The duration of this flash of red light is quite brief, lasting only some 300 millionths of a second, but it is very intense. In the early lasers, such a flash reached a peak power of some 10,000 watts.
When Maiman’s device was successfully built and operating, a public relations expert was called in to help introduce this revolutionary device to the world. He took one look at the laser and decided that it was too small and insignificant looking and would not photograph well. Looking around the lab, he spotted a larger laser and decided that that one was better.
Dr. Maiman informed him in his best scientific manner that laser action had not been achieved with that one. But the world of promotion won out, and Dr. Maiman allowed the larger device to be photographed on the assumption—or was it hope?—that he would be able to get it to operate in the future. (He did.)
The device shown in [Figure 16] is the true first laser. The all-important crystal rod is seen at the center. These crystals, incidentally, must be quite free of extraneous material; hence they are artificially “grown”, as shown in [Figure 17]. The single large crystal is formed as it is pulled slowly from the “melt”, after which it is ground to size and polished.
Figure 16 Dr. Maiman’s first laser. Output was 10,000 watts.
Figure 17 An exotic crystal of the garnet family is “grown” from a melt at a temperature of 3400°F.
LASING—A NEW WORD
Now we can begin to put together the various processes and equipment we have been discussing separately. Perhaps the best way to do this is to look again at the word laser and recall its meaning: light amplification by stimulated emission of radiation. Our objective is to create a powerful, narrow, coherent beam of light. Let us see how to do this.