Polarization (also polarisation) is a property applying to transverse waves that specifies the geometrical orientation of the oscillations. In a transverse wave, the direction of the oscillation is perpendicular to the direction of motion of the wave. A simple example of a polarized transverse wave is vibrations traveling along a taut string (see image); for example, in a musical instrument like a guitar string. Depending on how the string is plucked, the vibrations can be in a vertical direction, horizontal direction, or at any angle perpendicular to the string. In contrast, in longitudinal waves, such as sound waves in a liquid or gas, the displacement of the particles in the oscillation is always in the direction of propagation, so these waves do not exhibit polarization. Transverse waves that exhibit polarization include electromagnetic waves such as light and radio waves, gravitational waves, and transverse sound waves (shear waves) in solids.
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.
Light or other electromagnetic radiation from many sources, such as the sun, flames, and incandescent lamps, consists of short wave trains with an equal mixture of polarizations; this is called unpolarized light. Polarized light can be produced by passing unpolarized light through a polarizer, which allows waves of only one polarization to pass through. The most common optical materials do not affect the polarization of light, however, some materials—those that exhibit birefringence, dichroism, or optical activity—affect light differently depending on its polarization. Some of these are used to make polarizing filters. Light is also partially polarized when it reflects from a surface.
According to quantum mechanics, electromagnetic waves can also be viewed as streams of particles called photons. When viewed in this way, the polarization of an electromagnetic wave is determined by a quantum mechanical property of photons called their spin. A photon has one of two possible spins: it can either spin in a right hand sense or a left hand sense about its direction of travel. Circularly polarized electromagnetic waves are composed of photons with only one type of spin, either right- or left-hand. Linearly polarized waves consist of photons that are in a superposition of right and left circularly polarized states, with equal amplitude and phases synchronized to give oscillation in a plane.Polarization is an important parameter in areas of science dealing with transverse waves, such as optics, seismology, radio, and microwaves. Especially impacted are technologies such as lasers, wireless and optical fiber telecommunications, and radar.
Hi Everybody,
I'm currently working my way through Sakurai's second book, "Advanced Quantum Mechanics."
I'm getting held up on a short several paragraphs on the connection between photon spin and polarization.
On pages 42-43, Sakurai states:
"Since the polarization transforms like a...
When summing over photon polarizations for a given amplitude if it can be written as:
M = M^{\mu} \epsilon^{*}_{\mu}}
then
\sum_\epsilon |\epsilon^{*}_\mu M^\mu |^2 = \sum_\epsilon \epsilon^{*}_\mu epsilon\nu M^\mu M^{* \nu}
and you can replace the sum over polarizations with a -g_{\mu...
Hi there.
Sorry for my poor English first.
I have been reading chapter about polarization in Feynman Lectures on Physics.
There is a experiment about polarization using 2 polaroids and birefringence cellophane located between two polaroids.
optic axis of two polaroids are 0 and 90 in...
Homework Statement
A coaxial cable of circular cross section has a compound dielectric. The inner conductor has an outside radius a , which is surrounded by a dielectric sheath of dielectric constant K_1 and of outer radius b . Next comes another dielectric sheath of dielectric constant...
I find that some book e.g. Many-body theory of solids by John C. Inkson P145
says that :" By analogy with the classical polarization, we define a polarization
propagator through the relationship ... ε=1-vP" , where ε is the dielectronic response function, and v is the bare Coulomb...
Hi,
I have a particle physics exam tomorrow morning (in a few hours from now, in my time zone). I'm trying to figure out the whole reasoning behind pion-nucleon scattering. Please bear with me..
We write the scattering matrix as
S = 1 - iT
where T is given by
T = f + i g...
After we measure the position of a particle fairly sharply, it “spreads out” or the uncertainty grows according to the Heisenberg uncertainty principle. After we measure the polarization of a photon, does it spread out, too? If not, why not? If so, how fast?
TIA
Jim Graber
how to find which polarization ??
a classical charged particle moving with frequency 'w' in a circular orbit of radius 'a' centerd at the origin in the x-y plane, em radiation. At points (b,0,0) and (0,0,b) where b >> a the em waves are
1. circularly polarised and elliptically polarised...
Does anyone here use Feyncalc? (Or have a better alternative).
I have terms that I need to simplify like :
(2 Pair[Momentum[p1], Momentum[PB]] Pair[Momentum[p2],
Momentum[Polarization[q, -I]]] Pair[Momentum[PB],
Momentum[Polarization[q, I]]])/(
Pair[Momentum[p1], Momentum[q]]...
Vacuum polarization is when an EM field causes the virtual particle pairs around it to become polarized like a dipole. The most common example is with an electron in vacuum, but a transmitting radio antenna could do it as well. But, if this was with an oscillating signal, it would create waves...
Homework Statement
in a homework problem we have a spherical dielectric shell with permittivity of 1 [like a vacuum. inside are charges that are released and we have to say what the charge distribution will look like later. if the dielectric can be polarized, i know what the charges will do...
Part of my independant investigation requires me to carry out an experiment, which when I graph results, would confirm Malus' Law.
I plan on using a bulb as my ambient source and two polarizing lenses. I will then measure the intensity of the light after polarization. Hopefully, if i graph...
I have an optical fiber system that consists of a linear polarizer, a manual polarization controller, and a reflector (Bragg grating).
I want to make sure that the polarization at the Bragg grating is circular (either right or left circular will do).
Can someone tell me if the following...
i read this "in electrodynamics, polarization characterizes em waves, such as light, by specifying the direction of the wave's electric field" in a book.
i really didn't get it clear & does the magnetic filed nothing to do with polarization?
A beam of unpolarized light (III=IP= I0 and EII= EP= E0) is incident from air on a plane interface of water (n = 1.33).
(a) Under the incident angle of θi = 0°, 30°, and 70°, what is the amplitude (E) and intensity (I) of the reflected beam (relative to the values E0 and I0 of the incident...
In the energy producing region of the sun there is a large radial flux of high energy photons. Does this outward flux polarize the plasma and give rise to a electric field in this inner region? What is an order of magnitude estimate of this field?
As the sun rotates this field gives rise to a...
Homework Statement
Characterize the polarization (i.e., linear, circular, or elliptical) of the transmitted and reflected waves for the case in which a circularly-polarized field is incident on an interface at Brewster's angleHomework Equations
N/A
The Attempt at a Solution
I thought that...
In the text, it is said that the polarization is just the response of the input electric field so they have
P = \epsilon_0 \chi E
where P is the polarization and E is the input.
This makes sense to me. However, why we need \epsilon_0 sitting there? Since \epsilon_0 has no dimension, so...
Is anybody knows what kind of equipment or lens can be used to change the direction of the polarization of the laser light (electrical field and magnetic field, but not the direction of the light)? Thanks.
Homework Statement
Describe how a metal sphere on an insulating stand is charged if a positively-charged rod were to touch the sphere. (This is a 5 mark problem, so at least 5 major points should be included in the answer. I am not sure whether I have fully answered the problem.)
Homework...
Hello every body;
I am having a problem understanding how light is polarized by reflection, what happens during the process, and why is it polarized at a particular angle "Angle of Polarization". Can you please help me with this problem? I'll be thankful.
Homework Statement
What property of the photon is responsible for the absence of longitudinal polarization?
Homework Equations
The Attempt at a Solution
I thought it is because of the presence of its angular momentum. Is it true?
I'm sorry if what I say is not right, or I haven't understood it right,
- In 3+1 D we have the photon with spin 1 => it has two polarizations.
Our Gauge field A_\mu has 4 components => We have two extra degrees of freedom. => We need to get rid of the extra 2 fixing the gauge. 1. The...
Hi,
Can someone explain the concept of "Poincare sphere"? What's the relationship between the Poincare Sphere and the Degree of polarization of EM fields?
Thanks
Madara
Hey all,
Polarization of light is still confusing for me :-( i read a lot but i couldn´t clear my concept . can anybody of yous explain...
I would be very thankful.
Best regards
Abid
Statement:
Consider two dipole antennas, oriented 90degrees apart [imagine the x-y plane, let "a" be the dipole oriented along the x-axis, and the "b" be the dipole oriented along the y-axis]. If "a" dipole radiates cos(\omega t) and "b" dipole radiates sin(\omega t), the field radiated by the...
Statement:
Consider two dipole antennas, oriented 90degrees apart [imagine the x-y plane, let "a" be the dipole oriented along the x-axis, and the "b" be the dipole oriented along the y-axis]. If "a" dipole radiates cos(\omega t) and "b" dipole radiates sin(\omega t), the field radiated by the...
Statement:
Consider two dipole antennas, oriented 90degrees apart [imagine the x-y plane, let "a" be the dipole oriented along the x-axis, and the "b" be the dipole oriented along the y-axis]. If "a" dipole radiates cos(\omega t) and "b" dipole radiates sin(\omega t), the field radiated by the...
#degrees of polarization of a spin 1 or 2 particle
On page 32 of Quantum Field Theory by A. Zee, he expects you to remember the concept of polarization, specifically how to extract the number of degrees of polarization of a spin 1 or 2 particle.
As I seem to remember from EM class...
Hi,
I read several literatures on quantum cryptography plug and play system. I found out that Faraday mirror was used to compensate polarization fluctuations. Photons are reflected orthogonally by Faraday mirror and their polarization changes will then be autocompensated, provided they follow...
Following Fig. 1 in the following paper:
Eberly (2002): Bell inequalities and quantum mechanics
In an ideal case (this is far from easy to do): Send an incident beam from one side of entangled photon pairs into a beamsplitter, and then recombine the outputs back into a single stream. Let's...
I was wondering how exactly a single photon is polarized. In the case of an electromagnetic wave in theoretical free space Maxwell's equations state that electric and magnetic fields must be equal in amplitude and in phase with each other. On wikipedia's "photon polarization" article it states...
Hi I’m a student, and I started reading Zwiebach’s First Course in String Theory, but I still haven’t learned general relativity, only special relativity, and so I’m having some difficulties in understanding the polarization tensor for the perturbation of the Minkowski metric leading to the...
The wikipedia page on photoelectric effect
http://en.wikipedia.org/wiki/Photoelectric_effect
talks of a 5th experimental result, which I hadn't heard before:
"The direction distribution of emitted electrons peaks in the direction of polarization (the direction of the electric field) of the...
Can somebody explain me what are precisely the polarization vectors of a photon and how they relate to the photon's momentum and helicity ?
Or give me reference of textbooks in which I could learn more on this topic ?
Thanks a lot for your help!
Hi.
It is supposed that External field imposes to dielectric matter and Polarization occurs.
Thus, Bounded volumb and surface charge are made.
My question is, is field induced by Bounded charge in addition to original(external) field
different from original field existing...
Hi all,
I'm implementing ray tracing ..
If we say that an antenna is linearly vertically polarized, does that mean that the direction of E field emitted from the antenna is vertical with respect to the coordinates of the antenna or vertical with respect to each ray's coordinates?
For...
I am currently doing experiments with polarizing optics and reflection from metal surfaces. However it's not as simple as it sounds in textbooks, so I was wondering if anyone had experience in these type of experiments.
There seems to be a fundamental problem with identifying the transmission...
Homework Statement
At what angle above the horizon is the Sun when light reflecting off a smooth lake is
polarized most strongly?
Homework Equations
dsin(θ) = mλ
I = E^2
The Attempt at a Solution
I think that the polarization is strongest when the angle between the light...
Hi everyone, I am a little bit confused on a concept relating to optics. If we have an interferometer (lets say a Sagnac interferometer) after the two beams traverse equal paths and recombine, the S and P polarizations are in phase but orthogonal. Does this mean that the light is essentially a...
1. Here's the question:
The percent polarization P of a partially polarized beam of light is defined as
P = [Imax - Imin]/[Imax + Imin] x 100
where Imax and Imin are the max and min intensities that are obtained when the light...
From a classical perspective, linearly polarized light can be converted to circular by introducing a phase shift between the orthogonal modes.
Could someone give me an explanation of how this works from a quantum mechanics perspective, starting from the fact that each photon has angular...
I have question about the two degrees of polarization of light. I know for a fact that light has only two degrees of polarization for a fact, which just means that light is transverse, but i want to understand what does the longitudinal electric field that you get from a columb field mean...
I noticed that steel or iron objects tend to magnetically polarize in the Earth's magnetic field. I am in Kazakhstan (northern hemisphere! :-) The north pole of the magnetized objects seem to be at the top of the objects. Is this a coincidence? If not what is the explanation? Would it be...
Hi members, am new to antenna field.I would like to know more about polarization in waveguide.As per book,it is stated that TEM wave cannot travel in waveguide.If that is the case how come horizontal or vertical polarization can be achieved.If am wrong,please correct me.Thanks in advance.
Homework Statement
I'm trying to derive the stefan-boltzman law by considering a box of photons (as in Landau and Lifgarbagez and other texts). At one point in the derivation we multiply the density of states by 2 in order to account for the two independent polarizations of a photon. But at...