Particles of United Light
Illustration
by Michael P. Green

Have you ever wondered what makes the difference between a spotlight and a laser beam? How can a medium-power laser burn through steel in a matter of seconds, while the most powerful spotlight can only make it warm? Both may have the same electrical power requirements. The difference is unity.

A laser can be simply described as a medium of excited molecules with mirrors at each end. Some of the excited molecules naturally decay into a less excited state. In the decay process they release a photon, a particle of light. It is here that the unique process of the laser begins. The photon moves along and “tickles” another molecule, inviting another photon to join him on his journey. Then these two photons “tickle” two more molecules and invite two more photons to join the parade. Soon there is a huge army of photons marching in step with each other. It is this unity that gives the laser its power. A spotlight may have just as many photons, but each is going its own independent way, occasionally interfering with other photons. As a result, much of its power is wasted and cannot be focused to do any useful work. However, the laser, because of its unity, is like an army marching in tight formation and is able to focus all its power on its objective.

Baker Books , 1500 Illustrations for Biblical Preaching, by Michael P. Green