Previous page : Reflections on a metal
You can find a simulation of thin film interference on this page.
That will get you to a simple simulation of thin film interference. It looks like this
You will have three layers with different setups of index of refraction.
- The first simulates a thin film, like the surface of a soap bubble.
- The second selection is for a thin layer of air between two glass sheets.
- The third simulates anti-reflex coating on a lens.
The red curve is the incoming wave, the blue is the reflection from the first surface, and the green is the reflection from the second. What is not simulated is the changes in levels. This is to make it easier to see the relative phases. The grey curve in the separate window shows you the reflected wave, i.e. the sum of the blue and the green curves
- You can select three different selections of refractive indices.
- You can move the right boundary with the keys Q, W, E and R. Q and W move the surface to the left, Q faster and W slower, and E and R move the surface to the right, E slower and R faster.
- You can also control this with the buttons at the bottom of that page.
- You can also control this with touches on the screen to the left or right of the boundary.
- You can also click and drag/hold down to the right or left of the surface.
- You have a Pause/Resume button. The Esc key works for doing this too.
- When paused, you can move the simulation forward or back by 50 ms using the corresponding keys.
- To the simulation
I have by purpose not mentioned too much here but rather left it to you to explore. Why not try to find the conditions of destructive interference, i.e. no reflection? What are the conditions of constructive interference?
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