All Questions
27
questions
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23
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What is meant by optical density?
I’m trying to research about optical density for a school task, but the definitions online are confusing me.
From what I’ve gotten, optical density is:
how much the intensity of light is increased or ...
0
votes
0
answers
46
views
How can a greater than 1 reflectance coefficient be explained in $\rm SiC$-$\rm SiO_2$ interface?
I ran a simulation using the Transfer Matrix Method to plot the R,T and A curves for a SiC->SiO2 interface. There's a region of incident energies where the |r|^2 I get is higher than 1 and the ...
- 11
1
vote
1
answer
56
views
Do mirrors (with metal surfaces) show TIR (Total Internal Reflection)?
[Not a duplicate! Also, the answer to a similar question was unsatisfactory]
I was digging into why we don't use mirrors in place of fibre optics cables. Majorly, the answers were as follows:
It's ...
- 153
4
votes
1
answer
684
views
How do optical fibres work with high critical angles?
The critical angle is given by:
c = arcsin(n2 - n1)
For a typical optical fibre, it says on the web that refractive index (n2) for cladding is higher than that of the glass core (n1) but it's only a ...
- 153
3
votes
1
answer
462
views
Brewster's angle for Metal?
As metal has a high refraction index, it is possible to have Brewster's Angle for Metal when the light incident from the air? Is it possible to derive from any formula?
- 41
1
vote
1
answer
215
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How does reflectance change with wavelength? [duplicate]
Sorry if this is an easy question, I am new to physics and this field.
I have a question about reflectance which i believe to be "effectiveness of reflecting radiating energy"
My goal is to ...
- 11
2
votes
0
answers
149
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What can be the possible causes for variation in stress-induced birefringence in an isotropic material?
Birefringence is the phenomenon of a material having a refractive index that depends on the polarization and propagation direction of light. When an unpolarized light passes through such a material, ...
- 21
3
votes
5
answers
491
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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
0
votes
1
answer
3k
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Obtaining both relative permittivity and permeability from refractive index
The complex refractive index $\tilde{n}$ is related to the relative electric permittivity and the magnetic permeability with the relation
\begin{equation}
\tilde{n} = n + \mathrm{i} k= \sqrt{\...
- 2,302
1
vote
4
answers
214
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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
2
votes
1
answer
138
views
How to control the refractive index of semiconductors?
I keep seeing/hearing that the refractive index can be controlled in semiconductors, but every time I read something like that it's always something very specific, like "Refractive index ...
1
vote
2
answers
408
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Why does $\rm TiO_2$ require less thickness for thin-film interference than light wavelength suggests?
TL;DR: Why does titanium oxide layer produce visible thin-film interference at thicknesses 10x smaller than the wavelengths of light?
Background:
I am currently trying to model thin film interference ...
36
votes
4
answers
5k
views
Why are the edges of a broken glass almost opaque?
Unfortunately I broke my specs today which I used in this question.
But I observed that the edges are completely different then the entire part of the lens. The middle portion of the lens was ...
- 8,230
4
votes
1
answer
251
views
How does a broadband dielectric Mirror work?
It is widely known that dielectric mirrors work with several layers of at least two materials which differ in refractive index that are layered, such that partially reflected waves interfere ...
- 139
0
votes
1
answer
130
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Example of inverse relationship between density and refractive index across different materials
I'm aware that refractive index usually correlates with density. I'm curious to know if there are strong counter examples to this rule.
In particular I'm interested to know if there is a pair of ...
- 103