Electronics: Practical Laser

The remarkable potential of lasers (Light Amplification by Stimulated Emission of Radiation) nurtures many a heady scientific dream. Pure, one-color laser light can be focused down to a microscopic point, hot enough to burn through any material. It can make superaccurate measurements, and properly modulated, it can carry vast amounts of information. It may some day take the place of wires in the innards of computers. But all these promising applications are blocked at present by the built-in problems of existing lasers. Some of them demand costly and cumbersome power supplies; some give light of the wrong wave lengths; others can only operate at the inconvenient temperature of liquid helium. None are simple enough for handy practical use.

Now Tyco Laboratories, Inc. of Waltham, Mass., has developed a laser that seems to have the necessary simplicity. Invented by Drs. A. I. Mlavsky and L. B. Griffiths, it is a .02-in. cube of silicon carbide (carborundum), 4Two opposite sides are carefully polished, and electrodes are attached to antfcher two. When a weak direct current of electricity is passed through the cube, a thin line in its center glows with green-blue light. But this is not pure laser light. It is merely ordinary mixed-up light of varying frequencies. When the current passes a critical strength (120 amp. per sq. cm.), though, the light brightens enormously, turns intense blue, and forms an undiverging beam like a tight-stretched thread.

This is genuine laser light. And it comes from a simple rugged device that works at room temperature (no liquid helium to worry about) with no need for an expensive power source. The current demand could be supplied by flashlight batteries. Says Arthur J. Rosenberg, president of Tyco:’ “We could put it in a box the size of a pack of cards, battery and all, and signal with it. It’s as simple as that.”