All Questions
17
questions
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96
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How to compute the diffraction efficiency of a thin phase grating with arbitrary groove shape?
From Magnusson and Gaylord (1978), the wave amplitudes, $S_i(z)$, of $p$-polarized light for a thin, arbitrary phase grating are given by the equation
$$
\frac{\partial S_i}{\partial z} + \gamma \sum_{...
- 123
1
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0
answers
33
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Are plane waves always transverse in Fourier Optics?
In Fourier optics one decomposes the field into plane waves to find the solution of the scalar Helmholz equation. The scalar means that the electric field $\vec{E}$ is aligned towards only one ...
- 171
4
votes
2
answers
788
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How do non-periodically varying currents produce electromagnetic waves?
Electromagnetic radiation is created by the varying/accelerating of a system of charges and currents. Suppose that the time dependence of the charges and currents are $\rho(x,t)$ and $J(x,t)$. Then ...
- 324
1
vote
3
answers
214
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Why do most of the book represent Plane waves by considering a single sine or cosine wave? There should be many, right? Isn't it misrepresentation?
This Image is from Electrodynamics by Griffiths. Here also a monochromatic electromagnetic wave is considered.
- 11
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1
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84
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Is there anything special about sinusoidal EM waves? How does the strength of a purely sinusoidal EM wave vary with distance from the source?
In this atoms and sporks video, the narrator mentions that not all Electromagnetic (EM) waves have to be sinusoidal. In fact, he gives a nice animation of such a case at 16:42.
He talks about a ...
- 103
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votes
4
answers
184
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How does mixed-frequency light "remember" its component frequencies when refracting?
Combining multiple arbitrarily chosen frequencies of sound makes a complicated wave, not a new sine wave. Doesn't light also do this? If I add a 650nm (reddish) wave and a 550nm (greenish) wave, I get ...
- 191
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359
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What is the physical meaning when we say complex waveform has an energy at certain frequency?
We say that a complex periodic wave has an energy at certain frequencies.
Or we can also say that such waveform has a certain “frequency component”.
I understand that mathematically it means we can ...
- 21
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3
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845
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What Plane Waves Make a Gaussian Beam?
When I think of a light beam, what first comes to mind is this:
Black lines are axes (both spatial axes, at a snapshot in time), and blue lines represent the surfaces of constant phase of a plane ...
- 1,544
3
votes
2
answers
293
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Impossibility of Monochromatic Light [duplicate]
Pages 24-25 of my textbook, Optics by Hecht, says the following:
Using the above definitions we can write a number of equivalent expressions for the traveling harmonic wave:
$$\psi = A\sin k(x \...
- 889
4
votes
1
answer
227
views
Does there exist some other type of electromagnetic waves?
When I learned about electromagnetic waves, I was told that some accelerating charge, specifically oscillating, produces electromagnetic waves, in a way like this:
It produces a changing magnetic ...
- 364
1
vote
1
answer
943
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Rayleigh-Sommerfeld Formula: Explanation of these terms?
Can somebody explain the physical meaning of the last exponential term, $e^{j2\pi f_xx+j\pi f_yy}$, in the Rayleigh-Sommerfeld Formula?
Please correct me if I'm wrong, but I understand that $\...
- 1,325
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votes
2
answers
319
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Why is this question indicating a Fraunhofer Region rather than Fresnel Region?
I was thinking that because the source plane is infinitely large would be analogous to having the source plane being infinitely close, which would imply a Fresnel region rather than Fraunhofer.
...
- 1,325
3
votes
3
answers
8k
views
Why is electromagnetic wave (light) a sine wave?
If I remember correctly solutions to the wave equation are any periodic function. My question is related to light.
Is there a reason why light waves are sine waves?
Theoretically where do sine waves ...
- 151
1
vote
2
answers
300
views
Wave packet expression
Speaking in general about plane waves propagating along $z$ (electro-magnetic waves, for example; not necessarily particles represented as waves), a wave packet can be defined as
$$A(z,t) = \int_{\...
- 767
2
votes
0
answers
252
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Simulation of beam propagation with mirrors and lenses
I like to simulate the propagation of the wave front of an arbitrary 2d electric field. The free space propagation can be modeled in the paraxial approximation via the Fresnel equation using Fourier ...
- 358