We have all seen a rainbow and marveled at its beauty. We like rainbows because they are pretty, they usually come at the end of storm, and they signal the breaking of dawn on a fresh day. But, rainbows are more than eye candy. They are an example of what a beam splitter can do.
The Truth About Rainbows
Most of us are familiar with the belief that there is a pot of gold at the end of a rainbow. But, we know that a rainbow is really the product of sunlight going through water droplets. The water splits the light into the different colors because light is really a combination of different colors that we normally cannot see. The water splits the light, so that makes water a kind of beam splitter. Rainbows do not really have much use except to make us feel good, but other things around us use a beam splitter.
Cameras, Light, Action
Beam splitters split regular light that goes into a camera and splits it several times in two. It produces the colors red, blue, and green that the camera processes and combines into the images we see at the end, on either a plate or other recording material. It is a bit like transporting a whole image through space, breaking it up into little bits of light very fast, and then combining them at the end so we see the whole image again.
Lasers are a little different from ordinary light. For one thing, it only has one color. When you split a laser beam, it splits into one or more beams that are exactly like the original beam but going in a different direction. Depending on the kind of beam splitter and the setup used, splitting laser beams have many uses. This includes materials processing, range finding, radar, communication via fiber optics, and medical uses.
A beam splitter is useful, and it is more common than you think. Many of us have a beam splitter in our compact disc players or optical drive. It sounds scientific, but beam splitters are as ordinary and wonderful as rainbows.