All Questions
11
questions
0
votes
1
answer
123
views
Wave propagation in inhomogeneous media
There is a problem I'm trying to solve for some time now and is about the standard (?) approximation that it is made when one tries to solve the Helmholtz equation in inhomogeneous media, that is
\...
- 11
0
votes
1
answer
84
views
Why does the relative permittivity of Sapphire not match the square of its refractive index?
According to the Wikipedia, the refractive index of sapphire is around $n = 1.8$ while its relative permittivity $\varepsilon_{\mathrm r}$ is between $9$ and $11$ (depending on the direction). Given ...
- 329
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, ...
2
votes
1
answer
204
views
Reflectivity coefficients at dielectric interface
In the book Principles of Lasers by Orazio Svelto, at chapter 4.3 "Wave Reflection and Transmission at a Dielectric Interface", the author tells that
If the wave is initially in the medium ...
- 1,904
3
votes
0
answers
73
views
Time lag between observed electrical field and polarity of light?
I was listening to the Feynman lectures on physics Vol. 3, Ch.2 the other day, and he was talking about the relationship between light polarity and the electric field of light as it is transmitting ...
- 361
19
votes
1
answer
2k
views
How can the refractive index be below 1 in a dielectric?
Upon checking the optical properties of different dielectrics, I found the interesting case of $Al_2O_3$. It seems to be reported with a refractive index below 1 in the infrared range of $10 - 12~\mu ...
- 4,788
1
vote
2
answers
451
views
Contradiction on the behavior of refractive index
The refractive index is given by:
$$ n = \sqrt{\mu_r \epsilon_r} $$
This equation is symmetric about wavelength and is same for all wavelength of light i.e. since $\mu_r$ and $\epsilon_r$ are ...
- 39
1
vote
0
answers
141
views
Dielectric constants from refractive index and absorption spectra
I would like to calculate the dispersion relation (dielectric constants $\varepsilon'$ and $\varepsilon''$) from two spectra: refractive index $n$ and absorption (in %). I tried to use the relation $$\...
- 4,788
1
vote
0
answers
560
views
Reflection and transmission coefficients
Suppose we have a plane wave with s-polarization travelling through a medium with refractive index $n_1$ in direction $\vec{k}$ perpendicular to a surface of a dieletric with refractive index $n_2$; ...
0
votes
1
answer
2k
views
Variation of refractive index with concentration of salt in water
I know that the refractive index of water increases with increased concentration of salt.
But I also read that
$$n = \sqrt{\varepsilon_r\mu_r}$$
And that the relative dielectric constant decreases ...
6
votes
2
answers
3k
views
Refractive index of dielectric in different frames of reference
The setup
A transparent isotropic dielectric medium moving in the negative $x'$ direction at speed $v$ in frame $S'$ is stationary in frame $S$, where it has refractive index $n$. In other words, ...
- 6,425