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I understand fresnel lenses are manufactured using CNC machines. I was wondering, if it would be possible to use sound to vibrate liquid silicon and then fast cool it into the standard form of a fresnel lens? This occurred to me when I noticed that ripples on a pond resemble the lenses in question, and that certain frequencies can cause liquids to vibrate. So, hypothetically, could it be done, and if so, would it be faster than machining?

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Probably not. A fresnel lens isn't just a rippled surface, it has discontinuities, or straight edges. The area of these edges mostly causes loss of incident power. The optics designer wants a good ratio of its (aspheric) area of use to its unused area at edges.

Sound and other vibrations could create sine wave-like ripples on the surface of a liquid, but never the discontinuous shapes required to make a fresnel lens. Interesting idea, though.

cross section of a Fresnel lens

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