All Questions
Tagged with electromagnetism refraction
16
questions
85
votes
4
answers
40k
views
What is the mechanism behind the slowdown of light/photons in a transparent medium?
So light travels slower in glass (for example) than in a vacuum. What causes light to slow down? Or: How does it slow down? If light passes through the medium, is it not essentially traveling in the "...
- 1,063
4
votes
2
answers
5k
views
Can relative permittivity be less than 1?
Relative permittivity shows that force of interaction in some media is 3 times less than in vacuum ($\varepsilon = 3$) for example. When looking tables of permittivity I never saw a value less than 1.
...
- 255
2
votes
1
answer
2k
views
Light Refraction and Conservation of Momentum
When light is refracted it changes momentum in direction not magnitude.
(Now I do know it's kind of breaking the rules to take a wave described phenomena and apply particle-like theory to it. Or to ...
- 4,472
2
votes
3
answers
874
views
How Does $\epsilon$ Relate to the Dampened Harmonic Motion of Electrons?
I realize that the permittivity $\epsilon$ of a substance is easily calculated based on diffraction angles, but I am not satisfied with merely measuring it experimentally. I wish to understand its ...
- 6,044
11
votes
4
answers
2k
views
How can reflection and refraction be explained classically and microscopically?
I was trying to explain something about Brewster's angle and realized I don't completely understand how reflection and refraction work on the microscopic, classical level.
Consider a plane polarized ...
- 103k
3
votes
2
answers
3k
views
Brewster Angle - what is the polarization state of the transmitted wave?
When unpolarized light is incident at Brewster's angle, what I understand is that the reflected wave is S-polarized. What is the polarization state of the transmitted (refracted) part of the wave?
- 325
1
vote
0
answers
273
views
Effective Refractive Index in Paper
I am reading the paper, entitled "Artificial uniaxial and biaxial dielectrics with use
of two-dimensional subwavelength binary gratings" by Eric B. Grann, M. G. Moharam, and Drew A. Pommet. https://...
- 829
15
votes
2
answers
843
views
Which of these theories on why light slows in media are true?
This question is similar to previously asked questions, but the responses to them are confusing and I think it may be better covered by listing out all the potential answers for clarity.
It's a ...
- 532
9
votes
4
answers
520
views
Mathematics supporting the classical explanation of why the phase speed of light slows down in a medium
Consider the answer here by Chad Orzel which explains how a monochromatic light can slow down in a medium. He explains,
You can think each of the atoms (of the medium) as being like a little dipole,...
- 26.8k
9
votes
4
answers
2k
views
Why is the speed of light in a medium smaller than its value in vacuum?
The speed of electromagnetic waves in a medium is smaller than its value in the vacuum: $$v=\frac{1}{\sqrt{\mu\epsilon}}=c/n<c$$ with the refractive index $n=\sqrt{\frac{\mu\epsilon}{\mu_0\...
- 26.8k
4
votes
4
answers
938
views
Why does frequency remain unchanged in light refraction but wavelength doesn't? [duplicate]
Since the frequency of an electromagnetic wave does not change during refraction but the velocity changes, the wavelength must therefore change. But why doesn't the frequency change in the first place?...
- 11.8k
4
votes
2
answers
233
views
Are there any real-world examples of refraction of light by magnetic permeability?
The question Fresnel Transmission Coefficient for Magnetic Field is interesting.
Thinking about it led me to reflect upon what little I know of the history of optics, with refraction by lenses and ...
- 6,273
3
votes
1
answer
136
views
When exactly do we substitute $\epsilon_0 \rightarrow \epsilon$ and $\mu_o \rightarrow \mu $?
If everything is embedded into vacuum, why aren't Maxwells Equations always with $\mu_o$ and $\epsilon_o$?
When exactly do we have to make the substitution $\epsilon_0 \rightarrow \epsilon$ and $\...
- 1,619
3
votes
1
answer
3k
views
How to interpret the complex index of refraction?
The index of refraction which represents how much light gets refracted when entering a medium is defined as
$$n = \frac{c}{v}$$
I have seen it stated in several places, such as here, that we can ...
- 217
1
vote
2
answers
277
views
Is there a wave equation describing electromagnetic waves in materials?
Solutions to the usual wave equation for electromagnetic waves have the property that wave components of different wavelengths travel at the same phase speed $c$, so no dispersion occurs.
What I ...
- 8,640