All Questions
Tagged with optics electromagnetic-radiation
712
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What is the connection between Ray (Geometric) optics and Electromagnetic theory optics in fiber optics?
I am currently reading about fiber optics and wave propagation in fiber optics and encountered the following part of Gerd Keiser's Book :
according to the diagram shown, its a general case when the ...
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3
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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 ...
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Is it possible to optically threshold the amplitude of light waves - lower amplitude passes unaffected, higher amplitude gets lowered?
One can certainly create a digital circuit the achieves this - is it possible to do it in a purely "optical" manner?
If not with light waves, would it be possible with any other type of wave?...
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Help with dispersion relations for EM waves in anisotropic dielectric materials
I am really struggling to understand the following dispersion relations which we derived in class.
For an electric field in the z-direction, we have:
$$k^2_x + k^2_y = \frac{\omega^2}{c^2}n_z^2\tag{1}$...
- 155
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How does wetting cotton increase its UV transparency?
Anecdotally, a dry cotton T-shirt prevents sunburn better than a wet one.
This has also been measured (Gambichler et al., "Influence of wetness on the ultraviolet protection factor (UPF) of ...
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How to use the boundary conditions of electromagnetic waves to derive the refraction law of light?
In my book it says we can use the boundary conditions of electromagnetic waves to derive the refraction law of light. How to derive it?
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156
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What is an "attosecond pulse", and what can you use it for?
The 2023 Nobel Prize in Physics was announced today, and it was awarded to Pierre Agostini, Ferenc Krausz and Anne L’Huillier, for
“experimental methods that generate attosecond pulses of light for ...
- 134k
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Are Transmission values for absorptive light filters proportional to Intensity?
Mostly filter rates are given in percent, but if I imagine that for example 10 photons hit an absorption filter with 50%, molecules are excited there and in the end only 5 get through while the other ...
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Can interference occur between two consecutively arranged light filters (via reflection) in the space between them?
(This is a follow up question from my previous one: Do the values of two reflective light filters arranged one behind the other add up in this way?)
The light of the imaginary intensity 1 is viewed ...
- 211
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Can the time varying Intensity of an electric field of a wave be measured?
Lets say that we have a detector which we use to measure the intensity. Theoretically, the intensity is a varying function of time (When we calculate the Poynting vector) but often in textbooks they ...
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What happens in a conductor when the electric field has a plasma frequency?
The complex index of refraction for a conductor is given by the equation: $$N(\omega)=n+ik=\sqrt{1- \frac{\omega_p^2}{\omega^2+i\gamma\omega}} $$ where $\omega_p^2=Nq_e/\epsilon_0m_e$ is the plasma ...
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Poisson spot amplitude
The equation
$$
U(P) \propto \int_0^{2\pi} \int_0^{\infty} g(\rho,\theta) \exp\left[ \frac{i\pi}{\lambda}\left(\frac{1}{z_0} + \frac{1}{z_1}\right) \rho^2 \right] \rho \, d\rho \, d\theta
$$
or the ...
- 121
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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 ...
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What is Helicity in High Harmonic Generation?
The harmonic spectra are calculated as $|FT(\frac{d}{dt}\mathcal{J}(t))|^2$, where $FT$ si the Fourier Transform and $\mathcal{J}(t)$ is the current. We need to identify which multiple of incident ...
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Prism: full spectrum including UV + IR
When shining a white light source through a prism, one will see the spectrum of it—so a lot of colors depending on the type of light source.
However, I would also like to see the invisible part of the ...
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