Take a close look at the waves the ducks are creating. The water near all of the ducks looks little like waves, but the ones farther out are very wave-like. Why don't the waves starting out near the ducks look like waves? The answer is because there are a lot of ducks, each creating separate waves from different starting locations. When they collide with each other, they interfere. The low part of one wave might hit the high part of another, causing them to cancel out and the water at that location and that instant will be neither high nor low. This interference get very complicated when there are many ducks in the water! But looking further away from the ducks, there seems to be less interference, and therefore, they look more like waves. The reason for this is because at a distance, the collection of ducks looks like a point source. Waves like this, the ones that look waves, are called coherent waves.
Thus, lasers are like ducks. Right? Well, kind of. Lasers produce coherent light waves, which is why they are bright at all distances. Lasers prevent other waves being produced inside the laser so that the light that comes out of the laser is coherent. Thus, there won't be any points in time or space where the high point of one light wave is added to the low point of another. If there were, the laser would be very dim because of all the canceling going on.
But the main point that I want to make with this post is that lasers are like cute little ducks splashing in a pond.
interesting way to look at nature. The analogy makes it really easy to understand. Good post.
ReplyDeleteThanks. I am trying to expand my audience to duck-lovers, and not just laser physicists. :)
ReplyDeleteOkay, so maybe a wee bit condescending with all the duck love, but I think the analogy works well, and that you're doing more effective science communication now. I actually think you could actually debate with laser geeks whether your analogy is correct, so your audience isn't just duck lovers, either.
ReplyDeleteNice work, Ben.
I don't mean to be condescending... just a little humorous. I think the contrast between ducks and lasers makes people wonder what I am talking about with my title. I grab their attention with the title and the seemingly pointless video before I tell the reader to take a closer look. Maybe the realization that the video actually has a point will make the reader think more critically about everyday events and how they relate to other, more complicated ideas.
ReplyDelete