MgF2 Thin Film Reflection: Visible Intensification?

In summary: F2 = 4.00x10^-5 cmIn summary, a thin film of MgF2 with a thickness of 1.00x10^-5 cm is coated on a camera lens. The film has a refraction index of 1.38. The light reflected from the first surface of the film and the second surface of the film undergoes a phase change of 180 degrees, resulting in constructive interference. The wavelength of the light in the MgF2 medium must be a multiple of the thickness of the film in order to experience constructive interference. To determine the frequency of the light, the wavelength can be used.
  • #1
FizX
9
0

Homework Statement


A thin 1.00x10^-5 cm-thick film of MgF2 (n=1.38) is used to coat a camera lens. Are there any wavelengths in visible spectrum intensified in reflected light?


Homework Equations


thickness = wavelength/4n (n is refraction index)
?


The Attempt at a Solution


I am guessing that the incoming light in the material reflects inside the material to cause constructive interference at certain wavelengths (which will be multiples of the thickness of the MgF2).
My main question is, how do I relate possible wavelengths to thickness of the material?
 
Physics news on Phys.org
  • #2
FizX said:

Homework Statement


A thin 1.00x10^-5 cm-thick film of MgF2 (n=1.38) is used to coat a camera lens. Are there any wavelengths in visible spectrum intensified in reflected light?


Homework Equations


thickness = wavelength/4n (n is refraction index)
?


The Attempt at a Solution


I am guessing that the incoming light in the material reflects inside the material to cause constructive interference at certain wavelengths (which will be multiples of the thickness of the MgF2).
My main question is, how do I relate possible wavelengths to thickness of the material?
Reflection cannot add to the incident light intensity. What happens is that some frequencies are not reflected as intensely due to destructive interference within the wave coating so the frequencies which experience constructive interference appear to be more intense.

So the question is: at what frequency does the light reflected from the first surface (Air/MgF2) constructively interfere with light reflected from the second surface (MgF2/Glass).

The reflections at both surfaces undergo a phase change of 180 so these phase shifts cancel out. In order to have constructive interference, what must the path from surface 1 to 2 and back to 1 represent in terms of wavelength of the light in the MgF2 medium?

Work out the frequency of the light from the wavelength.

AM
 
  • #3


I can confirm that there will indeed be wavelengths in the visible spectrum that are intensified in reflected light from a MgF2 thin film. This is due to the phenomenon of constructive interference, where light waves reflected from the top and bottom surfaces of the film interfere with each other to produce a stronger, more intense signal. The thickness of the film, as well as the refractive index of the material, will determine which wavelengths are intensified. Using the equation provided, you can calculate the possible wavelengths that will experience constructive interference based on the thickness and refractive index of the MgF2 film. Additionally, the angle of incidence and the polarization of the light can also affect the wavelengths that are intensified. Overall, the use of a MgF2 thin film can greatly enhance the intensity of certain wavelengths in reflected light, making it a valuable tool in optical applications.
 

What is MgF2 thin film reflection?

MgF2 thin film reflection is a process in which a thin layer of magnesium fluoride is deposited onto a surface, such as glass or metal, to enhance the reflective properties of the surface. This can result in increased brightness and contrast in the visible spectrum.

How does MgF2 thin film reflection work?

MgF2 thin film reflection works by creating a thin layer of magnesium fluoride that has a refractive index closer to that of air than the surface it is applied to. This causes light to be reflected off the surface with minimal loss, resulting in increased visible intensification.

What are the benefits of using MgF2 thin film reflection?

The main benefit of using MgF2 thin film reflection is that it can significantly improve the reflectivity of a surface in the visible spectrum. This can be useful in various applications such as optical coatings, anti-reflective coatings, and solar cells.

Are there any limitations to MgF2 thin film reflection?

One limitation of MgF2 thin film reflection is that it only works for visible light. It does not enhance the reflectivity of other wavelengths such as infrared or ultraviolet. Additionally, the thickness of the film must be carefully controlled to achieve the desired reflectivity, which can be challenging.

How is MgF2 thin film reflection applied?

MgF2 thin film reflection is typically applied using a physical vapor deposition method, such as thermal evaporation or sputtering. The surface to be coated is placed in a vacuum chamber and exposed to a vapor of magnesium fluoride, which then condenses onto the surface as a thin film.

Similar threads

  • Introductory Physics Homework Help
2
Replies
35
Views
996
  • Introductory Physics Homework Help
Replies
3
Views
1K
Replies
3
Views
855
  • Introductory Physics Homework Help
Replies
1
Views
2K
  • Introductory Physics Homework Help
Replies
6
Views
3K
  • Introductory Physics Homework Help
Replies
1
Views
972
  • Introductory Physics Homework Help
Replies
7
Views
5K
  • Introductory Physics Homework Help
Replies
2
Views
2K
  • Introductory Physics Homework Help
Replies
2
Views
1K
  • Introductory Physics Homework Help
Replies
2
Views
778
Back
Top