All Questions
7
questions
2
votes
1
answer
43
views
Why does (oxidized) aluminum have a diffuse optical appearance?
Unoxidized aluminum has a shiny appearance like typical metals. However in air aluminum rapidly oxidizes, giving it a more diffuse appearance (or bidirectional reflectance distribution function). ...
- 143
0
votes
1
answer
356
views
How can we generalize the definition a non-linear media?
According to the definition: Nonlinear media are dielectric materials whose polarization density changes nonlinearly if a strong field is applied to them. If the field is small the nonlinear terms ...
- 1,348
1
vote
0
answers
42
views
Extraordinary wave [closed]
In anisotropic media, for extraordinary wave, I don't understand how can the power flow not be in the same direction as the propagation. I can't find a physical intuition for it.
- 43
5
votes
1
answer
147
views
Difference between permittivities $\varepsilon_\text{opt}$ and $\varepsilon_\infty$?
Very often, in materials physics, we are interested in the relative permittivity at optical frequencies which is usually denoted by $\varepsilon_\text{opt}$ or $\varepsilon_\infty$.
But I'm confused ...
- 61
1
vote
1
answer
35
views
Dielectric properties of polarizing beam splitter
Are all polarizing beam splitters made up of dielectric materials?If so, what kind of dielectric materials are actually used to make them?
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
6
votes
1
answer
293
views
Why is $\textbf{D}$ the response to $\textbf{E}$?
In the text Wooten, equation 2.69 shows $\textbf{D}$ being the response to $\textbf{E}$ with $\epsilon$ as the response function:
$$
\textbf{D}(\textbf{r},t) = \int d\textbf{r}^{\prime} \int dt^{\...
- 87