Whoa, wait a minute…What is an interference pattern?
An interference pattern is like the waves on a pond from many different sized raindrops hitting the surface. As the circular water waves propagate outward from each impact point, the waves collide with each other, sometimes in a constructive (additive) way, creating larger waves, and sometimes in a destructive (subtractive) way, creating smaller waves or even flat surfaces. The sum total of all the waves and their interference patterns is analogous to the hologram plate.
