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I'm wondering if anyone has any analysis or sources to help me understand how a Fresnel zone plate can be implemented on a curved surface, and the corresponding diffractive efficiency and focal length??

Thanks!

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- Thread starter HEM87
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- #1

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I'm wondering if anyone has any analysis or sources to help me understand how a Fresnel zone plate can be implemented on a curved surface, and the corresponding diffractive efficiency and focal length??

Thanks!

- #2

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That's an odd question. Is there a specific application you have in mind?

- #3

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[tex]d \in \left[ \frac{(4n-1)\pi}{2 \lambda } ,\frac{(4n+1)\pi }{2 \lambda } \right], n \in \mathbb{N}[/tex]

This will produce your Fresnell pattern. All light going through these points can interfere constructively in f. The complement will produce the same effect due to Babinet's principle.

- #4

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I'm curious about using Fresbel zone plates implemented on contact lenses (RGP) for an alternative method of focusing.

So yes, I'm looking to focus light at a certain point from a plane wave, thanks deadbeef, that's useful!

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sophiecentaur

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I'm curious about using Fresbel zone plates implemented on contact lenses (RGP) for an alternative method of focusing.

So yes, I'm looking to focus light at a certain point from a plane wave, thanks deadbeef, that's useful!

Wouldn't the liquid (tears) on the surface affect the optics?

- #6

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Wouldn't the liquid (tears) on the surface affect the optics?

The tear film lens effect behind the lens is pretty well understood (generally giving a +0.25 D addition per 0.05 mm difference between corneal curvature and back RGP lens curvature) and can be corrected for generally by providing an intrinsic correction in the lens.

- #7

sophiecentaur

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That makes sense.

So the front of the fresnel lens is, in fact, smooth?

So the front of the fresnel lens is, in fact, smooth?

- #8

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That makes sense.

So the front of the fresnel lens is, in fact, smooth?

What do you mean by smooth? Planar?

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sophiecentaur

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Oh yeah, it would be smooth, just a series of opaque and transparent sections on a smooth surface.

- #11

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That's a Fresnel lens. IT is similar but not the same as the zone plates. And a Fresnel lens would really hurt your eyes.

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