All Questions
Tagged with refraction dielectric
28
questions
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
8
votes
4
answers
29k
views
Real and imaginary parts of dielectric constant vs refractive index?
So for a complex dielectric constant $\epsilon = \epsilon_a + i\epsilon_b$, the wave vector and index of refraction are related to it through $k = \frac{\omega}{c}n$ and $n = \sqrt{\frac{\mu \epsilon}{...
- 2,913
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
4
votes
2
answers
5k
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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.
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- 255
4
votes
2
answers
708
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Intuitive meaning of the permittivity and the permeability in Electromagnetism
I wonder what the correct way to intuitively understand the concepts of electrical permittivity and magnetic permeability would be.
The electric permittivity $\varepsilon$ of a medium is defined as a ...
- 974
3
votes
2
answers
134
views
Why is $c = \frac{1}{\sqrt{\mu_0 \epsilon_0}}$?
I'm sorry if this is a duplicate but I didn't find my answer. I'm currently studying maxwell's equations and I know that by comparing the wave equation for either the magnetic or the electric field
\...
- 33
3
votes
1
answer
136
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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
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
2
votes
2
answers
3k
views
Why define relative permittivity and relative permeability?
I am reading something about electomagnetic field and the first introduce the free space permittivity and permeability for the electric field and magnetic field. And later when discussing the field in ...
- 2,383
2
votes
2
answers
1k
views
Maxwell's equations, nonlinear media, and dynamic response
Maxwell's equations in the vacuum with electric permittivity $\epsilon_0$ and magnetic permeability $\mu_0$ are given as:
$$\nabla \cdot \vec E = \frac{\rho}{ \epsilon_0}$$
$$\nabla \cdot \vec B = 0$...
- 24.8k
2
votes
1
answer
204
views
Reflectivity coefficients at dielectric interface
In the book Principles of Lasers by Orazio Svelto, at chapter 4.3 "Wave Reflection and Transmission at a Dielectric Interface", the author tells that
If the wave is initially in the medium ...
- 1,904
2
votes
0
answers
27
views
Definition of the displacement field in classical field Lagrangian
In a BSM related paper (in appendix B), the authors use an effective Lagrangian $\mathcal{L}_{EFT}$, and define the following fields:
$$ \mathbf{D} = \frac{\partial\mathcal{L}_{EFT}}{\partial\mathbf{E}...
- 143
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
1
answer
3k
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Converting a complex index of refraction to a complex dielectric constant
I have a material's $n,k$ file, containing the complex index of refraction for every wavelength: $n(\omega)+ i\ k(\omega)$.
Now I would like to convert it to the dielectric constants: $\epsilon_{\...
- 111
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, ...