Index of Refraction: Find Coating & Thickness for 600nm Wavelength

In summary, the problem involves finding the index of refraction for a coating and the required thickness given a wavelength of 600 nm and an index of refraction of 1.40 for the glass lens. The suggested solution involves using the square root of 1.4 to calculate the index of refraction for the coating and using the 'λ/4 argument' to verify the reflection coefficient at both interfaces. The calculated values are 1.183 for the coating and 126.8 nm for the thickness.
  • #1
Nymn
9
0
I'm stuck on a homework problem. It states the wavelength is 600 nm and the glass lens has an index of refraction of 1.40. Find the index of refraction for the coating and the required thickness.
I've googled around, but I'm not sure what equations I should be using. I got 1.183 for the coating (square root of 1.4) and 126.8 nm for the thickness. Is that right?
 
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  • #2
Nymn said:
I'm stuck on a homework problem. It states the wavelength is 600 nm and the glass lens has an index of refraction of 1.40. Find the index of refraction for the coating and the required thickness.
I've googled around, but I'm not sure what equations I should be using. I got 1.183 for the coating (square root of 1.4) and 126.8 nm for the thickness. Is that right?

OK, where do you get the 126nm from and what reasoning did you use? Btw, I am not saying you're wrong at all. You can verify that you are right by just going over the 'λ/4 argument' and getting the reflection coefficient equal at both interfaces.
 

1. What is the index of refraction?

The index of refraction is a measure of how much light is bent, or refracted, as it passes through a medium. It is defined as the ratio of the speed of light in a vacuum to the speed of light in the medium.

2. How is the index of refraction related to coating and thickness?

The index of refraction of a material determines how much the light will be bent as it passes through the material. Coatings with different indexes of refraction can be used to manipulate the direction and intensity of light, while the thickness of the coating also affects the amount of light that is refracted.

3. What is the significance of a 600nm wavelength?

The wavelength of light is measured in nanometers (nm) and the visible light spectrum ranges from approximately 400nm (violet) to 700nm (red). A wavelength of 600nm falls within the green-yellow range of the spectrum and is commonly used in optical applications.

4. How do you find the coating and thickness for a specific wavelength?

To find the appropriate coating and thickness for a specific wavelength, you can use the formula n = λ/λ0, where n is the index of refraction, λ is the desired wavelength, and λ0 is the reference wavelength. By rearranging the equation, you can solve for the coating and thickness needed for the desired index of refraction.

5. What factors can affect the index of refraction?

The index of refraction can be affected by various factors such as temperature, pressure, and the chemical composition of the material. In addition, the angle at which light enters the material, known as the angle of incidence, can also affect the index of refraction.

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