging on its way to industrial application T. Pfeifer Laboratory for Machine Tools and Production Engineering (WZL) of RWTH Aachen niversity Manfred-Weck Building, Steinbachstraße 19, D-52074 Aachen,
More informationKit for building your own THz Time-Domain Spectrometer
Kit for building your own THz Time-Domain Spectrometer 16/06/2016 1 Table of contents 0. Parts for the THz Kit... 3 1. Delay line... 4 2. Pulse generator and lock-in detector... 5 3. THz antennas... 6
More informationELECTROMAGNETIC SPECTRUM ELECTROMAGNETIC SPECTRUM
LECTURE:2 ELECTROMAGNETIC SPECTRUM ELECTROMAGNETIC SPECTRUM Electromagnetic waves: In an electromagnetic wave the electric and magnetic fields are mutually perpendicular. They are also both perpendicular
More informationUnit-23 Michelson Interferometer I
Unit-23 Michelson Interferometer I Objective: Study the theory and the design of Michelson Interferometer. And use it to measure the wavelength of a light source. Apparatus: Michelson interferometer (include
More informationTerahertz Spectroscopic/ Imaging Analysis Systems
Terahertz Spectroscopic/ Series Non-Destructive Analysis of Pharmaceuticals, Chemicals, Communication Materials, etc. Compact, High-Speed Terahertz Spectroscopic/ High-speed measurement functionality Compact,
More informationMonitoring the plant water status with terahertz waves
Monitoring the plant water status with terahertz waves Dr. Gunter Urbasch Experimental Semiconductor Physics AG Martin Koch Fachbereich Physik Experimentelle Halbleiterphysik Arbeitsgruppe M. Koch Gunter
More informationConceptual Physics Fundamentals
Conceptual Physics Fundamentals Chapter 13: LIGHT WAVES This lecture will help you understand: Electromagnetic Spectrum Transparent and Opaque Materials Color Why the Sky is Blue, Sunsets are Red, and
More informationPhotomixing THz Spectrometer Review
Photomixing THz Spectrometer Review Joseph R. Demers, PhD 9/29/2015 Leveraging Telecom Manufacturing Techniques to Improve THz Technology Terahertz Spectrum THz radiation was difficult to produce and detect
More informationChapter 23 Electromagnetic Waves Lecture 14
Chapter 23 Electromagnetic Waves Lecture 14 23.1 The Discovery of Electromagnetic Waves 23.2 Properties of Electromagnetic Waves 23.3 Electromagnetic Waves Carry Energy and Momentum 23.4 Types of Electromagnetic
More informationFirst Observation of Stimulated Coherent Transition Radiation
SLAC 95 6913 June 1995 First Observation of Stimulated Coherent Transition Radiation Hung-chi Lihn, Pamela Kung, Chitrlada Settakorn, and Helmut Wiedemann Applied Physics Department and Stanford Linear
More informationOptics & Light. See What I m Talking About. Grade 8 - Science OPTICS - GRADE 8 SCIENCE 1
Optics & Light See What I m Talking About Grade 8 - Science OPTICS - GRADE 8 SCIENCE 1 Overview In this cluster, students broaden their understanding of how light is produced, transmitted, and detected.
More informationLecture 19 Optical Characterization 1
Lecture 19 Optical Characterization 1 1/60 Announcements Homework 5/6: Is online now. Due Wednesday May 30th at 10:00am. I will return it the following Wednesday (6 th June). Homework 6/6: Will be online
More informationFigure1. To construct a light pulse, the electric component of the plane wave should be multiplied with a bell shaped function.
Introduction The Electric field of a monochromatic plane wave is given by is the angular frequency of the plane wave. The plot of this function is given by a cosine function as shown in the following graph.
More informationWaves. A wave is a disturbance which travels through a vacuum or medium (air, water, etc) that contains matter A wave transports ENERGY not matter
Waves and Optics Waves A wave is a disturbance which travels through a vacuum or medium (air, water, etc) that contains matter A wave transports ENERGY not matter Waves Some waves do not need a medium
More information6-6 Waves Trilogy. 1.0 Figure 1 shows an incomplete electromagnetic spectrum. Figure 1. A microwaves B C ultraviolet D gamma
6-6 Waves Trilogy.0 Figure shows an incomplete electromagnetic spectrum. Figure A microwaves B C ultraviolet D gamma. Which position are X-rays found in? Tick one box. [ mark] A B C D.2 Which three waves
More informationPROJECT REPORT COUPLING OF LIGHT THROUGH FIBER PHY 564 SUBMITTED BY: GAGANDEEP KAUR ( )
PROJECT REPORT COUPLING OF LIGHT THROUGH FIBER PHY 564 SUBMITTED BY: GAGANDEEP KAUR (952549116) 1 INTRODUCTION: An optical fiber (or fiber) is a glass or plastic fiber that carries light along its length.
More informationHuman Retina. Sharp Spot: Fovea Blind Spot: Optic Nerve
I am Watching YOU!! Human Retina Sharp Spot: Fovea Blind Spot: Optic Nerve Human Vision Optical Antennae: Rods & Cones Rods: Intensity Cones: Color Energy of Light 6 10 ev 10 ev 4 1 2eV 40eV KeV MeV Energy
More informationSection 1: Sound. Sound and Light Section 1
Sound and Light Section 1 Section 1: Sound Preview Key Ideas Bellringer Properties of Sound Sound Intensity and Decibel Level Musical Instruments Hearing and the Ear The Ear Ultrasound and Sonar Sound
More informationPhysics: Waves, Sound/Light, Electromagnetic Waves, Magnetism, Mains Electricity and the National Grid
6.7 Describe the method to measure the speed of sound in air and the speed of ripples on the water surface 7.5 Link the properties of EM waves to their practical application (triple 7.6 Apply knowledge
More informationBasic Components of Spectroscopic. Instrumentation
Basic Components of Spectroscopic Ahmad Aqel Ifseisi Assistant Professor of Analytical Chemistry College of Science, Department of Chemistry King Saud University P.O. Box 2455 Riyadh 11451 Saudi Arabia
More informationChapter 16 Light Waves and Color
Chapter 16 Light Waves and Color Lecture PowerPoint Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. What causes color? What causes reflection? What causes color?
More informationSpectral phase shaping for high resolution CARS spectroscopy around 3000 cm 1
Spectral phase shaping for high resolution CARS spectroscopy around 3 cm A.C.W. van Rhijn, S. Postma, J.P. Korterik, J.L. Herek, and H.L. Offerhaus Mesa + Research Institute for Nanotechnology, University
More informationScience 8 Unit 2 Pack:
Science 8 Unit 2 Pack: Name Page 0 Section 4.1 : The Properties of Waves Pages By the end of section 4.1 you should be able to understand the following: Waves are disturbances that transmit energy from
More informationLecture Fundamentals of Data and signals
IT-5301-3 Data Communications and Computer Networks Lecture 05-07 Fundamentals of Data and signals Lecture 05 - Roadmap Analog and Digital Data Analog Signals, Digital Signals Periodic and Aperiodic Signals
More informationSupplementary Materials for
advances.sciencemag.org/cgi/content/full/4/2/e1700324/dc1 Supplementary Materials for Photocarrier generation from interlayer charge-transfer transitions in WS2-graphene heterostructures Long Yuan, Ting-Fung
More informationBioimaging of cells and tissues using accelerator-based sources
Analytical and Bioanalytical Chemistry Electronic Supplementary Material Bioimaging of cells and tissues using accelerator-based sources Cyril Petibois, Mariangela Cestelli Guidi Main features of Free
More informationSlide 1 / 99. Electromagnetic Waves
Slide 1 / 99 Electromagnetic Waves Slide 2 / 99 The Nature of Light: Wave or Particle The nature of light has been debated for thousands of years. In the 1600's, Newton argued that light was a stream of
More informationPhysics 1C. Lecture 24A. Finish Chapter 27: X-ray diffraction Start Chapter 24: EM waves. Average Quiz score = 6.8 out of 10.
Physics 1C Lecture 24A Finish Chapter 27: X-ray diffraction Start Chapter 24: EM waves Average Quiz score = 6.8 out of 10 This is a B- Diffraction of X-rays by Crystals! X-rays are electromagnetic radiation
More informationIntroduction to Telecommunications and Computer Engineering Unit 3: Communications Systems & Signals
Introduction to Telecommunications and Computer Engineering Unit 3: Communications Systems & Signals Syedur Rahman Lecturer, CSE Department North South University syedur.rahman@wolfson.oxon.org Acknowledgements
More informationWallace Hall Academy Physics Department. Waves. Pupil Notes Name:
Wallace Hall Academy Physics Department Waves Pupil Notes Name: Learning intentions for this unit? Be able to state that waves transfer energy. Be able to describe the difference between longitudinal and
More informationComputer Networks. Practice Set I. Dr. Hussein Al-Bahadili
بسم االله الرحمن الرحيم Computer Networks Practice Set I Dr. Hussein Al-Bahadili (1/11) Q. Circle the right answer. 1. Before data can be transmitted, they must be transformed to. (a) Periodic signals
More informationP6 Quick Revision Questions
P6 Quick Revision Questions H = Higher tier only SS = Separate science only Question 1... of 50 Define wavelength Answer 1... of 50 The distance from a point on one wave to the equivalent point on the
More informationAbsorption: in an OF, the loss of Optical power, resulting from conversion of that power into heat.
Absorption: in an OF, the loss of Optical power, resulting from conversion of that power into heat. Scattering: The changes in direction of light confined within an OF, occurring due to imperfection in
More informationThe ELI-ALPS project ELI: Extreme Light Infrastructure ALPS: Attosecond Light Pulse Source. Zsolt Fülöp
The ELI-ALPS project ELI: Extreme Light Infrastructure ALPS: Attosecond Light Pulse Source Zsolt Fülöp Landmark World s most advanced international laser research infrastructure Selected by ESFRI in 2006
More informationTSBB09 Image Sensors 2018-HT2. Image Formation Part 1
TSBB09 Image Sensors 2018-HT2 Image Formation Part 1 Basic physics Electromagnetic radiation consists of electromagnetic waves With energy That propagate through space The waves consist of transversal
More informationSTUDY OF APPLICATION OF THZ TIME DOMAIN SPECTROSCOPY IN FOOD SAFETY
STUDY OF APPLICATION OF THZ TIME DOMAIN SPECTROSCOPY IN FOOD SAFETY Liying Lang 1 *, Na Cai 2 1 Hebei University of Engineering, Handan, China, 056038; 2 College of Information and Electrical Engineering,
More informationMapping the Formation of Paper Products
Mapping the Formation of Paper Products Papiertechnische Stiftung (PTS) & Menlo Systems Authors: Patrizia Krok (Menlo Systems), Patrick Plew (PTS), Rafal Wilk (Menlo Systems) Introduction In the fabrication
More informationInstruction manual for T3DS software. Tool for THz Time-Domain Spectroscopy. Release 4.0
Instruction manual for T3DS software Release 4.0 Table of contents 0. Setup... 3 1. Start-up... 5 2. Input parameters and delay line control... 6 3. Slow scan measurement... 8 4. Fast scan measurement...
More informationTHE VERSATILE TERAHERTZ-SPECTROMETERS T-SPECTRALYZER. HÜBNER Photonics Coherence Matters.
THE VERSATILE TERAHERTZ-SPECTROMETERS T-SPECTRALYZER HÜBNER Photonics Coherence Matters. TERAHERTZ TECHNOLOGY VISUALIZING THE INVISIBLE Due to its non-invasive and non-ionizing properties, terahertz (THz)
More informationNAME SECTION PERFORMANCE TASK # 3. Part I. Qualitative Relationships
NAME SECTION PARTNERS DATE PERFORMANCE TASK # 3 You must work in teams of three or four (ask instructor) and will turn in ONE report. Answer all questions. Write in complete sentences. You must hand this
More informationUses of Electromagnetic Waves
Uses of Electromagnetic Waves 1 of 42 Boardworks Ltd 2016 Uses of Electromagnetic Waves 2 of 42 Boardworks Ltd 2016 What are radio waves? 3 of 42 Boardworks Ltd 2016 The broadcast of every radio and television
More information... frequency, f speed, v......
PhysicsAndMathsTutor.com 1 1. Define the terms wavelength, frequency and speed used to describe a progressive wave. wavelength, λ... frequency, f... speed, v... Hence derive the wave equation v = fλ which
More informationCONFIGURING. Your Spectroscopy System For PEAK PERFORMANCE. A guide to selecting the best Spectrometers, Sources, and Detectors for your application
CONFIGURING Your Spectroscopy System For PEAK PERFORMANCE A guide to selecting the best Spectrometers, s, and s for your application Spectral Measurement System Spectral Measurement System Spectrograph
More informationIntroductory Physics, High School Learning Standards for a Full First-Year Course
Introductory Physics, High School Learning Standards for a Full First-Year Course I. C ONTENT S TANDARDS 4.1 Describe the measurable properties of waves (velocity, frequency, wavelength, amplitude, period)
More informationA bluffer s guide to Radar
A bluffer s guide to Radar Andy French December 2009 We may produce at will, from a sending station, an electrical effect in any particular region of the globe; (with which) we may determine the relative
More informationOn the dielectric properties of substrates with different surface conditions for submillimeter-wave and terahertz applications
Invited Paper On the dielectric properties of substrates with different surface conditions for submillimeter-wave and terahertz applications Kung Bo Ng 1 and Chi Hou Chan 1*, 2 1 State Key Laboratory of
More informationApplication of maximum length sequences to photoacoustic chemical analysis
Application of maximum length sequences to photoacoustic chemical analysis Ralph T. Muehleisen and Arash Soleimani Civil, Architectural, and Environmental Engineering Illinois Institute of Technology,
More informationChemistry 524--"Hour Exam"--Keiderling Mar. 19, pm SES
Chemistry 524--"Hour Exam"--Keiderling Mar. 19, 2013 -- 2-4 pm -- 170 SES Please answer all questions in the answer book provided. Calculators, rulers, pens and pencils permitted. No open books allowed.
More informationLight has some interesting properties, many of which are used in medicine:
LIGHT IN MEDICINE Light has some interesting properties, many of which are used in medicine: 1- The speed of light changes when it goes from one material into another. The ratio of the speed of light in
More informationFOR 353: Air Photo Interpretation and Photogrammetry. Lecture 2. Electromagnetic Energy/Camera and Film characteristics
FOR 353: Air Photo Interpretation and Photogrammetry Lecture 2 Electromagnetic Energy/Camera and Film characteristics Lecture Outline Electromagnetic Radiation Theory Digital vs. Analog (i.e. film ) Systems
More informationDispersion properties of mid infrared optical materials
Dispersion properties of mid infrared optical materials Andrei Tokmakoff December 16 Contents 1) Dispersion calculations for ultrafast mid IR pulses ) Index of refraction of optical materials in the mid
More informationPHYSICS. Speed of Sound. Mr R Gopie
Speed of Sound Mr R Gopie a) Reciprocal firing Methods of determining the speed of sound in air include: Diag. 20 The time interval, t, between the flash and the sound represents the time taken for sound
More informationAIR-COUPLED PHOTOCONDUCTIVE ANTENNAS
AIR-COUPLED PHOTOCONDUCTIVE ANTENNAS Report: Air-Coupled Photoconductive Antennas In this paper, we present air-coupled terahertz photoconductive antenna (THz-PCAs) transmitters and receivers made on high-resistive
More informationSUPPLEMENTARY INFORMATION
SUPPLEMENTARY INFORMATION doi:10.1038/nature10864 1. Supplementary Methods The three QW samples on which data are reported in the Letter (15 nm) 19 and supplementary materials (18 and 22 nm) 23 were grown
More informationImaging with terahertz waves
1716 OPTICS LETTERS / Vol. 20, No. 16 / August 15, 1995 Imaging with terahertz waves B. B. Hu and M. C. Nuss AT&T Bell Laboratories, 101 Crawfords Corner Road, Holmdel, New Jersey 07733-3030 Received May
More informationLaser Locking with Doppler-free Saturated Absorption Spectroscopy
Laser Locking with Doppler-free Saturated Absorption Spectroscopy Paul L. Stubbs, Advisor: Irina Novikova W&M Quantum Optics Group May 12, 2010 Abstract The goal of this project was to lock the frequency
More informationWave Behavior and The electromagnetic Spectrum
Wave Behavior and The electromagnetic Spectrum What is Light? We call light Electromagnetic Radiation. Or EM for short It s composed of both an electrical wave and a magnetic wave. Wave or particle? Just
More informationTesting with Femtosecond Pulses
Testing with Femtosecond Pulses White Paper PN 200-0200-00 Revision 1.3 January 2009 Calmar Laser, Inc www.calmarlaser.com Overview Calmar s femtosecond laser sources are passively mode-locked fiber lasers.
More informationΕισαγωγική στην Οπτική Απεικόνιση
Εισαγωγική στην Οπτική Απεικόνιση Δημήτριος Τζεράνης, Ph.D. Εμβιομηχανική και Βιοϊατρική Τεχνολογία Τμήμα Μηχανολόγων Μηχανικών Ε.Μ.Π. Χειμερινό Εξάμηνο 2015 Light: A type of EM Radiation EM radiation:
More informationTAPPI Extrusion Coating Short Course 2010 Charleston, SC
Welcome... Please remember that this session is to be held in strict compliance with the TAPPI Antitrust Policy. Specifically, discussing prices or pricing policy and discussing any restraint on competition
More information레이저의주파수안정화방법및그응용 박상언 ( 한국표준과학연구원, 길이시간센터 )
레이저의주파수안정화방법및그응용 박상언 ( 한국표준과학연구원, 길이시간센터 ) Contents Frequency references Frequency locking methods Basic principle of loop filter Example of lock box circuits Quantifying frequency stability Applications
More informationExperimental Physics. Experiment C & D: Pulsed Laser & Dye Laser. Course: FY12. Project: The Pulsed Laser. Done by: Wael Al-Assadi & Irvin Mangwiza
Experiment C & D: Course: FY1 The Pulsed Laser Done by: Wael Al-Assadi Mangwiza 8/1/ Wael Al Assadi Mangwiza Experiment C & D : Introduction: Course: FY1 Rev. 35. Page: of 16 1// In this experiment we
More informationChapter 21. Alternating Current Circuits and Electromagnetic Waves
Chapter 21 Alternating Current Circuits and Electromagnetic Waves AC Circuit An AC circuit consists of a combination of circuit elements and an AC generator or source The output of an AC generator is sinusoidal
More informationTerahertz Spectral Range
Inhalt 1. Einleitung 2. Wechselwirkung Licht-Materie 3. Bilanzgleichungen 4. Kontinuierlicher Betrieb 5. Relaxationsoszillationen 6. Güteschaltung 7. Modenkopplung 8. Laserresonatoren 9. Eigenschaften
More informationTheoretical Approach. Why do we need ultra short technology?? INTRODUCTION:
Theoretical Approach Why do we need ultra short technology?? INTRODUCTION: Generating ultrashort laser pulses that last a few femtoseconds is a highly active area of research that is finding applications
More informationOPTICAL SENSORS-CONSTRUCTION ALTERNATIVES
OPTICAL SENSORS-CONSTRUCTION ALTERNATIVES Mariana ENACHE, Cristina ŢUINEA BOBE Universitatea Valahia Târgovişte, Facultatea Ştiinta si Ingineria Materialelor, B-dul Regele Carol I, Nr.2, 0200, Târgovişte,
More informationLight sources can be natural or artificial (man-made)
Light The Sun is our major source of light Light sources can be natural or artificial (man-made) People and insects do not see the same type of light - people see visible light - insects see ultraviolet
More informationTerm Info Picture. A wave that has both electric and magnetic fields. They travel through empty space (a vacuum).
Waves S8P4. Obtain, evaluate, and communicate information to support the claim that electromagnetic (light) waves behave differently than mechanical (sound) waves. A. Ask questions to develop explanations
More informationAn EPR Primer 2. Basic EPR Theory 2.1. Introduction to Spectroscopy 2.1.1
An EPR Primer 2 This chapter is an introduction to the basic theory and practice of EPR spectroscopy. It gives you sufficient background to understand the following chapters. In addition, we strongly encourage
More information$100 $400 $400 $400 $500
$100 $100 $100 $100 $100 $200 $200 $200 $200 $200 $300 $300 $300 $300 $300 $400 $400 $400 $400 $400 $500 $500 $500 $500 $500 MOVING IN WAVES PURE ENERGY! WHAT S THE FREQUENCY, KENNETH? USE IT OR LOSE IT
More informationOptical Gain Experiment Manual
Optical Gain Experiment Manual Table of Contents Purpose 1 Scope 1 1. Background Theory 1 1.1 Absorption, Spontaneous Emission and Stimulated Emission... 2 1.2 Direct and Indirect Semiconductors... 3 1.3
More informationEstimation of cross coupling of receiver noise between the EoR fat-dipole antennas
Estimation of cross coupling of receiver noise between the EoR fat-dipole antennas Due to the proximity of the fat dipoles in the EoR receiver configuration, the receiver noise of individual antennas may
More informationFiber Optic Communications Communication Systems
INTRODUCTION TO FIBER-OPTIC COMMUNICATIONS A fiber-optic system is similar to the copper wire system in many respects. The difference is that fiber-optics use light pulses to transmit information down
More informationPB T/R Two-Channel Portable Frequency Domain Terahertz Spectrometer
Compact, Portable Terahertz Spectroscopy System Bakman Technologies versatile PB7220-2000-T/R Spectroscopy Platform is designed for scanning complex compounds to precise specifications with greater accuracy
More informationDraw and label this wave: - What do waves transfer? (They do this without transferring what?) What do all electromagnetic waves have in common?
What do waves transfer? Draw and label this wave: - (They do this without transferring what?) What do all electromagnetic waves have in common? Name the electromagnetic spectrum from shortest to longest
More information2. Pulsed Acoustic Microscopy and Picosecond Ultrasonics
1st International Symposium on Laser Ultrasonics: Science, Technology and Applications July 16-18 2008, Montreal, Canada Picosecond Ultrasonic Microscopy of Semiconductor Nanostructures Thomas J GRIMSLEY
More informationAP Chemistry Cell Phone Spectroscopy Lab Adopted from Alexander Scheeline Department of Chemistry University of Illinois at Urbana-Champaign
AP Chemistry Cell Phone Spectroscopy Lab Adopted from Alexander Scheeline Department of Chemistry University of Illinois at Urbana-Champaign Back Ground Electromagnetic radiation Electromagnetic radiation
More informationNote 2 Electromagnetic waves N2/EMWAVES/PHY/XII/CHS2012
ELECTROMAGNETIC SPECTRUM Electromagnetic waves include visible light waves, X-rays, gamma rays, radio waves, microwaves, ultraviolet and infrared waves. The classification of em waves according to frequency
More informationExperiment 19. Microwave Optics 1
Experiment 19 Microwave Optics 1 1. Introduction Optical phenomena may be studied at microwave frequencies. Using a three centimeter microwave wavelength transforms the scale of the experiment. Microns
More informationMass Spectrometry and the Modern Digitizer
Mass Spectrometry and the Modern Digitizer The scientific field of Mass Spectrometry (MS) has been under constant research and development for over a hundred years, ever since scientists discovered that
More informationDetection of the mm-wave radiation using a low-cost LWIR microbolometer camera from a multiplied Schottky diode based source
Detection of the mm-wave radiation using a low-cost LWIR microbolometer camera from a multiplied Schottky diode based source Basak Kebapci 1, Firat Tankut 2, Hakan Altan 3, and Tayfun Akin 1,2,4 1 METU-MEMS
More informationPB T/R Two-Channel Portable Frequency Domain Terahertz Spectrometer
PB7220-2000-T/R Two-Channel Portable Frequency DATASHEET MA 2015 Compact, Portable Terahertz Spectroscopy System Bakman Technologies versatile PB7220-2000-T/R Spectroscopy Platform is designed for scanning
More informationHigh frequency sounds, beyond the range of human hearing, are called ultrasound.
Mr Downie 2014 1 Sound Waves To produce a sound the particles in an object must vibrate. This means that sound can travel through solids, liquids and gases. Sound cannot travel through a vacuum as it contains
More informationLECTURE 20 ELECTROMAGNETIC WAVES. Instructor: Kazumi Tolich
LECTURE 20 ELECTROMAGNETIC WAVES Instructor: Kazumi Tolich Lecture 20 2 25.6 The photon model of electromagnetic waves 25.7 The electromagnetic spectrum Radio waves and microwaves Infrared, visible light,
More informationThermal tuning of volume Bragg gratings for high power spectral beam combining
Thermal tuning of volume Bragg gratings for high power spectral beam combining Derrek R. Drachenberg, Oleksiy Andrusyak, Ion Cohanoschi, Ivan Divliansky, Oleksiy Mokhun, Alexei Podvyaznyy, Vadim Smirnov,
More informationHARDWARE IMPLEMENTATION OF LOCK-IN AMPLIFIER FOR NOISY SIGNALS
Integrated Journal of Engineering Research and Technology HARDWARE IMPLEMENTATION OF LOCK-IN AMPLIFIER FOR NOISY SIGNALS Prachee P. Dhapte, Shriyash V. Gadve Department of Electronics and Telecommunication
More informationECE 340 Lecture 29 : LEDs and Lasers Class Outline:
ECE 340 Lecture 29 : LEDs and Lasers Class Outline: Light Emitting Diodes Lasers Semiconductor Lasers Things you should know when you leave Key Questions What is an LED and how does it work? How does a
More information