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