Red vs. Microwave/Green Light: Diffraction Patterns

[cragar]

If i shot a red laser through the top slit and microwave laser through the bottom slit
what would we expect to see in the diffraction pattern would we see a double slit pattern or a single slit pattern , how would the microwaves interfere with the red photons ,
Or if this is too extreme how about red light and green light.

 

[dulrich]

A stable interference pattern depends on the frequency from the two slits (or sources) to be of the same frequency. When two different frequencies interfere you get the phenomena of "beats". For light this would manifest itself as an oscillating intensity. But the frequency of the beat oscillation is the difference in the frequencies of the two waves which would be much too difficult to see.