Timeline for Why Does Passing Light Through a Slit Make it Coherent?
Current License: CC BY-SA 3.0
5 events
| when toggle format | what | by | license | comment | |
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| Nov 17, 2013 at 23:15 | vote | accept | CommunityBot | ||
| Nov 10, 2013 at 15:55 | comment | added | Brian Moths | The only thing you said that I take issue with is that the single slit isolates radiation from a small region of an incoherent source. All the light emitted from the surface of the source facing the single slit makes it in, but because the single slit is so narrow, if you are downstream you can't tell where the light originally came from, so it looks like the light originally came from a point source. | |
| Nov 10, 2013 at 15:51 | comment | added | Brian Moths | You raise a good point that with the setup involving an incoherent source and a single slit, the light reaching the double slits will have a short coherence time, but since the light at either slit is in phase with each other (that is the phase drifts the same way for both slits), they will still produces the desired diffraction pattern. What is important is that the waveform from the single slit is spatially coherent, which guaranteed because the single slit acts like a point. | |
| Nov 10, 2013 at 8:15 | comment | added | user26165 | Diffraction by a single slit, and double slit interference experiments were performed before laser or other coherent light sources existed. The slits do not render incoherent radiation sources coherent, nor is source coherence necessary to get either diffraction or double slit interference. The input single slit isolates radiation from a small region of an incoherent source, which ensures that the radiation arrives at the double slits phase related. The coherence length is short, but that doesn't change the phase difference at the slits. Small frequency range reduces color fringing. | |
| Nov 2, 2013 at 3:59 | history | answered | Brian Moths | CC BY-SA 3.0 |