ABSTRACT
Lasers come in many sizes, shapes, and forms. Some lasers are as small as a grain of sand, while some large systems cover more than an acre of floor space when completely assembled. Certain lasers require toxic reactive materials, yet others need only a source of 110 V electricity (Fig. 1.1). Beams produced by some lasers have circular cross sections while other forms of beams include several small beams clustered together. Most lasers are mass produced, or “off-the- shelf,” and are readily available from manufacturers, but many are “built from scratch” for special applications. The variety of lasers appears to be limited only to the imagination of the experimentor and the application in mind. Photograph of a simple laser system requiring only 110 V electrical source for activation. Students are shown in a classroom where a low-power HeNe laser is being used. https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780203742389/f443f0c6-9406-4280-bfab-35d4111d51b2/content/fig1_1.jpg"/> (Courtesy of Hughes Aircraft, Carlsbad, California.)
