What is Polarization: Definition and 662 Discussions
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.
I was trying to search for a similar topic, but as I haven't found one here it goes.
Thought experiment: Periodically emitted chain of single photons of non-polarized light is split into two entangled pairs and they are traveling apart from each other. One going toward point A, the other toward...
Homework Statement
A half-wave plate is put between an horizontal polarizer and a vertical analyzer, so we have extinction.
If the anylizer is rotated clockwise an angle Theta, Which angle do we have to ratate the polarizer to keep the extinction of the light?
Homework Equations
The...
I thought if it`s possible to create a device which would be a something average between
capacitor and solar cell.In solar cell we are getting non-uniform charge separation which is then used to produce current with help of low voltage electric field.Current which could be acheived in solar...
I'm trying to understand the meaning of polarization. I know the actual definition, which concerns the directions in which a transverse wave oscillates, as opposed to the direction of propagation. For instance a standing wave on a string is linearly polarized in the vertical direction, meaning...
Homework Statement
I was stuck on a question today in my Optics exam (I didn't have time to think well about it but I'm still stuck).
The problem was more or less like this: There's an incident linearly polarized light in the direction of \hat x; we want to polarize it so that we get \hat E =...
Homework Statement
A linearly polarized wave incidates over a surface of a material with a higher refractive index than the incident media one. See picture for clarification. The polarization is such that the E field isn't perpendicular nor parallel to the plane of incidence. Rather, it's...
Homework Statement
Long dielectric cylinder of radius R carries a built-in electrostatic polarization P
that is linearly proportional to the distance to the axis, P=\alphar, P is directed along
the radius-vector r. Cylinder is being rotated around the axis with angular velocity
\omega...
Homework Statement
The question reads "What is the polarization of the following waves?"
1)\vec E = E_0 [\hat i \cos (\omega t - kz) + \hat j \cos (\omega t - kz + \frac{5 \pi}{4}) ].
2)\vec E = E_0 [\hat i \cos (\omega t + kz) + \hat j \cos (\omega t + kz - \frac{ \pi}{4}) ].
3)\vec E =...
light reflected off road surfaces or water surfaces is HORIZONTALLY polarised. Why is this?
I would presume therefore that if reflected light is horizontally polarised, light reflected by objects beneath the water is vertically polarised (assuming you see it from under water)
I have this problem for homework and I don't even know where to start... I would really appreciate any help !
Homework Statement
An isolated metal sphere of radius a has a free charge Q on its surface. The sphere is
covered with a dielectric layer with inner radius a, outer radius b, and...
Dear all
In case of a material that instantaneous responds to an external applied field is
P(r,t)=χE(t)
Is the suseptibility then time independent? And if so, how it is possible to derive from the above equation an equation in the frequency domain?
Yours
Homework Statement
A glass vessel is placed between a pair of crossed HN-50 linear polarizers, and 50% of the natural light incident on the first polarizer is transmitted through the second polarizer. By how much did the sugar solution in the cell rotate the light passed by the first...
Concept check:
A Right hand circular polarized wave is having the E vector circulates in the direction of the fingers with the thumb in the direction of wave propagation with its components Ey leading Ex by 90 degrees?
Imagine an unpolarized EM wave going into the z direction. Put a polarizer so that you linearly polarizes the EM wave. I know that the electric field direction of the wave will always be the same. But what about its magnetic field?
Is it possible to affect the magnetic field of an EM wave...
Just want to make sure if I have this correct and to ask a question,
If you pass an electric field through an atom, it polarizes it the atom with a dipole moment p = \alpha E where is a constant of polarizability and E the electric field. Because of the electric field, the nucleus moves in the...
Homework Statement
Show that the polarization of a material is P=Nqx where x is the displacement between the center of the electron cloud and the atomic nucleus.
Homework Equations
P=Nqx is given and I went ahead and subbed (q/m) * E[1/(w0^2 - w^2)] for x.
The Attempt at a Solution...
Homework Statement
a) A beam of light in the air strikes the surface of a smooth piece of plastic having an index of refraction of 1.55 at an angle with the normal of 60 degrees. The incident light has equal component E-field amplitudes parallel and perpendicular to the plane of incidence...
The vacuum polarization result in QED seems to always be written in a "QED form". I would be interested in seeing it in an old-fashioned classical physics form.
Without vacuum polarization the electric potential in a region containing a point charge is of course Q/r. So if the vacuum...
Can anyone direct me to manufacturers/suppliers of the complete setup for the Polarization by Quarter-wave Plates Experiment? I have already found one: PHYWE Systeme (Germany) - http://www.phywe.com/461/pid/26331/Polarisation-durch-Lambda-Viertel-Plaettchen-.htm" , but I need at least two more.
so I'm using my laptop outside while also wearing polarized sunglasses. I've only taken up thru physics 2 and it's the summer so ( ) and I'm not mentally on my A game so to speak. But I want to know if my impression here is close to correct or the...
"Polarisation" is defined as the cofinement of the vibrations of the wave in only one plane and the removal of the vibrations in the other perpendicualar plane of the electromagnetic wave. But the e.m. wave is defined as a wave in which the electic vetors are restricted in one plane only where...
*I am using the conventions of circular polarisation according to electrical engineering , not the one used in optics*
Let us take a uniform plane TEM wave traveling in +z direction which is composed of two linearly polarised TEM waves , one whose electric field lies in X direction , the other...
Let us consider the Electric field components of a polarized EM wave .
[PLAIN]http://www.cdeep.iitb.ac.in/nptel/Electrical%20&%20Comm%20Engg/Transmission%20Lines%20and%20EM%20Waves/graphics/CHAP%204__255.png.
Now if we fix the value of z (for convenience take z=0) and consider the locus of...
Hi:smile:
I have a question about a circularly polarized wave.
Once this wave passes through a linear polarizer - how is the wave intensity changed?
Someone has told me that the intensity decreases to its half value, but I’ve read somewhere the intensity is not changed…
So… what is the...
Consider a uniform, isotropic , homogeneous solid dielectric slab.
We know, induced surface charge=\overline{P}.\widehat{n}
and \overline{P} \alpha \overline{E}
So, as applied electric field increases, polarization per unit volume increases.
which implies that surface...
Suppose we have a fixed coordinatre system (x,y,z). Suppose an antenna is horizonally polarized. Is the orientation of the E field fixed as a function of (x,y,z). Or does it change?
Hi, I'm having difficulty understanding exactly how the reciever loop detects the EM waves in this experiment and I can't find any definitive information online.
My understanding is that since EM waves are transverse, to be absorbed by the receiving electrodes, the length of the molecule chains...
I'd like to test my understanding of polarization, concept new to me. I except that the answer to my following question is "no", but I'm not sure and I don't know why it would be so.
If I see a circularly (left of right, it doesn't matter) polarized EM wave going to my eyes and I put a...
Hi all,
When viewing 3D films, you are given a pair of glasses without which, the pictures are bad and blur . So what is the principle of the technique? Is that polarization of the light?
Thanks
Let us imagine a surface, with X and Y axes on it and Z axis normal to it.
well, the theory, (in my particular case, some article) says that S polarized light, propagating along the x-directioin possesses only electric field components, Ei, parallel to the surface (||y-direction), i.e...
When light enters a substance that polarizing it by scattering does that mean that the medium sends all the consituent light waves off in different directions depending on what direction they are oscillating in? In other words does the scattering of a beam of light split it into it into a load...
Homework Statement
compute the polarization state for the following scenarios:
The input light is randomly propagated in the z direction (figure attached) and then passes through a linear polarizer oriented 45° from either the x or y axis.
1-After the linear polarizer, the light passes...
Homework Statement
At a beach the light is generally partially polarized due to reflections off sand and water. At a particular beach on a particular day near sundown, the horizontal component of the electric field vector is 1.8 times the vertical component. A standing sunbather puts on...
Homework Statement
I'm using Eugene Hecht's 4th edition of Optics, doing problems from chapter 8 on polarization.
Write an expression for a polarization-state lightwave of angular frequency (omega) and amplitude E propagating along the x-axis with its plane of vibration at an angle of 25...
Homework Statement
The magnetic component of a polarized wave of light is given by:
Bx = (4.00μT ) sin[ky+(2.00×1015s−1)t]
What direction does the light travel, and which axis is the polarization parallel to?
Homework Equations
vector E x vector B gives direction of the light wave...
Hi,
I stumbled upon this dilemma in a homework problem which involved 2D photon gas (unphysical, I know). How many polarization states are there for EM-radiation confined to 2D? In 3D it's 2, but how does it work in 2D? An EM-wave propagating in the z-direction can have its E-component...
if a di-electric was introduced to an electric field from the outside it would be polarized and the charge denisties would be as follows :
**volume bounded charge density ( ρv ) = - div ( P )
**surface bounded charge density ( ρs ) = P . n
where P is the polarization vector and n is the...
Homework Statement
http://xs.to/image-A876_4BAF6DF1.jpg
alpha = 54.6 degrees
I need to calculate phase difference between E(perpendicular) and E(parallel) polarization components.
Homework Equations
The Attempt at a Solution
Problem is I don't know any relevant equations...
Homework Statement
Two polarizers are oriented at 62° to one another. Light polarized at a 31° angle to each polarizer passes through both. What reduction in intensity takes place?
___.%
Homework Equations
I=IoCos^2((-))
The Attempt at a Solution
Tried suing the above equation...
It took me a little while to wrap my head around circularly polarized light, or more specifically how this can be done "passively". Wikipedia didn't do much help until I found the article at Polarizer, if any of you were wondering how the new 3D movie technology works.
My first question is...
Homework Statement
Which model of light is used to explain polarization?
Ray optics or particle model?
Homework Equations
The Attempt at a Solution
I don't know. My guess is particle model.
All I know is that polarization density satisfies two equations
\[
\begin{array}{l}
\rho _{bound} = - \nabla \cdot \vec P \\
\sigma _{bound} = \vec n_{out} \cdot \vec P \\
\end{array}
\]
This is the divergence and boundary conditions of P.But to determine a vector field...
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...