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Tagged with optics electromagnetism
596
questions
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How can Fresnel's transmission coefficient be nonzero in Total Internal Reflection?
I'm working on a problem in which a wave is moving through a transparent medium of refractive constant $n_i$. It then reaches the interface of said medium with another one of refractive constant $n_t&...
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Why the dielectric permitivity matrix of lossless media is symmetric?
I am studying optics and I met a strange statement in the section 2.3.4 (page 34) of Fundamentals of Nonlinear Optics by Peter E. Powers and Joseph W. Haus.
The relationship between $\vec{D},\ \vec{E}$...
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1
answer
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Ambiguities in optical waveguide modes
While studying concept of slab waveguide mode, I got stuck on some problems.
In textbook(Yariv chapter 3 pg 112), for guided TE modes it tells that the mode function
is taken as
which means that the ...
7
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5
answers
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Light waves can't have a wavelength
The wave nature of light comes from Maxwell's equations. More precisely, the two wave equations that come from them:
$$\Delta\vec{E}=\mu\varepsilon \frac{\partial^2\vec{E}}{\partial t^2}\\
\Delta\vec{...
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Why are Fresnel coefficients not symmetric?
When talking about reflection, we have the following coefficients for the electric field:
$$r_{\perp}=\frac{n_1\cos(i)-n_2\cos(t)}{n_1\cos(i)+n_2\cos(t)} \\ r_{\parallel}=\frac{n_2\cos(i)-n_1\cos(t)}{...
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1
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2
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72
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Why total reflection happens at only 1 angle?
The critical angle can be intuitively understood by Snell's law.If the incident medium has a bigger diffraction index than the refracted medium then according to Snell's law the refracted ray will be ...
- 101
1
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1
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Why isn't the original EM wave in a beam of light in a medium not still detectable from a distance as if it were moving at the speed of light?
I'm learning optics and I've been told that the reason light slows down in glass is because the Electromagnetic field of a beam of light interacts with and accelerates charged electrons in glass ...
- 531
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1
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Why does the energy (and thus frequency) of a photon entering glass stay constant if some is used up to accelerate electrons and slow down the light?
I'm learning optics and have been told that when light enters a medium (e.g. glass) and slows down the frequency of the light stays constant while it is the wavelength which is reduced. The ...
- 531
0
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1
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107
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Units of Poynting vector (or flux of energy) and field intensity
In optics, the Poynting vector of an EM wave is
$$\boldsymbol{\mathcal S}=\frac{c}{4\pi}\,\mathbf E\wedge\mathbf H$$
and if I am not mistaken its units in the SI system should be $\mathrm{W/m^2}$, or ...
- 296
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Metals behaving as dielectrics for certain frequencies
I'm studying the complex refractive index of material media, which is given by:
$$n_c=n+i\kappa$$
where $n$ is the refractive index and $\kappa$ is the absorption index. I interpret this as though $n$ ...
- 1,616
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0
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Physical interpretation of a dielectric's absorption curve
A given dielectric will behave as an absorbing medium for some frecuencies (those near one of the material's several resonant frequencies), whilst it will behave as a non-absorbing medium for the rest ...
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If a material is homogeneous in $\varepsilon$, can this material be made of different atoms?
I'm currently trying to derive the microscopic expression for the dielectric constant of a material following my proffessor's notes. However, he admits that, even though he assumes $\varepsilon=...
- 1,616
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24
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Trouble deducing a dipole's scattering cross section (optics)
(I've already visited this post but it begins precisely with the formula I'm trying to derive). I'm trying to deduce the scattering cross section for an electron bound to a nucleus in the far field:
$$...
- 1,616
2
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2
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84
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Dot product in optics
(Before marking this question as a duplicate, please consider I've read this post but it I didn't find the answers to it quite satisfactory regarding my doubt).
I'm trying to derive the expression of ...
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1
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Effect of incident angle on wavelength of transmitted wave for normal polarisation?
In my electrodynamcis assignment I'm being asked to derive the wavelength of a normally polarised wave transmitted through a glass/air interface as a function of $n_1$ (the refractive index of the ...
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