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In a simplistic model, you can view destructive interference for a two-slit situation as arising from one of two possible events: Either light from a single slit is destructively interfering (and hence light from the other slit will as well, since the off-set is usually ignored), or light leaving both slits interfere with each other. The smaller "inner" ...


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The key to this kind of problem is (i) to think of a lens as a Fourier transformer and (ii) use the principle of Linear superposition. Take a look at my drawing below (it's one I drew to train people in the use of infinity conjugate optics, so don't worry about the "tested objective"). The key point here is that a point source on the focal plane of a lens ...


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The angle of the first diffracted beam (assuming we are talking about double slit, and not worrying about the width of the single slit) is $$\alpha=\frac{\lambda}{d}$$ Then we find the distance from $$\frac{spacing}{distance}=\alpha$$ So $$distance = spacing \frac{d}{\lambda}=1.5cm\frac{30\mu}{500nm}=0.9m$$ Diagram:


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What does an aperture do? It "applies" Huygens principle to every point within the aperture, and ignores those outside the aperture because they are blocked. There are a couple of things going on when you consider a lens. Let's make sure we understand them. An aperture produces a diffraction pattern in the space of diffraction angles. Recall from the ...


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For larger objects the radio wave gets reflected. Compare this to a water wave hitting a wall. For smaller objects the radio gets diffracted. Compare this to a stick placed in the path of water wave. This stick bends the water wave which is similar to diffraction A light wave consists of larger number of smaller waves. A mountain reflects most amount of ...


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You can think of Huygens's principle as a mathematical principle rather than a principle of physics. As in the Other answer, Huygens's principle can be taken to be roughly a restatement of the Kirchoff diffraction integral, and it is applicable whenever the underlying wave field fulfils the Helmholtz equation: $$(\nabla^2 + k^2)\,\psi=0$$ So it works for ...


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In EM the principle of Huygens is equivalent to Kirchhoff's formula generalized to vector fields http://en.wikipedia.org/wiki/Kirchhoff%27s_diffraction_formula which is way of expressing the diffraction field as the sum of elementary spherical waves. According to a classic explanation due to Kottler, or Stratton & Chu: Diffraction Theory of EM Waves, ...


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1) First, you said that the telescope would be > 150 mm so that atmosphere is the limit, not diffraction. But the question was, will a 114 mm scope work? Not only are you diffraction-limited, but actually coupling all of the laser power into the scope so as to get that level of collimation on the output beam is not trivial. It is true, though, that this ...



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