THE LASER: A NEW OPTICAL RESEARCH TOOL by Philip E. Barnhart The principle of the operation of lasers has been known and understood for many years. It is perhaps one of the paradoxes of modern physics that man had only recently put the knowledge to use in view of the basic simplicity of operation and extremely wide application that results from laser action. A laser (an acronym tor Light Amplification by Stimulated Emission of Radiation) is a device based upon the processes of interaction between radiation, such as light or radio waves, and atoms or molecules. The product of a laser is coherent light, a commodity available in only limited quantities until now. Mass production of coherent light opens the door to the solutions of many problems of physical science. The laser is not a â€œdeath rayâ€? as described in some popular publications. If handled in a careless way a laser beam can do bodily harm just as the light from the sun, if not treated with proper respect, can damage the human organism.