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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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Molecular polarizability equation check

ChatGPT gave me an equation to calculate the molecular polarizability using the fluctuation of the dipole moment components, but I can't verify its validity because it gives me a made up reference. I'...
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Link between photon helicity and polarization of $A^\mu$ electromagnetic potential

From Wigner theorem we know that the irreducible unitary representation of the Poincarè group for massless and spin 1 particle is labelled by the momentum $p_\mu$ and the two possible helicity $+1,-1$ ...
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Polarization analyzer [closed]

My understanding is that the entanglement between two photons is not broken by a polarization analyzer. One will emerge from the Y projector and one will emerge from the X projector. Is this correct?
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Displacement current and magnetic field in capacitor with dielectric

I have a capacitor with round plates of radius $r_{2}$ kept at a distance $d$, with a voltage $V\left(t\right) = V_{0} \cos \left(\omega t\right).$ Inside, there is cylindrical material with a certain ...
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Is there any specific terminology for this type of current in spintronics?

In spintronics, there are several types of currents: Spin-polarized current: The two spins flow in the same direction with unequal contributions. Perfectly spin-polarized current: Only one species of ...
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Why does an atom become positively charged when it shares its lone pair?

Why does an atom become positively charged when it shares its lone pair? In NH3, Nitrogen doesn't get positive charge when forming covalent bond with Hydrogens. But why does it get positive charge ...
Akhilesh G's user avatar
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What is the advantage of using spherical tensor over cartesian tensor?

I am trying to train a machine-learning model to forecast the polarizability of atoms within a molecule. Typically, the tensor is characterised as a Cartesian rank-2 tensor, like this: $$\alpha= \...
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Decomposing physical degrees of freedom for spin-3 (Schwartz)

In section 8.7.2 of Schwartz, he decomposes the polarization vector for a massive spin-2 particle into 2 transverse and 3 longitudinal components, $$h_{\mu\nu} = h^T_{\mu\nu} + \partial_\mu (\pi^T_\nu ...
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Difference between polarization angle and poling angle in piezoelectric material

I was reading the research article: Demonstration of optimizing piezoelectric polarization in the design of a flextensional actuator, where I had confusion differentiating between poling angle, which ...
user134613's user avatar
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Confusion on the definition of dielectric permittivity

I don't understand how we're defining the dielectric permittivity, sometimes it's defined as the ability of the material to resist the electric field and sometimes as the ability to permit the ...
Manish Parmar's user avatar
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Does the creation operators for photons with different polarization commute?

Let $\hat{a}^{\dagger}_{\sigma}$ be the creation operator of a photon with the polarization $\sigma $ towards some reference. What are the commutator relations for the creation operators of a photon ...
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Average polarization of photons and lasers

Sunlight is made up of photons polarized in many directions, so it is derived that sunlight has a 50% chance of passing through a polarizing filter at any angle. My question is, if you know 50% of ...
Vinicius Araujo Ritzmann's user avatar
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Bound Charges in Polarized Material

I'm currently working my way through chapter 4 of Griffith's Introduction to Electrodynamics (4th ed) and I ran into an issue with his notation. In chapter 4 sectin two, when calculating the electric ...
ReggiePlasmaQs's user avatar
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Polarization by Polaroid [duplicate]

A Polaroid is made up of slits aligned in a specific direction. Before passing through the Polaroid, electric field and magnetic field vectors of light (suppose from a bulb) aligned in random ...
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How is the local field in a dielectric material calculated?

I have read in different sources (text, video, amongst others) that the local field in a dielectric material placed within a capacitor can be easily calculated as the sum of 4 electric fields: $E_{...
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Mode expansions of canonical quantized fields in QFT

I have been self-studying QFT Quantum Field Theory for the Gifted Amateur by Stephen Blundell and Tom Lancaster. They devote Chapters 11, 12, 13 to the subject of canonically quantizing any given ...
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Color changes with polarization

Plane polarized light is passed through a second polarizer whose polarizing direction is, say, at $80^o$ to the polarizing direction of the first polarizer. How does one experimentally measure the ...
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Polarization in nonlinear optics

I've very recently started learning nonlinear optics by reading the well-known textbook by Robert W. Boyd (3rd ed.). I don't find the book an excellent choice for self-study. The fundamental concepts ...
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What happens when a linear polarized EM wave encounters a perpendicular mesh of wires (which are electrically connected)?

Assume a radio wave with wavelength 1 m is traveling in the negative z direction when it encounters a grid of closely spaced wires (say, 10 cm separation) laying in the xy plane, with each wire ...
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How to find the orientation of a circular polarizer without reference polarizers or molecules

It's my first time using this website, I really need your help to solve something. Also, english is not my first language so I'm sorry if I write nonsense stuff. My professor made a challange for the ...
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Mixed configuration of magneto-optical kerr effect

Typically there are three types of magneto-optical Kerr effect experiments: Polar, longitudinal, and transverse. These three geometries yield very different results regarding what is measured (...
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Why only two polarisation states of the EM wave in the Jeans cube are considered?

This question already has answers here and there. But none of them answers , why there are only two polarisation states for a mode in the Jeans cube ? I mean they only say that we take the two ...
CP of Physics 's user avatar
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Polarization tensor of graviton in $d$ dimensions

Take the following tensor, that is the sum over the two polarizations of a gravitational wave in 3 spatial dimensions: $$E_{ijkl}(\vec{k})\equiv\sum_{\lambda = +,\times} \epsilon^\lambda_{ij}(\vec{k})\...
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A question about circularly polarized light

At work, a senior colleague thinks that circularly polarized light does not exist. My problem is that we both work on a project involving polarized light. In some occasions, I would like to point out ...
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How are 3 Principle Sections possible in a crystal even when there is only one optical axis and all must contain it?

While studying polarization in calcite crystals, I came across that there are 3 possible principle sections in the rhombohedral crystal. But the conditions are that each section must be perpendicular ...
Gauransh 21HPH2625's user avatar
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How to measure the direction of circular polarization of single photons?

I just watched this video about the 2022 Nobel prize in physics which mentions the experiments that have been conducted to test Bell's inequality. In the video, they also described the experiment by ...
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Polarization-charge density in Jackson electrodynamics

I'am studying electrodynamics of Jackson. I have a question about the sect. 4.4 Boundary-Value problems with Dielectrics. There are two media($\epsilon_{1},\epsilon_{2}$) and the interface is located ...
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"Symmetric" photon polarization rotation

The usual linear polarization matrix/operator for a photon or classical light transforming from some combination of $|H\rangle$ and $|V\rangle$ to another is: $$ \begin{pmatrix} \cos(\theta) & -\...
user401228's user avatar
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Inconsistency between Jones vectors and Stokes parameters

Plane wave equation : \begin{equation} \vec{E}(z,t)=\left| \begin{array}{c} E_{0}^{x}e^{i\delta_{x}} \\ E_{0}^{y}e^{i\delta_{y}} \\ 0 \\ \end{array}\right|e^{i(\omega t -kz)}\quad,\quad E_0^{x,y} \in\...
deb2014's user avatar
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Entropy of dielectric in Capacitor?

So I am learning about dielectrics, and my professor was saying that if we connect capacitor containing dielectric to a DC source, theoretically it should produce little to no heat (the only heat ...
Kshitij Kumar's user avatar
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Direction of dipole after spontaneous emission

Consider a simple $J'= 1$ to $J = 0$ transition for an atom. If the magnetic field set the quantization along the z-direction, I am wondering what is the direction of the dipole moment after the atom ...
Lufter Rice's user avatar
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If helicity of photons is +1 then the light is right- or left-circularly polarized?

In particle physics, we say: a particle has +1 helicity (right-handed) if its momentum and spin are parallel, or it has -1 helicity (left-handed) if its momentum and spin are antiparellel. Now, if we ...
Atom63's user avatar
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What are the conditions under which these equations hold for dielectric and magnetic materials?

$E_0 = \frac{D}{\varepsilon_0}$, $E' = -\frac{P}{\varepsilon_0}$ $B_0 = \mu_0 \cdot H$, $B' = \mu_0 \cdot M$ ($E_0$ refers to the electric field generated by free charges, or the external electric ...
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How can I identify a quarter or half wave plate from a used/modified Strainoptics polarimeter?

I'm a glassblower and I need to test glass formulas for compatibility. I'd like to use a polarimeter as it allows not only the detection of strain, but also informs if a glass needs to be softer or ...
Daniel Van Antwerp's user avatar
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6 answers
872 views

Can circularly polarized light induce magnetization?

In optics, we usually consider a non-magnetic medium where the magnetization $M$ is zero, while the polarization P is proportional to the electric field $P=\epsilon_0\chi E$. $P$ is induced by some ...
Jeez's user avatar
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Is this an actual photo of frame dragging?

Is this new image (below) of polarized light surrounding Sagittarius A, showing actual frame dragging being captured by the magnetic field? The image is from this article If not, how would a photo ...
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Polarization in dielectric matter - "feedback" effect?

I'm concerned about the following scenario of polarization in a perfect dielectric: When a material is exposed to an electric field it develops polarization proportional to the electric field. From ...
Daniel's user avatar
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Deriving the Clausius-Mossotti equation for linear dielectrics from Classical Electromagnetism

I've been presented the Clausius-Mossotti equation in my Electromagnetic Optics class, but I was not given any derivation of the expression: $$\vec{P}=N\alpha \left(\vec{E}+\frac{\vec{P}}{3\...
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Stokes' vectors and quaternions

About a month ago, I was presented in my Optics class (classical and electromagnetic optics, to be more precise) the representation of partially polarised light through Stokes' vectors. Now, it ...
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Create any polarisation state with two quarter wave plates?

new to this so be kind. I have a question regarding polarisation of light. I got taught that in order to transform any arbitrary input state (fully polarised) into any arbitrary output state in ...
Sukram's user avatar
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Physical mechanisms for true depolarization of light (decrease in the degree of polarization)

I understand that complex polarization transformations (e.g., in Mie scattering) can occur without changing the technical degree of polarization (P). I'm interested in the mechanisms that specifically ...
Juan Pedro Martinez's user avatar
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2 answers
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Why intensity of unpolarised light is halved each time it passes through a polariser?

My doubt is Why is intensity halved each time an unpolarised light passes through a polaroid? My thought process is that if an unpolarised light passes through a polaroid, it will polarise the ...
satyam singh's user avatar
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If the state is VH+HV how one can prove experimentally that two photons are identical?

From a SPDC source we get two photons in a $|VH\rangle+|HV\rangle$ state. How is to be proven experimentally that they are identical while one would be in $|H\rangle$ and the other in $|V\rangle$ ...
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Why do I find different polarization vector completeness relations?

I am currently working on computing the cross section of Compton scattering in QED and in the process need to evaluate an expression of the following form: $$ \sum_{\lambda}^{} \epsilon^{\mu} (\...
MegAmaNeo1's user avatar
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$e^+e^- \rightarrow \mu^+ \mu^-$ cross section with circular polarization?

I'm trying to work through problem 5.4 of Schwartz (QFT and the Standard Model), which involves calculating the spin components of the matrix corresponding to the $e^+e^- \rightarrow \mu^+ \mu^-$ ...
rrose's user avatar
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1 answer
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Can an electromagnetic wave be polarised in the direction it propagates?

Can the electric field vector of an EM wave oscillate in the propagation direction? In text books the polarisation is always orthogonal to the propagation direction. I'm wondering specifically ...
Jorge's user avatar
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1 answer
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Isn't linearly polarised light actually chiral or am I stupid?

Isn't linearly polarised light actually chiral when taking the magnetic field into account? Just looking at the electric field is just 2D and therefore achiral, obviously. But with the magnetic field ...
Jorge's user avatar
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Graphical interpretation of complex electric fields

Before anything, I have read similar questions here but still something doesn't click perfectly, so I'll try to describe so. My doubt is essentially that I have always thought $\vec E$ in the context ...
Ivy's user avatar
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Does Slightly Polarized Refracted Light Remain Polarized after Exiting Glass?

When unpolarized light travels from air into a glass slab, the reflected light is polarized if the incident angle is equal to the Brewster angle. This is clear to me. However, according to Wikipedia, ...
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Can polarized light become unpolarized in vacuum?

Let's assume that you somehow created polarized light in a vacuum. Is there any mechanism that can make that light unpolarized down the line?
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