All Questions
27
questions
11
votes
4
answers
2k
views
Can the laser light, in principle, take any wavelength in the EM spectrum?
Can the laser light, in principle, take any wavelength in the EM spectrum? I don't think there is what prevent this in principle, right?
- 959
7
votes
5
answers
14k
views
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{...
- 267
1
vote
3
answers
72
views
Wavelengths of light outside our solar system
The question might have been asked before. Our Sun's rays decompose into 7 elementary colors by using a prism or spectrometry. Can the the colors (their number and wave length in the spectrum ) be ...
- 1,032
0
votes
2
answers
70
views
Why do parabolic antennas need to be the same width as their wavelength?
I am reading the wikipedia page for parabolic antennas, and have a question about the below quote:
In order to achieve narrow beamwidths, the parabolic reflector must be much larger than the ...
- 137
3
votes
3
answers
654
views
How can infrared light interact with nerve cells given the wavelength is so much longer than the cell's size?
I obviously do not understand how a wavelength greater in length than a cell can be detected by a cell.
As I understand it, infrared ranges from 300GHz to hundreds of THz.
As an example, if an ...
- 31
0
votes
1
answer
66
views
How to correctly understand wavelength of EM waves?
When we mention wavelength of EM waves, does the wavelength mean vacuum wavelength?
Is the frequency of every scalar component (x, y and z) $c/λ$, no matter whether it's linearly, elliptically or ...
- 69
0
votes
3
answers
474
views
What is the wavelength of light in a practical sense?
Okay, so I know that a wavelength is a distance of crest and a trough added together which makes a whole wave, but what is it in the real sense? Like in the case of sound I know when we say "...
1
vote
3
answers
262
views
Zero-dispersion wavelength
Please help me understanding the zero-dispersion wavelength in fibers.
I found this wiki-article on the topic. Accordingly:
"In a single-mode optical fiber, the zero-dispersion wavelength is the ...
- 113
1
vote
0
answers
416
views
Does reflection depend on wavelength?
I'm aware of processes like Rayleigh scattering, Compton scattering and pair production. But as these processes treat light as being particles(?) I'm not sure whether they are helpful to understand ...
- 1,507
0
votes
2
answers
507
views
Wavelength of light in a waveguide
I've done a derivation showing that the wave length of light in a waveguide is longer than that of free space light. But I don't really have an intuitive understanding of why this is. I think my prof ...
- 433
20
votes
8
answers
5k
views
What does the "true" visible light spectrum look like? [closed]
When I google "visible light spectrum", I get essentially the same image. However, in each of them the "width" of any given color is different.
What does the "true" ...
- 337
0
votes
2
answers
60
views
Is there any way to differentiate UV light from visible or IR light?
I'm working on a small sensor system that responds to only UV light and I wanted to know that is there any way to differentiate between UV light and the rest of the spectrum like using lens if so then ...
2
votes
3
answers
735
views
Why viruses cannot be seen?
With the coronavirus pandemic, a lot of websites are publishing articles about viruses. In particular, I've seen some of these stating that viruses cannot be seen because they are so tiny they cannot ...
- 585
0
votes
1
answer
58
views
Sun light and leaf color
Wien's displacement law :
$\lambda_{peak}T=2.898\times 10^{-3}m\cdot K$
Temp of sun = 5000
so sun radiate green wave in max volume.
but atmosphere of earth refract sun light and blue wave is max ...
- 121
0
votes
2
answers
189
views
What is considered the frequency (and wavelength) of guided waves in a waveguide?
In a rectangular waveguide with sides of length $a$ and $b$, the dispersion relation is
$$\beta^2 =\omega^2\mu\epsilon=\beta_z^2+\beta_x^2+\beta_y^2=\beta_z^2+\beta_s^2.$$
So we have
$$\beta_z = \...
- 27