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The title is wrong. These are not Fresnel lenses, they are zone plates, which were also invented by Fresnel. As a side note, http://en.wikipedia.org/wiki/Zone
by colanderman 14y ago
The title is wrong. These are not Fresnel lenses, they are zone plates, which were also invented by Fresnel.
As a side note, http://en.wikipedia.org/wiki/Zone_plate http://en.wikipedia.org/wiki/Zone_plate makes for very interesting reading for those (such as myself) who are unfamiliar with the physics of the wave nature of light.
- iclelland 14y agoThanks for that link -- I was pretty sure that Fresnel lenses were refractive, and I ended up reading most of the article trying to reconcile the plastic lenses that I've seen with the copper diffraction grating that it seemed to be describing.
- DavidSJ 14y agoThanks, sorry about the incorrect title.