I know about the law of conservation of energy, and I understand interference effects conceptually, but when I put the two together I'm a little confused. I know that the energy of light must simply by transformed in destructive interference...but where does it go and how? If the interference is happening in a thin film, then the energy of the destructive interference goes to the areas of constructive interference, right? But how is this energy redistributed? Does it happen instantaneously, or at the speed of light, and if it happens at the speed of light than isn't that redistributed energy light itself...and therefore destructive interference is really just a change in the path for light so that it appears to be destructive in a certain area? Also, what about in the case of lasers pointing at each other in such a way that there is no constructive interference to speak of? In this case, where does the energy of the light go when it destructively interferes? I can understand how the values of the electric and magnetic fields will cancel, but then what happens to the photons when thinking of light as a particle? Do they just poof out of existence? Thank you for clearing this up for me!