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| bio | website | nl.linkedin.com/in/… |
|---|---|---|
| location | Netherlands | |
| age | 31 | |
| visits | member for | 2 years, 6 months |
| seen | May 12 at 15:10 | |
| stats | profile views | 233 |
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May 12 |
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What's the physical significance of using fourier transform for diffraction? I wrote an answer about that here a while ago... |
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Apr 13 |
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Definition of frequency domain coordinates You may be interested in my answer here explaining about plane wave components, also known as spatial frequencies. |
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Feb 28 |
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Rubber band stretched produces heat and when released absorbs heat.. Why? @Nathaniel My final term freshman year project in university was to build one of those. It's been a long time so I don't remember the details, and I think I lost the project report :-P We insulated the water in a styrofoam container to keep the environment from warming it up too much, and it got quite cold to the touch. We weren't able to get it anywhere near freezing though. |
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Feb 23 |
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Optical trapping problem You've got the wrong idea about optical trapping. Or perhaps you're referring to something I've never heard of? Can you elaborate? |
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Jan 27 |
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Spectral luminous efficiency as a function of wavelength Do you have a reliable source for that? |
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Jan 4 |
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Why doesn't my pinhole camera work? +1 for doing your own experiment though! |
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Nov 19 |
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Photon energy - momentum in matter actually, three: 1) $p=\hbar k$ is only valid for a photon in a plane wave mode, which people usually gloss over; 2) saying that phase matching is due to conservation of momentum is not accurate, despite it being popular to say in nonlinear optics; 3) of course you are right that the photon is traveling mostly in vacuum and so has $p=h\nu/c$; but that expression is useless at the scale of macroscopic dielectric media. |
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Nov 19 |
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Photon energy - momentum in matter I've thought and discussed about it some more and come to two insights: |
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Nov 19 |
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Photon energy - momentum in matter Indeed, the Abraham-Minkowski controversy is divided between whether the momentum of a single photon is larger or smaller in a dielectric, but it certainly doesn't stay the same! |
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Nov 19 |
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Photon energy - momentum in matter @MarkMitchison I'm aware that photons appearing to travel slower in water is purely due to averaging. However, the momentum of a single photon is h-bar times the wave vector, and the wave vector's magnitude is larger in a denser medium with a slower speed of light. This is how phase matching works in nonlinear optics - conservation of momentum. Also, surface plasmon resonance excitation mechanisms (such as the Kretschmann configuration) are explained by different photon momenta in different materials. |
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Nov 2 |
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Are circular polarizations a basis for any light polarization? In or out of the plane of reflection when reflecting off a surface: en.wikipedia.org/wiki/… |
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Nov 2 |
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Are circular polarizations a basis for any light polarization? I think if you see people using TM and TE to mean s and p polarization, it's probably wrong (although I admit to having done this myself in the past.) |
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Nov 2 |
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Are circular polarizations a basis for any light polarization? As far as I know, TM and TE are defined in terms of waveguides. For more info, see Wikipedia: en.wikipedia.org/wiki/Waveguide_%28electromagnetism%29 |
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Nov 2 |
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Are circular polarizations a basis for any light polarization? TM and TE: not quite. If light is incident on a surface, then no transverse polarization is ever perpendicular to that surface. |
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Oct 25 |
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Ideal four-level Gain Medium (or just any old gain medium) I think you could improve your question by saying which parts you do and don't understand. |
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Oct 8 |
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Liquid crystal shutter with >90% transmission? A suggestion: as I mentioned in my answer, so much engineering goes into these things that nobody here is going to be able to help you with manufacturing strategies. Instead, why not partner with that research group at NCSU? That would benefit you both (science funding always seems to flow more readily if the funding agencies see that you are partnering with industry.) |
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Oct 8 |
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Liquid crystal shutter with >90% transmission? The second paper describes an optical filter, not a shutter. The first paper works in a different way than you describe above - instead of blocking the light with crossed polarizers and transmitting it with parallel polarizers, it doesn't block any light at all. Instead of blocking, it diverts it to the side, outside of an arbitrarily defined "viewing angle". Figure 2 of that paper is a fairly clear illustration of this. |
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Sep 25 |
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Modeling a spray painted polyurethane surface reflection Why not just spray another coat? |
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Aug 8 |
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A problem concerning the change of temperature and spectrum of a filament Could be a crappy digital camera that does not reproduce colors properly? Or the color profile got changed somehow during editing? |
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Jul 11 |
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formula for transparency of very thin film of metal For a given wavelength, you need the complex permittivity or complex refractive index of aluminum and the refractive indices of the materials on either side of the aluminum film. (See refractiveindex.info). I'll post a more extensive explanation if I have time tomorrow and nobody else has yet. |
