Understanding the Mathematical Explanation for Fresnel Lenses

In summary, Lucas has a moderate background in physics and math and is currently taking an online course to improve his understanding of optical physics. He has some doubts about how the article arrived at the five equations from the snell law.
  • #1
Lucas Olivio
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Homework Statement: what is the mathematical explanation for fresnel lenses
Homework Equations: No equations were provided

I'm going to post a link to one article I found that I think has the answer, but I couldn't understand because of my lack of knowledge in physics and math.

https://www.hindawi.com/journals/mpe/2018/4654795/
 
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  • #2
:welcome:If you have difficulty understanding the math in the link you posted, perhaps reading about Fresnel lens applications will help your understanding. This wikipedia article describes the design and history of visible light lenses.

Similar lens antennas guide microwaves in the radio frequency (RF) section of the electromagnetic spectrum. Notice the similar geometries of lighthouse lenses and microwave antennas, suggesting the underlying mathematics.
 
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(Note -- thread moved from the Homework Help forums, since it does not seem to be a homework-type question)
 
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Klystron said:
:welcome:If you have difficulty understanding the math in the link you posted, perhaps reading about Fresnel lens applications will help your understanding. This wikipedia article describes the design and history of visible light lenses.

Similar lens antennas guide microwaves in the radio frequency (RF) section of the electromagnetic spectrum. Notice the similar geometries of lighthouse lenses and microwave antennas, suggesting the underlying mathematics.
Thanks Klystron! I'll give these links a try. If more doubts come I'll make sure to post here again.
 
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  • #6
berkeman said:
Welcome to the PF, Lucas! :smile:

Can you say a bit more about your physics and math background? Have you had algebra? How about trigonometry? And have you learned about Snell's Law yet?

https://en.wikipedia.org/wiki/Snell's_law
:smile:
Thanks berkeman!
My Knowledge in these areas is moderate, my university course don't have much focus on these subjects so I end up forgetting about things. The Senll's Law I actually studied just to try solve the question, still didn't understood how the article came up with that 5 first equations only from the snell law...
In the moment I'm currently taking an online course in optical physics to be able to resolve this question, but I feel like I'm still missing something...
 

1. What is the Fresnel lens and how does it work?

The Fresnel lens is a type of lens that is made up of concentric rings or grooves on its surface. It works by bending or refracting light as it passes through these grooves, ultimately focusing the light to a single point. This allows for a thinner and lighter lens compared to traditional lenses, making it useful in various applications such as lighthouses, traffic lights, and projectors.

2. What is the mathematical concept behind the Fresnel lens?

The mathematical concept behind the Fresnel lens is based on the principle of wave interference. The grooves on the surface of the lens are designed in a way that they cancel out certain wavefronts while amplifying others, resulting in the desired focusing of light.

3. How is the focal length of a Fresnel lens determined?

The focal length of a Fresnel lens is determined by the curvature of its grooves and the distance between them. The closer the grooves are to each other, the shorter the focal length will be. This can be calculated using the formula: f = (n - 1) * d, where f is the focal length, n is the refractive index of the lens material, and d is the distance between the grooves.

4. Can the Fresnel lens be used for different types of light?

Yes, the Fresnel lens can be used for different types of light, including visible light, infrared light, and ultraviolet light. The design of the lens can be adjusted to focus different wavelengths of light, making it a versatile tool in various industries.

5. What are the advantages of using a Fresnel lens?

There are several advantages of using a Fresnel lens compared to traditional lenses. These include its lightweight and compact design, lower cost of production, and the ability to focus a large amount of light onto a small area. It is also less prone to damage and can be made with different materials for different applications.

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