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Thin film interference?
How does thin film interference produce colours? I've read that it is due to interference of light reflected from the two surfaces, but surely this only affects the amplitude and therefore the intensity of the light. How does the interference of the two light waves produce different colours? There must be something which changes the frequency of the light.
Thanks
1 Answer
- Mike1942fLv 76 years ago
Sure - interference changes the frequency. You say it can only change the amplitude, but what if it changes it all the way to zero or doubles it? Effectively that means a new frequency for our eyes to see, just as we hear a "beat frequency" when sounds are different but close together. In the case of two surfaces, the phase of the interference changes with the time it takes the light to go through the thin layer of liquid and come back.
