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Questions tagged [polarization]

Polarization characterizes the oscillations in time the electromagnetic field is doing in the plane perpendicular to the propagation direction of a wave

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I am studying polarization of EM waves. Where does this general form come from?

This is a snapshot from The Physics of Waves by Georgi. I am wondering if anyone could explain where this general form of polarization vector comes from? Thank you very much.
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Why do we ignore magnetic field vector during polarization?

Most light sources in nature emit unpolarized light. Natural light sources consist of very large number of randomly oriented atomic emitter, which emit polarized light randomly. A linear polarizer is ...
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Energy momentum tensor in polarizable media

I am trying to follow Soper's derivation of the energy-momentum tensor for polarizable media in his book 'Classical field theory'. Given a Lagrangian density $\mathcal{L} = \mathcal{L}(\phi_A, \...
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Is the Lorentz transform of a bound current - a bound current?

The bound (magnetization) current is $\mathbf{J}_\mathrm{M} = \nabla \times \mathbf{M}$. The charge density of a moving magnet that is electrically neutral in its own rest frame satisfies the ...
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Spherical capacitor with dielectrics [closed]

Consider the following system: which consists of a conducting sphere with free charge 𝑄, a dielectric shell with permittivity $\epsilon_1$, another dielectric shell with permittivity $\epsilon_2$ ...
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Depolarization factors of a drude metal plasmonic spheroid

A practice question asks for the depolarization factors $ L_{i=x,y,z} $ of a plasmonic spheroid made of a drude metal having the same resonance as the SPP resonance frequency. The answer turns out to ...
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Stokes vectors and fractional polarisation

I am struggling to be able to write this problem as a Stoke's vector. I understand how to set it up, but am not sure if you need two separate vectors that you combine or just one. Any help would be ...
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Polarization on a spherical electromagnetic wave in free space using classical electromagnetism

The polarization of a plane wave traveling in free space is well defined and traverse to the direction of propagation from classical electromagnetic theory. Spherical waves are another type of ...
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Polarization ellipse for an EM wave [duplicate]

In Chapter 7 of Jackson's book on Classical Electrodynamics, there's the following statement: Introducing the complex orthogonal unit vectors: $$\epsilon_{\pm}=\frac{1}{\sqrt{2}}(\epsilon_1\pm\...
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Question on oscillation of Electric field vector

I was reading Feynman Lectures on Physics in which he explains the direction of oscillation of electric field vector. If you see figure 33-2 g , you will find that $E_x = \cos \omega t$ $E_y = \sin \...
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How to determine the axis of a polaroid?

I have found a polaroid from an old LCD device. It is rectangular in shape and does not have any markings on it. I wanted to somehow determine its axis, maybe not exact. I have tried to use it in ...
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Can we choose polarization vectors freely in any given gauge theory?

When quantizing a gauge theory, we obtain spin-1 particles propagating in space-time. When we want to count the degrees of freedom of the theory or, equivalently, when we are trying to decompose the ...
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Does a polarizer affect both entangled photons or only one?

Suppose you have two polarization-entangled photons A and B in the following state: \begin{equation} \Phi=\frac{1}{\sqrt{2}}\bigl(\left|H_{A},H_{B}\right\rangle + \left| V_{A},V_{B}\right\rangle\bigr)...
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Combining light of the same linear polarisation

Is there a way to combine two (coherent) beams that have the same polarisation and wavelength in a lossless manner such that the resultant beam has the same polarisation as the starting beams? I'm ...
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What's the difference between linearly polarised and plane-polarised waves?

To explain polarisation, my book gives an example of a transverse wave in a string, and explains as: Since each point on the string moves on a straight line, the wave is also referred to as a ...
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Refraction of a circular polarised wave

I'm trying to derive the expression for the fields $E_{1}$ and $E_{2}$ in terms of $n_{1}$, $n_{2}$ and $E_{0}$. Where: $E_{0}$ Is the incident field amplitude of circular polarised light $E_{1}$ Is ...
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Can I couple 1064 nm and its harmonic 532 nm in a single polarization maintaining fiber?

I have an experiment where I need to get a largish (40 mW) amount of 532 nm light and small amount (<50 µW) of 1064 nm light into a device under test. I need something with stable polarization so ...
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Sending elliptically polarised beams into a reversed beam splitter

If I send two elliptically polarised beams into the outputs of a (say 50:50) beam splitter which is at some angle $\theta$ to the $x$-axis, what sort of beam emerges? As far as I'm aware they do not ...
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How can non-polarised light exist? [duplicate]

Typically unpolarised light is shown like this: Basically, from what I've seen, unpolarised light is just a lot of overlapping individual light waves. However, if they truly overlapped, would their ...
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Express polarization moments in terms of temperature quadrupoles

I am trying to compute the polarisation moments in the tight coupling limit which is an exercise from Dodelson's Modern cosmology where the evolution equation is given by $$\dot{\Theta}_p+ik\mu\...
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Is it possible to induce left-handed electromagnetic wave from positrons? [duplicate]

All observations of electromagnetic induction we have, are from the flow of electrons. The accelerated electrons in the antenna rod induce an EM wave with a right handed system of the electric field ...
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polarization of ordinary light, laser and photons of atomic transition

The light from thermal sources such as a light bulb is unpolarized but the one from a laser is polarized. Why? Is a photon emitted in an atomic transition linearly or circularly polarized and a ...
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Do polarizers also shift the phase of light?

When does passing through a polarizer change phase besides just changing polarization? Consider three cases: A polarizing beam splitter (PBS) is a clear case. Horizontally polarized light leaves ...
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Description of quantum state of entangled photons after polarizer

I'm wondering if anyone can help me understand how a polarizer changes the quantum state of two polarization-entangled photons. I haven't found a clear description in the literature. Suppose you have ...
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Can you polarise a lens by rubbing it with your finger?

Here's a phenomenon that you all might have come across . I took two photos on my phone, keeping it in landscape mode. I noticed that the light rays get polarised, or rather "smudged" when I rubbed ...
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Spin (helicity) and polarizations of photons: are they secretly related?

Edit Circularly polarized photons have $$\textbf{S}\cdot\hat{\textbf{p}}=\pm \hbar\tag{1}$$ and it also satisfies $$\boldsymbol{\epsilon}\cdot\hat{\textbf{p}}=0\tag{2}$$ where $\textbf{S}$ is the spin,...
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Jones representation of Unpolarized light

What is the Jones matrix representation of completely unpolarized light? Context : Majority of astrophysical sources' emission is totally unpolarized or partially polarized. I need to know the ...
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What's the difference between twisted light and light of circular polarization?

Circular polarization: https://en.wikipedia.org/wiki/Circular_polarization Orbital angular momentum of light: https://en.wikipedia.org/wiki/Orbital_angular_momentum_of_light From point of view, ...
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What is the polarization loss between RHCP transmitter, aircraft reflection, and reception by vertically polarized antenna?

A stationary transmitter transmits RHCP radio waves. These are reflected by aircraft as LHCP. A stationary receiver receives them using a vertically polarised Yagi-Uda antenna. Is the polarization ...
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Orientation of the linearly polarized light comming from circularly polarized light that went through a quarter waveplate

If circularly polarized (CP) light enters a quarter waveplate (QWP), it is converted to linearly polarized (LP) light. But what is the orientation of the resulting LP light? Does it depend on the ...
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Double silt experiment with one circular polarizer in front of only one slit in the which-way perspective?

If one puts in front of a double slit two quarter-wave circular polarizers (QWP) in front of each slit, say one with 45° and the other with -45° orientation (fast and slow axis - i.e. clock- and anti-...
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unusual questions regarding controlling polarized light with LCD shutters

1) Is it correct to assume that if a light is already polarized one of the polarizers on the LCD shutter itself is not required to be present to selectively block it? 2) Is it correct to assume that ...
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QCD gluon physical polarisation sum in the three gluon vertex

In the Compton scattering quark($p_1$) + gluon ($q_1$)-> quark($p_2$) + gluon($q_2$), there is three gluon vertex contribution. If we choose the physical polarisation sum $\sum_{\lambda} \epsilon^a(\...
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Does polarized light reflect in the same polarization?

If vertically polarized light hits a linear polarizer aligned at a 45 degree angle from the polarization of the light, my understanding is 50% of the light will pass through and have its polarization ...
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Why do mirrors not follow brewster's angle?

Normally a material will have an angle where the reflected light is completely polarized. Now say we have a mirror (implemented by a conductive silver coating) that reflects most of it's incident ...
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Spectrum of Dielectric Function along Energy

What do the peaks and troughs in the spectrum of the dielectric function (real and imaginary parts) along energy indicate? I understand that the real part represents the polarization and the imaginary ...
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Dielectric polarization - should not the dimensions of the polarised dielectric increase in the direction of the field?

In the classical model for polarization, if a dielectric is placed in a an electrical field (assumed to be static for the sake of simplicity), the trajectory of the electrons inside the atoms of the ...
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Electric Field & Polarization

Does everytime the electric-field $E$ & the electric displacement vector $D$ are parallel for every material?
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Is the direction of the electric field relative to the magnetic field in an electromagnetic wave a convention?

In an electromagnetic wave. Could the magnetic field be mirrored around the xy-plane? Is there a specific reason that the 2 fields are oriented this way? Is it just a convention?
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Propagators for polarised photons

Photons can be thought to come in two types. Depending on which way they are spinning. The propagator for a photon (sum of both helices) in a certain gauge is $\frac{\eta^{\mu\nu}}{|k|^2}$. I read ...
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Does the inverse-square law apply to linearly polarized light?

It's a stupid question but: We did and experiment using linearly polarized microwave radiation generators and receivers. Our teacher asked to check experimentally if the receiver measurements are ...
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Does the external leg contraction of gluon in QCD carry group generator index?

While I am trying to compute the amplitude for the following Feynman diagram I realized that the external leg contraction of $g$ should carry group generator index $A$ or $B$, is that right? If so, ...
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Unpolarized light, spherical wavelets and Photons

Before I get to the core of my question, I would like clarify my understanding of unpolarized light. Below are 2 images of unpolarized light from Google: The first one seems to be in accordance with ...
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Is there an Heisenberg uncertainty relation for light polarisation?

While reading some questions about the polarisation of a photon, I was wondering about its quantum mechanical representation as a classical vector in the electromagnetic field operator : \begin{...
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Deriving the electric displacement field ($D$ field)

I am trying to derive the $D$ field (or electric displacement field): $$D=\varepsilon _{0}E+P$$ I am using the following relationships: $$\rho=\rho_{f} + \rho_{b}$$ $$ \rho_{b} =-\nabla \cdot P$$ ...
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Does polarization happen with single Photon?

I have read that circularly polarized light forms from the superposition of two linearly polarised light. Then is it true that polarisation can't happen with single Photon because it always need at ...
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The potential difference when neutral dielectric ($\varepsilon_r$) flows with speed $v$ through capacitor in magnetic field $B$

The distance between the two parallel plates of the initally discharged capacitor is $d$. Parallel to the plates there is a magnetic field $B$, as the image shows: So we want to know the potential ...
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Why do nearby charges increase the probability of virtual particles?

I'm a layperson currently reading through Matt Strassler and on his website, he states, in relation to using positronium as an example of vacuum fluctuation effects: The stronger force between the ...
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Can polarised light become unpolarised light as it travels through space?

Is the polarization of a light beam permanent? I mean, does the polarization change as it travels through vacuum? If so, what causes it to change?
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Circularly Polarized Light Through a Linear Polarizer

When a circularly polarized light is incident on a linear polarizer, shouldn't the transmission of said light be dependent on the momentary orientation of the polarization at the instance of incident? ...