Principles of Retarders
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USOO5926295A United States Patent (19) 11 Patent Number: 5,926,295 Charlot et al. (45) Date of Patent: Jul. 20, 1999 54) HOLOGRAPHIC PROCESS AND DEVICE 4,602,844 7/1986 Sirat et al. ............................. 350/3.83 USING INCOHERENT LIGHT 4,976,504 12/1990 Sirat et al. .. ... 350/3.73 5,011,280 4/1991 Hung.............. ... 356/345 75 Inventors: Didier Charlot, Paris; Yann Malet, 5,081,540 1/1992 Dufresne et al. ... ... 359/30 Saint Cyr l’Ecole, both of France 5,081,541 1/1992 Sirat et al. ...... ... 359/30 5,216,527 6/1993 Sharnoff et al. ... 359/10 73 Assignee: Le Conoscope SA, Paris, France 5,223,966 6/1993 Tomita et al. .......................... 359/108 5,291.314 3/1994 Agranat et al. ......................... 359/100 21 Appl. No.: 08/681,926 22 Filed: Jul. 29, 1996 Primary Examiner Jon W. Henry Attorney, Agent, or Firm Michaelson & Wallace; Peter L. Related U.S. Application Data Michaelson; John C. Pokotylo 62 Division of application No. 08/244.249, filed as application 57 ABSTRACT No. PCT/FR92/01095, Nov. 25, 1992, Pat. No. 5,541,744. An optical device for generating a signal based on a distance 30 Foreign Application Priority Data of an object from the optical device. The optical device includes a first polarizer, a birefringent crystal positioned Nov. 27, 1991 FR France ................................... 91. 14661 optically downstream from the first polarizer, and a Second 51) Int. Cl. .............................. G03H 1/26; G01B 9/021 polarizer arranged optically downstream from the birefrin 52 U.S. Cl. ................................... 359/30; 359/11; 359/1; gent crystal. -
Lab 8: Polarization of Light
Lab 8: Polarization of Light 1 Introduction Refer to Appendix D for photos of the appara- tus Polarization is a fundamental property of light and a very important concept of physical optics. Not all sources of light are polarized; for instance, light from an ordinary light bulb is not polarized. In addition to unpolarized light, there is partially polarized light and totally polarized light. Light from a rainbow, reflected sunlight, and coherent laser light are examples of po- larized light. There are three di®erent types of po- larization states: linear, circular and elliptical. Each of these commonly encountered states is characterized Figure 1: (a)Oscillation of E vector, (b)An electromagnetic by a di®ering motion of the electric ¯eld vector with ¯eld. respect to the direction of propagation of the light wave. It is useful to be able to di®erentiate between 2 Background the di®erent types of polarization. Some common de- vices for measuring polarization are linear polarizers and retarders. Polaroid sunglasses are examples of po- Light is a transverse electromagnetic wave. Its prop- larizers. They block certain radiations such as glare agation can therefore be explained by recalling the from reflected sunlight. Polarizers are useful in ob- properties of transverse waves. Picture a transverse taining and analyzing linear polarization. Retarders wave as traced by a point that oscillates sinusoidally (also called wave plates) can alter the type of polar- in a plane, such that the direction of oscillation is ization and/or rotate its direction. They are used in perpendicular to the direction of propagation of the controlling and analyzing polarization states. -
Static and Dynamic Effects of Chirality in Dielectric Media
Static and dynamic effects of chirality in dielectric media R. S. Lakes Department of Engineering Physics, Department of Materials Science, University of Wisconsin, 1500 Engineering Drive, Madison, WI 53706-1687 [email protected] January 31, 2017 adapted from R. S. Lakes, Modern Physics Letters B, 30 (24) 1650319 (9 pages) (2016). Abstract Chiral dielectrics are considered from the perspective of continuum representations of spatial heterogeneity. Static effects in isotropic chiral dielectrics are predicted, provided the electric field has nonzero third spatial derivatives. The effects are compared with static chiral phenomena in Cosserat elastic materials which obey generalized continuum constitutive equations. Dynamic monopole - like magnetic induction is predicted in chiral dielectric media. keywords: chirality, dielectric, Cosserat 1 Introduction Chirality is well known in electromagnetics 1; it gives rise to optical activity in which left or right handed cir- cularly polarized waves propagate at different velocities. Known effects are dynamic only; there is considered to be no static effect 2. The constitutive equations for a directionally isotropic chiral material are 3, 4. @H D = kE − g (1) @t @E B = µH + g (2) @t in which E is electric field, D is electric displacement, B is magnetic field, H is magnetic induction, k is the dielectric permittivity, µ is magnetic permeability and g is a measure of the chirality. Optical rotation of polarized light of wavelength λ by an angle Φ (in radians per meter) is given by Φ = (2π/λ)2cg with c as the speed of light. The quantity g embodies the length scale of the chiral structure because cg has dimensions of length. -
Circular Polarization and Nonreciprocal Propagation in Magnetic Media Circular Polarization and Nonreciprocal Propagation in Magnetic Media Gerald F
• DIONNE, ALLEN, Haddad, ROSS, AND LaX Circular Polarization and Nonreciprocal Propagation in Magnetic Media Circular Polarization and Nonreciprocal Propagation in Magnetic Media Gerald F. Dionne, Gary A. Allen, Pamela R. Haddad, Caroline A. Ross, and Benjamin Lax n The polarization of electromagnetic signals is an important feature in the design of modern radar and telecommunications. Standard electromagnetic theory readily shows that a linearly polarized plane wave propagating in free space consists of two equal but counter-rotating components of circular polarization. In magnetized media, these circular modes can be arranged to produce the nonreciprocal propagation effects that are the basic properties of isolator and circulator devices. Independent phase control of right-hand (+) and left-hand (–) circular waves is accomplished by splitting their propagation velocities through differences in the e±m± parameter. A phenomenological analysis of the permeability m and permittivity e in dispersive media serves to introduce the corresponding magnetic- and electric-dipole mechanisms of interaction length with the propagating signal. As an example of permeability dispersion, a Lincoln Laboratory quasi-optical Faraday- rotation isolator circulator at 35 GHz (l ~ 1 cm) with a garnet-ferrite rotator element is described. At infrared wavelengths (l = 1.55 mm), where fiber-optic laser sources also require protection by passive isolation of the Faraday-rotation principle, e rather than m provides the dispersion, and the frequency is limited to the quantum energies of the electric-dipole atomic transitions peculiar to the molecular structure of the magnetic garnet. For optimum performance, bismuth additions to the garnet chemical formula are usually necessary. Spectroscopic and molecular theory models developed at Lincoln Laboratory to explain the bismuth effects are reviewed. -
Optical and Thin Film Physics Polarisation of Light
OPTICAL AND THIN FILM PHYSICS POLARISATION OF LIGHT An electromagnetic wave such as light consists of a coupled oscillating electric field and magnetic field which are always perpendicular to each other; by convention, the "polarization" of electromagnetic waves refers to the direction of the electric field. In linear polarization, the fields oscillate in a single direction. In circular or elliptical polarization, the fields rotate at a constant rate in a plane as the wave travels. The rotation can have two possible directions; if the fields rotate in a right hand sense with respect to the direction of wave travel, it is called right circular polarization, while if the fields rotate in a left hand sense, it is called left circular polarization. On the other side of the plate, examine the wave at a point where the fast-polarized component is at maximum. At this point, the slow-polarized component will be passing through zero, since it has been retarded by a quarter-wave or 90° in phase. Moving an eighth wavelength farther, we will note that the two are the same magnitude, but the fast component is decreasing and the slow component is increasing. Moving another eighth wave, we find the slow component is at maximum and the fast component is zero. If the tip of the total electric vector is traced, we find it traces out a helix, with a period of just one wavelength. This describes circularly polarized light. Left-hand polarized light is produced by rotating either the waveplate or the plane of polarization of the incident light 90° . -
Stokes Polarimetry
photoelastic modulators Stokes Polarimetry APPLICATION NOTE by Dr. Theodore C. Oakberg beforehand. The polarimeter should be aligned so that the James Kemp’s version of the photoelastic modulator was passing axis of the modulator is at 45 degrees to the known invented for use as a polarimeter, particularly for use in linear polarization direction, as shown. The polarizer is oriented astronomy. The basic problem is measuring net polarization at right angles to the plane of the incident linear polarization components in what is predominantly an unpolarized light component. source. Dr. Kemp was able to measure a polarization The circular polarization component will produce a signal at the component of light less than 106 below the level of the total modulator frequency, 1f. If the sense of the circular polarization light intensity. is reversed, this will be shown by an output of opposite sign The polarization state of a light source is represented by four from the lock-in amplifi er. This signal is proportional to Stokes numerical quantities called the “Stokes parameters”.1,2 These Parameter V. correspond to intensities of the light beam after it has passed The linear polarization component will give a signal at twice the through certain devices such as polarized prisms or fi lms and modulator frequency, 2f. A linearly polarized component at right wave plates. These are defi ned in Figure 1. angles to the direction shown will produce a lock-in output with I - total intensity of light beam opposite sign. This signal is proportional to Stokes Parameter U. y DETECTOR y A linear component of polarization which is at 45 degrees to the I x x I x x direction shown will produce no 2f signal in the lock-in amplifi er. -
Polarized Light 1
EE485 Introduction to Photonics Polarized Light 1. Matrix treatment of polarization 2. Reflection and refraction at dielectric interfaces (Fresnel equations) 3. Polarization phenomena and devices Reading: Pedrotti3, Chapter 14, Sec. 15.1-15.2, 15.4-15.6, 17.5, 23.1-23.5 Polarization of Light Polarization: Time trajectory of the end point of the electric field direction. Assume the light ray travels in +z-direction. At a particular instance, Ex ˆˆEExy y ikz() t x EEexx 0 ikz() ty EEeyy 0 iixxikz() t Ex[]ˆˆEe00xy y Ee e ikz() t E0e Lih Y. Lin 2 One Application: Creating 3-D Images Code left- and right-eye paths with orthogonal polarizations. K. Iizuka, “Welcome to the wonderful world of 3D,” OSA Optics and Photonics News, p. 41-47, Oct. 2006. Lih Y. Lin 3 Matrix Representation ― Jones Vectors Eeix E0x 0x E0 E iy 0 y Ee0 y Linearly polarized light y y 0 1 x E0 x E0 1 0 Ẽ and Ẽ must be in phase. y 0x 0y x cos E0 sin (Note: Jones vectors are normalized.) Lih Y. Lin 4 Jones Vector ― Circular Polarization Left circular polarization y x EEe it EA cos t At z = 0, compare xx0 with x it() EAsin tA ( cos( t / 2)) EEeyy 0 y 1 1 yxxy /2, 0, E00 EA Jones vector = 2 i y Right circular polarization 1 1 x Jones vector = 2 i Lih Y. Lin 5 Jones Vector ― Elliptical Polarization Special cases: Counter-clockwise rotation 1 A Jones vector = AB22 iB Clockwise rotation 1 A Jones vector = AB22 iB General case: Eeix A 0x A B22C E0 i y bei B iC Ee0 y Jones vector = 1 A A ABC222 B iC 2cosEE00xy tan 2 22 EE00xy Lih Y. -
A Birefringent Polarization Modulator: Application to Phase Measurement in Conoscopic Interference Patterns F
A birefringent polarization modulator: Application to phase measurement in conoscopic interference patterns F. E. Veiras, M. T. Garea, and L. I. Perez Citation: Review of Scientific Instruments 87, 043113 (2016); doi: 10.1063/1.4947134 View online: http://dx.doi.org/10.1063/1.4947134 View Table of Contents: http://scitation.aip.org/content/aip/journal/rsi/87/4?ver=pdfcov Published by the AIP Publishing Articles you may be interested in Enhanced performance of semiconductor optical amplifier at high direct modulation speed with birefringent fiber loop AIP Advances 4, 077107 (2014); 10.1063/1.4889869 Invited Review Article: Measurement uncertainty of linear phase-stepping algorithms Rev. Sci. Instrum. 82, 061101 (2011); 10.1063/1.3603452 Birefringence measurement in polarization-sensitive optical coherence tomography using differential- envelope detection method Rev. Sci. Instrum. 81, 053705 (2010); 10.1063/1.3418834 Phase Measurement and Interferometry in Fibre Optic Sensor Systems AIP Conf. Proc. 1236, 24 (2010); 10.1063/1.3426122 Note: Optical Rheometry Using a Rotary Polarization Modulator J. Rheol. 33, 761 (1989); 10.1122/1.550064 Reuse of AIP Publishing content is subject to the terms at: https://publishing.aip.org/authors/rights-and-permissions. Download to IP: 201.235.243.70 On: Wed, 27 Apr 2016 20:53:51 REVIEW OF SCIENTIFIC INSTRUMENTS 87, 043113 (2016) A birefringent polarization modulator: Application to phase measurement in conoscopic interference patterns F. E. Veiras,1,2,a) M. T. Garea,1 and L. I. Perez1,3 1GLOmAe, Departamento de Física, Facultad de Ingeniería, Universidad de Buenos Aires, Av. Paseo Colón 850, Ciudad Autónoma de Buenos Aires C1063ACV, Argentina 2CONICET, Av. -
Lab #6 Polarization
EELE482 Fall 2014 Lab #6 Lab #6 Polarization Contents: Pre-laboratory exercise 2 Introduction 2 1. Polarization of the HeNe laser 3 2. Polarizer extinction ratio 4 3. Wave Plates 4 4. Pseudo Isolator 5 References 5 Polarization Page 1 EELE482 Fall 2014 Lab #6 Pre-Laboratory Exercise Bring a pair of polarized sunglasses or other polarized optics to measure in the lab. Introduction The purpose of this lab it to gain familiarity with the concept of polarization, and with various polarization components including glass-film polarizers, polarizing beam splitters, and quarter wave and half wave plates. We will also investigate how reflections can change the polarization state of light. Within the paraxial limit, light propagates as an electromagnetic wave with transverse electric and magnetic (TEM) field directions, where the electric field component is orthogonal to the magnetic field component, and to the direction of propagation. We can account for this vector (directional) nature of the light wave without abandoning our scalar wave treatment if we assume that the x^ -directed electric field component and y^ -directed electric field component are independent of each other. This assumption is valid within the paraxial approximation for isotropic linear media. The “polarization” state of the light wave describes the relationship between these x^ -directed and y^ -directed components of the wave. If the light wave is monochromatic, the x and y components must have a fixed phase relationship to each other. If the tip of the electric field vector E = Ex x^ + Ey y^ were observed over time at a particular z plane, one would see that it traces out an ellipse. -
Wave Optics Experiment 1: Microwave Standing Waves
Wave Optics This project includes four independent experiments. The first three, I think, are fun and surprising. The final experiment is tedious but teaches you about useful optical devices (quarter-wave plates and half-wave plates); half-wave plates are used in the quantum entanglement experiment, for example. Experiment 1: Microwave Standing Waves Objective: To infer that standing waves are created by the superposition of incident and reflected waves between a microwave receiver and transmitter. Introduction: As students varied the distance between a microwave receiver and transmitter, they recorded the data shown in Figure 1.1. Figure 1.1. Microwave intensity at the receiver as a function of distance between the receiver and the transmitter. (Data taken by N. Cuccia.) Why in the world should the intensity behave like this? It's certainly not a "snapshot" of the traveling wave emitted by the transmitter. How did we derive an equation to fit the data? I'll get you started. Suppose that a (sector of a) spherical wave is emitted by the transmitter. Then, the electric field along the line between the transmitter and the receiver is A E cos(kx t) , (1.1) 1 x where A is a constant, and you probably know what everything else is. A little reflection (ha ha!) will convince you that the wave reflected off the receiver is rA E cos[k(2L x) t] , (1.2) 2 2L x where r is the amplitude reflection coefficient, and L is the distance between the transmitter and the receiver. What's the significance of (2L-x)? It's the total distance traveled by the wave. -
Polarization Optics
POLARIZATION OPTICS Retardation Plate Theory Multiple Order Waveplates Achromatic Waveplates A retardation plate is an optically transparent material which As linear polarization enters a crystal, both polarization compo- Using the previous equation, and given a required The wavelength dependence of the birefringence dictates that resolves a beam of polarized light into two orthogonal nents are oscillating in phase with one another. As they propa- retardance value, the necessary thickness of the waveplate the spectral range for the standard waveplate is approximately components; retards the phase of one component relative to gate they begin to fall out of phase due to the velocity differ- can be calculated. For standard waveplate materials, such 10 nm. To accommodate tunable sources or sources with larger the other; then recombines the components into a single ence. Upon exiting, the resultant polarization is some form of as quartz and magnesium fluoride, the calculated thickness spectral widths, a waveplate that is relatively independent of beam with new polarization characteristics. elliptical polarization due to the phase difference. Special polar- for a retardation value of a fraction of a wave would be on wavelength is required This is accomplished with achromatic ization cases can result if the overall phase difference is in multi- the order of 0.1 mm and too thin to manufacture. For this waveplates. ples of � (linear polarization) or �/2 (circular). reason a higher multiple of the required retardation is use to Birefringence place the thickness of the waveplate in a physically manu- An achromatic waveplate is a zero-order waveplate utilizing To better understand phase retardation, birefringence must facturable range. -
Polarization Lecture Outline
1/31/20 Polarization Lecture outline • Why is polarization important? • Classification of polarization • Four ways to polarize EM waves • Polarization in active remote sensing systems 1 1/31/20 Definitions • Polarization is the phenomenon in which waves of light or other radiation are restricted in direction of vibration • Polarization is a property of waves that describes the orientation of their oscillations Coherence and incoherence • Coherent radiation originates from a single oscillator, or a group of oscillators in perfect synchronization (phase- locked, or with a constant phase offset) • e.g., microwave ovens, radars, lasers, radio towers (i.e., artificial sources) • Incoherent radiation originates from independent oscillators that are not phase-locked. Natural radiation is incoherent. 2 1/31/20 Why is polarization important? • Bohren (2006): ‘the only reason the polarization state of light is worth contemplating is that two beams, otherwise identical, may interact differently with matter if their polarization states are different.’ • Interference only occurs when EM waves have a similar frequency, constant phase offset and the same polarization (i.e., they are coherent) • Used by active remote sensing systems (radar, lidar) Classification of polarization • Linear • Circular • Elliptical • ‘Random’ or unpolarized 3 1/31/20 Linear polarization • Plane EM wave – linearly polarized • Trace of electric field vector is linear • Also called plane-polarized light • Convention is to refer to the electric field vector • Weather radars usually