• Scattering Is a General Physical Process Where Some Forms of Radiation, Such As Light, Sound, Or Moving Particles, Are Forced to Deviate from a Straight Trajectory‘
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Brillouin Scattering in Photonic Crystal Fiber : from Fundamentals to Fiber Optic Sensors Birgit Stiller
Brillouin scattering in photonic crystal fiber : from fundamentals to fiber optic sensors Birgit Stiller To cite this version: Birgit Stiller. Brillouin scattering in photonic crystal fiber : from fundamentals to fiber optic sensors. Other. Université de Franche-Comté, 2011. English. NNT : 2011BESA2019. tel-00839263 HAL Id: tel-00839263 https://tel.archives-ouvertes.fr/tel-00839263 Submitted on 27 Jun 2013 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Universit´ede Franche-Comt´e E´cole Doctorale SPIM Th`ese de Doctorat Sp´ecialit´eOptique Photonique pr´esent´ee par Birgit Stiller Brillouin scattering in photonic crystal fiber: from fundamentals to fiber optic sensors Th`ese dirig´ee par T. Sylvestre et H. Maillotte soutenue le 12 d´ecembre 2011 Jury : Rapporteurs : Prof. Gerd LEUCHS, Universit´eErlangen-Nuremberg, Allemagne Prof. Luc THEVENAZ, Ecole Polytechnique F´ed´erale de Lausanne, Suisse Examinateurs : Dr. Francesco POLETTI, Universit´ede Southampton, Royaume-Uni Dr. Alexandre KUDLINSKI, Universit´eLille 1, France Prof. John M. DUDLEY, Universit´ede Franche-Comt´e, France Dr. Vincent LAUDE, Directeur de Recherche CNRS, France Dr. Thibaut SYLVESTRE, Charg´ede Recherche CNRS, France Dr. Herv´eMAILLOTTE, Directeur de Recherche CNRS, France Invit´e: Dr. -
Raman Scattering and Fluorescence
Fluorescence 01 Raman Scattering and Fluorescence Introduction The existence of such virtual states also explains why the non-resonance Raman effect Raman scattering and Fluorescence emission does not depend on the wavelength of the are two competing phenomena, which have excitation, since no real states are involved in similar origins. Generally, a laser photon this interaction mechanism. In fact, the Raman bounces off a molecule and looses a certain spectrum generally does not depend on the amount of energy that allows the molecule to laser excitation. vibrate (Stokes process). The scattered photon is therefore less energetic and the associated However, when the energy of the excitation light exhibits a frequency shift. The various photon gets close to the transition energy frequency shifts associated with different between two electronic states, one then deals molecular vibrations give rise to a spectrum, with resonance Raman or resonance that is characteristic of a specific compound. fluorescence (fig.1, case (d)). The basic difference between these two processes is In contrast, fluorescence or luminescence related to the time scales involved, as well as emission follows an absorption process. For a with the nature of the so-called intermediate better understanding, one can refer to the states. In contrast with resonant fluorescent, diagram below. relaxed fluorescence results from the emission of a photon from the lowest vibrational level of an excited electronic state, following a direct absorption of the photon and relaxation of the molecule from its vibrationally excited level of the electronic state back to the lowest vibrational level of the electronic state. A fluorescence process typically requires more than 10-9 s. -
Elastic Characterization of Transparent and Opaque Films, Multilayers and Acoustic Resonators by Surface Brillouin Scattering: a Review
applied sciences Article Elastic Characterization of Transparent and Opaque Films, Multilayers and Acoustic Resonators by Surface Brillouin Scattering: A Review Giovanni Carlotti ID Dipartimento di Fisica e Geologia, Università di Perugia, 06123 Perugia, Italy; [email protected]; Tel.: +39-0755-852-767 Received: 17 December 2017; Accepted: 5 January 2018; Published: 16 January 2018 Abstract: There is currently a renewed interest in the development of experimental methods to achieve the elastic characterization of thin films, multilayers and acoustic resonators operating in the GHz range of frequencies. The potentialities of surface Brillouin light scattering (surf-BLS) for this aim are reviewed in this paper, addressing the various situations that may occur for the different types of structures. In particular, the experimental methodology and the amount of information that can be obtained depending on the transparency or opacity of the film material, as well as on the ratio between the film thickness and the light wavelength, are discussed. A generalization to the case of multilayered samples is also provided, together with an outlook on the capability of the recently developed micro-focused scanning version of the surf-BLS technique, which opens new opportunities for the imaging of the spatial profile of the acoustic field in acoustic resonators and in artificially patterned metamaterials, such as phononic crystals. Keywords: acousto-optics at the micro- and nanoscale; photon scattering by phonons; elastic constants of films and multilayers 1. Introduction The problem of a detailed knowledge of the elastic constants of thin film materials has attracted much attention in recent years, because of the growing importance of single- and multi-layered structures in advanced applications such as in devices for information and communication technology (ICT). -
Recent Progress in Distributed Brillouin Sensors Based on Few-Mode Optical Fibers
sensors Review Recent Progress in Distributed Brillouin Sensors Based on Few-Mode Optical Fibers Yong Hyun Kim and Kwang Yong Song * Department of Physics, Chung-Ang University, Seoul 06974, Korea; [email protected] * Correspondence: [email protected]; Tel.: +82-2-820-5834 Abstract: Brillouin scattering is a dominant inelastic scattering observed in optical fibers, where the energy and momentum transfer between photons and acoustic phonons takes place. Narrowband reflection (or gain and loss) spectra appear in the spontaneous (or stimulated) Brillouin scattering, and their linear dependence of the spectral shift on ambient temperature and strain variations is the operation principle of distributed Brillouin sensors, which have been developed for several decades. In few-mode optical fibers (FMF’s) where higher-order spatial modes are guided in addition to the fundamental mode, two different optical modes can be coupled by the process of stimulated Brillouin scattering (SBS), as observed in the phenomena called intermodal SBS (two photons + one acoustic phonon) and intermodal Brillouin dynamic grating (four photons + one acoustic phonon; BDG). These intermodal scattering processes show unique reflection (or gain and loss) spectra depending on the spatial mode structure of FMF, which are useful not only for the direct measurement of polarization and modal birefringence in the fiber, but also for the measurement of environmental variables like strain, temperature, and pressure affecting the birefringence. In this paper, we present a technical review on recent development of distributed Brillouin sensors on the platform of FMF’s. Keywords: few-mode fiber; fiber optic sensors; Brillouin scattering; distributed measurement Citation: Kim, Y.H.; Song, K.Y. -
Stimulated Brillouin Scattering in Nanoscale Silicon Step-Index Waveguides: a General Framework of Selection Rules and Calculating SBS Gain
Stimulated Brillouin scattering in nanoscale silicon step-index waveguides: a general framework of selection rules and calculating SBS gain Wenjun Qiu,1 Peter T. Rakich,2 Heedeuk Shin,2 Hui Dong,3 Marin Soljaciˇ c,´ 1 and Zheng Wang3;∗ 1Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 USA 2Department of Applied Physics, Yale University, New Haven, CT 06520 USA 3Department of Electrical and Computer Engineering, University of Texas at Austin, Austin, TX 78758 USA ∗[email protected] Abstract: We develop a general framework of evaluating the Stimulated Brillouin Scattering (SBS) gain coefficient in optical waveguides via the overlap integral between optical and elastic eigen-modes. This full-vectorial formulation of SBS coupling rigorously accounts for the effects of both radiation pressure and electrostriction within micro- and nano-scale waveg- uides. We show that both contributions play a critical role in SBS coupling as modal confinement approaches the sub-wavelength scale. Through analysis of each contribution to the optical force, we show that spatial symmetry of the optical force dictates the selection rules of the excitable elastic modes. By applying this method to a rectangular silicon waveguide, we demonstrate how the optical force distribution and elastic modal profiles jointly determine the magnitude and scaling of SBS gains in both forward and backward SBS processes. We further apply this method to the study of intra- and inter-modal SBS processes, and demonstrate that the coupling between distinct optical modes are necessary to excite elastic modes with all possible symmetries. For example, we show that strong inter-polarization coupling can be achieved between the fundamental TE- and TM-like modes of a suspended silicon waveguide. -
Article Intends to Provide a for the Necessary Virtual Electronic Brief Overview of the Differences and Transition
ADVANCES IN RAMAN TECHNIQUES Laser requirements and advances for Raman techniques Andreas Isemann Laser Quantum GmbH, 78467 Konstanz, Germany INTRODUCTION 473 nm and 1064 nm, a narrow Raman scattering as a probe of bandwidth output of few tens of GHz vibrational transitions has made or below 1 MHz if needed within the leaps and bounds since its discovery, linewidth of vibrational transitions and various schemes based on this for high resolution, low noise (less phenomenon have been developed than 0.02%) and excellent beam with great success. quality (fundamental transversal Applications range from basic electromagnetic mode TEM00) scientific research, to medical and provides optimised performance industrial instrumentation. Some for the resolution of the Raman schemes utilise linear Raman measurement needed. scattering, whilst others take advantage The wavelength is chosen based of high peak-power fields to probe on the sample under investigation, nonlinear Raman responses. with 532 nm being commonly used This article intends to provide a for the necessary virtual electronic brief overview of the differences and transition. In the following section, benefits, together with the laser source four examples from different areas of requirements and the advancements Raman applications show the diverse in techniques enabled by recent applications of linear Raman and what developments in lasers. advances have been achieved. An example of studying a real-world LINEAR RAMAN application, the successful control of Figure 1 An example of the RR microfluidic device counting of The advent of the laser in providing a food quality using Raman spectroscopy photosynthetic microorganisms. As the cells of the model strain high-intensity coherent light source and multivariate analysis, is described Synechocystis sp. -
Interaction of Light with Materials
Module 2 - Interaction of Light with Materials Silvia Kolchens Faculty for Chemistry, Pima Community College Silvia Kolchens is instructional faculty for chemistry at Pima Community College, Tucson, Arizona since 1995. Her regular teaching responsibilities include general chemistry, organic chemistry and more recently solid-state chemistry. She received her PhD in physical chemistry from the University of Cologne, Germany, and did postdoctoral work at the University of Arizona. Her professional interests include the development of case studies in environmental chemistry and computer applications in chemistry to engage students actively in learning through inquiry based instruction and visual representations of complex phenomena. Outside the classroom she enjoys exploring the world through hiking, photography, and motorcycling. Email: [email protected] 1 Introduction Do you ever wonder what happens to light when it hits a material? Why do some objects appear transparent or opaque, clear or colored? What happens to an electromagnetic wave when it interacts with a particle? Why is this important and why should we care? We care because it is the interaction of light and materials that enables us to see light and guide it. Understanding the principles of light and material interactions enables us to observe and manipulate our environment. Figure 1 Sunset - Wasson Peak, Tucson, Arizona; Photo by S. Kolchens The authors would like to acknowledge support from the National Science Foundation through CIAN NSF ERC 1 under grant #EEC-0812072 1.1 The Field of Optics Optics is a science that deals with the genesis and propagation of light in the in all ranges of the electromagnetic spectrum and is an engineering discipline that uses materials and optical principles to build optical instruments. -
Suppression of Stimulated Brillouin Scattering in Optical Fibers Using a Linearly Chirped Diode Laser
Suppression of stimulated Brillouin scattering in optical fibers using a linearly chirped diode laser J. O. White,1,* A. Vasilyev,2 J. P. Cahill,1 N. Satyan,2 O. Okusaga,1 G. Rakuljic,3 C. E. Mungan,4 and A. Yariv2 1 U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland 20783, USA 2Department of Applied Physics and Materials Science, California Institute of Technology, 1200 E. California Blvd. 136-93, Pasadena, California 91125, USA 3 Telaris, Inc., 2118 Wilshire Blvd. #238, Santa Monica, California 90403, USA 4 Physics Department, U.S. Naval Academy, Annapolis, Maryland 21402, USA *[email protected] Abstract: The output of high power fiber amplifiers is typically limited by stimulated Brillouin scattering (SBS). An analysis of SBS with a chirped pump laser indicates that a chirp of 2.5 × 1015 Hz/s could raise, by an order of magnitude, the SBS threshold of a 20-m fiber. A diode laser with a constant output power and a linear chirp of 5 × 1015 Hz/s has been previously demonstrated. In a low-power proof-of-concept experiment, the threshold for SBS in a 6-km fiber is increased by a factor of 100 with a chirp of 5 × 1014 Hz/s. A linear chirp will enable straightforward coherent combination of multiple fiber amplifiers, with electronic compensation of path length differences on the order of 0.2 m. ©2012 Optical Society of America OCIS codes: (060.2320) Fiber optics amplifiers and oscillators; (190.5890) Scattering, stimulated; (140.3518) Lasers, frequency modulated. References and links 1. -
High Performance Raman Spectroscopy with Simple Optical Components ͒ ͒ W
High performance Raman spectroscopy with simple optical components ͒ ͒ W. R. C. Somerville, E. C. Le Ru,a P. T. Northcote, and P. G. Etchegoinb The MacDiarmid Institute for Advanced Materials and Nanotechnology, School of Chemical and Physical Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand ͑Received 6 December 2009; accepted 19 April 2010͒ Several simple experimental setups for the observation of Raman scattering in liquids and gases are described. Typically these setups do not involve more than a small ͑portable͒ CCD-based spectrometer ͑without scanning͒, two lenses, and a portable laser. A few extensions include an inexpensive beam-splitter and a color filter. We avoid the use of notch filters in all of the setups. These systems represent some of the simplest but state-of-the-art Raman spectrometers for teaching/ demonstration purposes and produce high quality data in a variety of situations; some of them traditionally considered challenging ͑for example, the simultaneous detection of Stokes/anti-Stokes spectra or Raman scattering from gases͒. We show examples of data obtained with these setups and highlight their value for understanding Raman spectroscopy. We also provide an intuitive and nonmathematical introduction to Raman spectroscopy to motivate the experimental findings. © 2010 American Association of Physics Teachers. ͓DOI: 10.1119/1.3427413͔ I. INTRODUCTION and finish with a higher energy than the original one. This case corresponds to anti-Stokes Raman scattering. The Raman effect was discovered in 1928 by Raman1 and In reality, the photon is usually provided by a laser, which is now a major research tool with applications in physics, has a well defined frequency. -
Stimulated Brillouin Backscattering for Laser-Plasma Interaction in the Strong Coupling Regime
Stimulated Brillouin Backscattering For Laser-Plasma Interaction In The Strong Coupling Regime S. Weber1;2;3;?, C. Riconda1;2, V.T. Tikhonchuk1 1Centre Lasers Intenses et Applications, UMR 5107 CNRS-Universit´e Bordeaux 1-CEA, Universit´e Bordeaux 1, 33405 Talence, France 2Laboratoire pour l'Utilisation Lasers Intenses/Physique Atomique des Plasmas Denses, UMR 7605 CNRS-CEA-Ecole Polytechnique-Universit´e Paris VI, Universit´e Paris VI, 75252 Paris, France 3 Centre de Physique Th´eorique, UMR 7644 CNRS-Ecole Polytechnique, Ecole Polytechnique, 91128 Palaiseau, France ? email: [email protected] The strong coupling (sc) regime of stimulated Brillouin backscattering (SBS) is characterized by relatively high laser intensities and low electron temperatures. In this regime of laser plasma interaction (LPI) the pump wave determines the properties of the electrostatic wave. The present contribution intends to present several aspects of this regime. Up to now sc-SBS has received little attention due to the fact that research on LPI was dominated by standard inertial confinement fusion (ICF) relevant parameters. However, sc-SBS has several interesting applications and might also open up new approaches to ICF. One application is plasma-based optical parametric amplification (POPA) which allows for the creation of short and intense laser pulses. POPA has several advantages with respect to other approaches, such as Raman-based amplification, and overcomes damage threshold limitations of standard OPA using optical materials. Recent experiments are approaching the sc-regime even for short laser wavelengths. Simula- tions operating above the quarter-critical density have shown that new modes (e.g. KEENs, electron- acoustic modes, solitons etc.) can be excited which couple to the usual plasma modes and provide new decay channels for SBS. -
L23 Stimulated Raman Scattering. Stimulated Brillouin Scattering
Lecture 23 Stimulated Raman scattering, Stokes and anti-Stokes waves. Stimulated Brillouin scattering. 1 1 Stimulated Raman scattering (SRS) 2 2 1 Stimulated Raman scattering (SRS) We will see now how energy dissipation can lead to both field attenuation and field amplification. 3 3 Stimulated Raman scattering (SRS) Molecule: vibrates at freq. Ω Ω ω ω ω±Ω sidebands ±Ω 4 4 2 Stimulated Raman scattering (SRS) Total field squared time averaged: 2 Back action [E1cos(ωt) +E2cos(ω–Ω)] Ω ω ω–Ω time This modulated intensity coherently excites the molecular oscillation at frequency ωL − ωS = Ω. 5 5 Stimulated Raman scattering (SRS) Back action ω q - normal coordinte Dipole moment of a molecule: � = �$�� ω–Ω key assumption of the theory: �� � = � + � $ �� Energy due the oscillating field E: 1 � = � ��- 2 $ Two laser frequencies force molecule to vibrate at freq. Ω The applied optical field exerts a force �� 1 �� � = = � �- �� 2 $ �� 6 6 3 Stimulated Raman scattering (SRS) 4 total field ℰ(�) = ( � �7(89:;<9=) + � �7(8?:;<?=) + �. �.) - 5 > force term oscilalting at Ω is: 1 �� 1 1 �� � �, � = � 2( � �∗�7(J:;K=) + �. �. ) = � ( � �∗�7(J:;K=) + �. �. ) 2 $ �� 4 5 > 4 $ �� 5 > Simple oscillator model for molecular motion. � � 1 �� �̈ + ��̇ + Ω-� = = � ( � �∗�7(J:;K=) + �. �. ) $ � 4� $ �� 5 > 4 look for q in the form � = [�(Ω)�7(J:;K=) + �. �. ] - we thus find that the amplitude of the molecular vibration is given by ∗ 1 �� �5�> �(Ω) = �$ - - 2� �� Ω$ − Ω + ��� 7 7 Stimulated Raman scattering (SRS) YZ NL polarization � �, � = �� �, � = �� �(�, �)� z, t = � �(� + �)� �, � $ $ $ Y[ the nonlinear part of the polarization is given by �� 1 1 � �, � = � � [�(Ω)�7(J:;K=) + �. �. ] ( � �7(89:;<9=) + � �7(8?:;<?=) + �. -
Spontaneous Brillouin Scattering Spectrum and Coherent Brillouin Gain in Optical Fibers Vincent Laude, Jean-Charles Beugnot
Spontaneous Brillouin scattering spectrum and coherent Brillouin gain in optical fibers Vincent Laude, Jean-Charles Beugnot To cite this version: Vincent Laude, Jean-Charles Beugnot. Spontaneous Brillouin scattering spectrum and coherent Bril- louin gain in optical fibers. Applied Sciences, MDPI, 2018, 8, pp.907 (10). hal-02131441 HAL Id: hal-02131441 https://hal.archives-ouvertes.fr/hal-02131441 Submitted on 16 May 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. applied sciences Article Spontaneous Brillouin Scattering Spectrum and Coherent Brillouin Gain in Optical Fibers Vincent Laude * ID and Jean-Charles Beugnot ID Institut FEMTO-ST, Université Bourgogne Franche-Comté, CNRS, 25030 Besançon, France; [email protected] * Correspondence: [email protected]; Tel.: +33-363-082-457 Received: 28 February 2018; Accepted: 30 May 2018; Published: 1 June 2018 Abstract: Brillouin light scattering describes the diffraction of light waves by acoustic phonons, originating from random thermal fluctuations inside a transparent body, or by coherent acoustic waves, generated by a transducer or from the interference of two frequency-detuned optical waves. In experiments with optical fibers, it is generally found that the spontaneous Brillouin spectrum has the same frequency dependence as the coherent Brillouin gain.