Diffraction is the deviation of waves from straight-line propagation due to an obstacle or through an aperture, without any change in their energy.
I am trying to read up on and understand diffraction. The example of a water wave under Occurrences was quite easy to understand, especially when contrasted with light waves (image below). However, aren’t the water waves losing - and thus changing - their energy as they hit the narrow entrance by losing momentum? As I said, I do understand that the waves diffract from straight lines into curved lines, but the concept of not changing energy is hard to grasp.
What would diffracted light waves look like if they did change their energy at diffraction?
vivalapivo@lemmy.today 6 days ago
You’re talking about perfect categories comparing them with the real world.
Diffraction from objects without the loss of energy doesn’t exist, but allows us to solve a simpler equation paving a way to the understanding geometry of the phenomenon.
Real world diffraction is affected by the properties of the material, mostly characterized by linear dielectric permittivity. When you start taking it into account, suddenly the light starts to penetrate into the material, often inducing heat – the primary source of the losses. Equations become messy, but it kinda allows you to calculate things with high precision.