Tagged Questions
1
vote
0answers
26 views
Non reciprocal light propagation
In search for some explanation in why magneto-optical materials (like the one used in the Faraday rotator and, consequently, in the "optical diode") act in such a "strange" way, I saw that this kind ...
3
votes
2answers
118 views
Physical explanation for why total internal reflection occurs
I have been trying to understand total internal reflection (and have read several posts on this site already). Mathematically, I feel that I understand how the evanescent wave decays exponentially as ...
1
vote
1answer
137 views
Polarizability and the Clausius-Mossotti Relation
There seems to be a fairly large inconsistency in various textbooks (and some assorted papers that I went through) about how to define the Clausius-Mossotti relationship (also called the ...
0
votes
0answers
51 views
cgs Gauss' system of units
I had never seen this system until today, and I'm really confused. I've read the wikipedia article about it but I still don't know how to change between this and the international system. For example, ...
-1
votes
1answer
79 views
Funny classroom experiments [closed]
I'd like to perform some weekly classroom experiments to keep my students interested and curious about everyday physics. Those experiments have to be quite easy to set up and not too easy to ...
3
votes
2answers
67 views
Why is $\vec j\cdot \vec e$ the joule dissipation?
I always see $\vec j\cdot \vec e$ as Joule's dissipation and I don't understand why. For example, if we have a uniform electric field $\vec e=e_o\vec u_x$ and we release an electron in it, it will ...
1
vote
0answers
107 views
How does a Fresnel rhomb work (half and quarter wave plate)?
How does a Fresnel rhomb work (half and quarter wave plate)?
I am aware of birefringence, which creates a phase shift of $\Delta\phi=\dfrac{2\pi\Delta nL}{\lambda_0}$. But this doesn't explain how a ...
5
votes
3answers
216 views
Why is visible light used in Optical fibers (instead of other EM waves)?
Why aren't other electromagnetic waves used in optical fibres instead of visible light?
Is it because the wavelength of light fits the internal reflection/refractive index of the material used for the ...
2
votes
2answers
178 views
Irradiance (or intensity) of an electromagnetic wave
Is the irradiance (or intensity) of an electromagnetic wave given by
\begin{equation}
I = \left<\|\mathbf{S}\|\right>_{T}
\end{equation}
or by
\begin{equation}
I = ...
3
votes
1answer
77 views
How would I perceive a purple ball when traveling at relativistic speeds
I have a 'thought experiment' which I'd like to ask about.
I was thinking what speed I would have to drive towards a crossing to see a red light as a green light - pretty easy, using the doppler ...
2
votes
0answers
86 views
Bandgap Spacing in Photonic Crystals
I am doing some self-study on photonics and have encountered the following question:
We know that amorphous electronic crystals such as amorphous silicon have a bandgap. Can amorphous photonic ...
1
vote
1answer
117 views
E and H fields created by fiber optics?
When an EM wave travels down a conductor, it creates and electric and magnetic field around (H) the wire and normal to (E) the wire.
My question is, when light travels down an optical material such ...
1
vote
0answers
94 views
Is there a simple model explaining Faraday effect?
I find magneto-optical effect fascinating, and especially Faraday effect. But most sources only give a phenomenological description, while I want a deeper explanation of its mechanism. Is there a ...
0
votes
1answer
194 views
Are silicone polymers transparent to infrared light?
I know that silicon and even black plastic bags are transparent to infrared light. What about light-colored silicone polymers (take white or green colors)? Are they transparent to infrared light too? ...
2
votes
3answers
118 views
Electrial Conductivity of Thin Metal Films
What is the best way to find specific/electric conductivity which is dependent of very thin film thickness?
2
votes
1answer
59 views
In electro-optic material, what is happening to the structure of the material for the index of refraction to change?
I apologize if electro-optic material is not the correct word.
As I understand it, when an electric field is applied to an electro-optic material, the index of refraction changes in proportion to the ...
3
votes
2answers
67 views
limits on a gauss box of light
Consider a wall defined by $w(x,y,z) = \Theta(x-L)$ which is nonzero in the infinite semi-space of $x \ge L$, as well as a coherent planar standing EM wave travelling in the $z$ plane given by its ...
3
votes
3answers
329 views
formula for transparency of very thin film of metal
Is there formula that gives transparency of very thin film of given metal (tens of nanometers) to the visible light/light of given wavelength ? Which properties of metals are needed for the formula ?
...
4
votes
2answers
818 views
Make a semi transparent mirror with copper
The question:
How would you make a semi transparent mirror (50% reflection, 50% transmission) with glass with a layer of copper. For light $\lambda$ = 500nm Try to be as realistic as possible
What ...
2
votes
2answers
537 views
Does a charging capacitor emit an electromagnetic wave?
Assume you charge a (parallel plate) capacitor. This establishes an electric field (the $\mathbf E$ vector points from one plate to the other) and a circular magnetic field (the $\mathbf B$ vector ...
11
votes
3answers
611 views
Is one way glass possible?
I am not talking about mirrors, just a plain window made of glass like material. Would it be possible to allow light pass only in one direction but not the other?
6
votes
2answers
527 views
complex numbers in optics
I have recently studied optics. But I feel having missed something important: how can amplitudes of light waves be complex numbers?
I suppose this is quite fundamental, but I do not find the answer ...
3
votes
3answers
309 views
Numerical software to manipulate a light beam in its plane wave representation?
Any light field can be expressed as a sum of plane waves. Such an ensemble of plane waves is called the plane wave spectrum of the light field. The plane wave spectrum is the Fourier transform of the ...
4
votes
1answer
202 views
Question about Rayleigh scattering
To quote from Wikipedia on elastic scattering, "In this scattering process, the energy (and therefore the wavelength) of the incident photon is conserved and only its direction is changed."
How does ...
1
vote
0answers
68 views
Scaling an electron microscope to fit within 1 cubic cm when running multiple parallel scans [closed]
Yes, I'm serious.
What components correspond to an individual scan vrs what components
can be cascaded across all objects?
Ex: The vacuum chamber can be cascaded ( colocate the sample chambers ...
1
vote
1answer
72 views
Creating the opposite of an optical lattice
Is it possible to create periodic potentials that instead of creating a well for an atom to be trapped in, repulsed by that specific location?
If yes, can we use this as a means to make artificial ...
5
votes
5answers
771 views
Why aren't there compression waves in electromagnetic fields?
I just started learning about optics, and in the book I'm reading they explain how the electrical field caused by a single charged particle could be described by a series of field lines, and compare ...
1
vote
0answers
650 views
What properties of certain plastics make them x-ray transparent? [closed]
I was blown away by the abundance of good info here, and I thought maybe you could help me out with this query. I am in the process of developing a product, and I need to find a clear plastic resin ...
-4
votes
1answer
281 views
Light travels a straight line write down the principle in which this is manitested [closed]
Light traveles a straight line write down the principle in which this is manifested.
0
votes
2answers
265 views
Do and can phone signals come inside AC car which is glass-packed
Can phone signals penetrate glass, so can I expect phone signals to come if I am sitting inside a closed AC car.
Thanks,
14
votes
4answers
4k views
Why glass is transparent?
Once I asked this question from my teacher and he replied "because it passes light", "and why it passes light" I asked and he said "because it is transparent".
Same question again, Why glass is ...
11
votes
1answer
427 views
Formulation of Transformation optics using a Material Manifold
Dear Community,
recently, Transformation optics celebrates some sort of scientific revival due to its (possible) applications for cloaking, see e.g. Broadband Invisibility by Non-Euclidean Cloaking ...
3
votes
2answers
790 views
What does an atom radiate: a wave packet or a single photon?
What does an atom radiate: a wave packet or a single photon?
9
votes
4answers
549 views
Nonlinear optics as gauge theory
the widely used approach to nonlinear optics is a Taylor expansion of the dielectric displacement field $\mathbf{D} = \epsilon_0\cdot\mathbf{E} + \mathbf{P}$ in a Fourier representation of the ...
