All Questions
Tagged with refraction electromagnetism
122
questions
0
votes
0
answers
105
views
Why is the refractive index $n$ linked to the wavevector $\hat{n}$?
Preamble: I'm studying light-light scattering in Effective QED but I notice that I don't remember a single thing from my EM/Optics courses so I decided to review some things.
Question: why is the ...
- 5,931
1
vote
1
answer
112
views
Where can I find tables of the refractive index (real and complex part) or dielectric function as a function of frequency for different materials?
I need this information to do simulations for my master's thesis but I don't know if there is a bibliography or a repository on the internet with this information. They are simple materials, water, ...
8
votes
3
answers
1k
views
Why does the wave velocity of EM signals in a wire depend on the insulator's permittivity?
I'm in an electromagnetism class and struggling with a concept. The textbook derived several equations which state that the wave velocity of an electrical signal in a transmission line depends on the ...
- 205
1
vote
2
answers
182
views
The operator calculation of Helmholtz equation?
I am reading the beam propagation method (BPM) in optical imaging paper. I find a paper solve the Helmholtz equation in the inhomogeneous media. The paper is:
Light propagation in graded-index optical ...
- 11
3
votes
5
answers
491
views
Variations in Refractive Index of Materials
It's quite a common fact that different types of glass have different refractive indices. Most sites I've found attribute these differences to variations in the 'density' of the glass, which is not ...
- 1,538
2
votes
0
answers
45
views
Calculating the refractive index of water with the Ewald-Oseen formula
The Ewald-Oseen theorem gives the expression
$$n=\sqrt{1+\frac{i\sigma}{\epsilon_0\omega}}$$
for the refractive index of a material of conductivity $\sigma$ for an electromagnetic wave with angular ...
- 193
0
votes
1
answer
101
views
How in Faraday rotator, changing magnetic field will change the refractive index of RCP and LCP?
Can anyone mathematically prove how in the faraday rotator, when we change the magnetic field direction, it will change the refractive index of Right circularly polarized (RCP) and Left circularly ...
1
vote
1
answer
173
views
The difference between the equation of Permittivity and Permeability in a medium
I notice that the equations of Permittivity and Permeability in a linear medium are exactly opposite of each other. One is $$\mathbf{D} \equiv \varepsilon \mathbf{E}$$ while the other one is $$\mathbf{...
- 11
2
votes
1
answer
79
views
A lens with a high permeability
In real life materials with high $\mu$ values are not realistic, so lenses are made with high $\epsilon$ materials. But what would be the impact of achieving the same refractive index by increasing $\...
- 379
1
vote
1
answer
139
views
Why Analytic in the upper hald plane required for Kramers-Kronig relations?
I've been reviewing the contents after quite a while. Now, when I'm reading Kramers-Kronig relations, I see that everywhere it is stated that the complex function have to be analytic in the upper half ...
- 141
1
vote
4
answers
214
views
How can the speed of light in matter be measured?
Experiments such as Focault's measure speed of light in matter. Focault's experimental set-up is based on the idea that it takes more time for light to travel through matter, which will result in the ...
- 1,171
1
vote
0
answers
25
views
Will changing the energy density of the vacuum alter its permitivity or permeability? [closed]
If one uses lasers or a variation of the Casimir effect to change the energy density of a region of free space, will this also change the permeability and the permittivity of this same region? Why or ...
- 609
5
votes
3
answers
1k
views
What happens to light as it enters a denser medium?
I am a first year undergrad student doing optometry (never done any physics before in my life :( ). I got a question asking what happens when light enters a denser medium. I was told that the ...
- 51
0
votes
0
answers
152
views
What is the refractive index for dilute media?
For dilute media, which I assume is a weakly absorbing medium, I have seen the refractive index $n$ given as
$$n=\sqrt{\epsilon_r}+\frac{\text{Re}\{\tilde{\chi}_e\}}{2\sqrt{\epsilon_r}},$$
where $\...
- 125
1
vote
1
answer
214
views
Appleton-Hartree Equation for different plasma wave phenomena
A lecturer referenced a plot of the refractive index squared vs the plasma frequency in relation to the Appleton Hartree equation.
In the plot it showed at different plasma frequencies the various ...