In the 1940’s, there was a game in which you would ask someone how many motors they thought they had in their home.  The estimates were almost always much too low, as you could point out by reminding them that there were motors in such things as their wall clocks, their refrigerators, their record players, and their wristwatches.

Today, you could play the same game by asking someone how many microprocessors they think they  have1.  And soon, there will be another good topic for the game.

Theoretical mathematicians are purists.  If they learn that one of their discoveries has a practical use, they’re disappointed2.  Experimental physicists are not so snobbish:  They welcome practical applications, although they realize that their discoveries and inventions often lie fallow for a long time3.

A prime example of such a “sleeper” invention is the laser:  Developed in the 1950s as a tool for studying molecular structures, it was at first a laboratory curiosity.  A full decade passed before industrial uses were envisioned, and then highly advanced applications were postulated4.  Most of those early visions have not yet come to pass, and may never be realized.  However, what has emerged instead is a series of uses that have changed many of our lives:

You undoubtedly know about “lasik”, the laser surgery for vision correction, but lasers also have many other medical applications:  For example: there are laser scalpels, there are laser devices for removing tattoos and certain other skin blemishes, and there are lasers that enable doctors to correct some eye problems that were previously untreatable.  Lasers also can be found in major manufacturing processes.

And the laser has now moved into the home:  Do you have a CD player?  A DVD player?  A computer with a CD-ROM drive?  All of those contain lasers.  In fact, without the laser there could be none of the CDs or DVDs that bring us so much music and movies, and that store so much of our data.  “Mainframe ” and large office computer printers have used lasers for more than a decade, and the prices of smaller laser printers have now come down far enough to be attractive to home office users.

The hologram is an outgrowth of laser technology.  Holography, too, had no practical use initially.  In fact, it was referred to as “a solution looking for a problem”.  Well, like the laser it has found many problems to solve; now not only does holography have industrial applications, it is probably even in your purse or wallet:  If you have a credit card, take it out and look at it.  There is most likely a small area of the card that changes colors as you reorient it in your hand.  That is a hologram.  It makes the credit card difficult to counterfeit, and it would not be possible without the laser.

There is little doubt that lasers will find still more uses.  Truly three-dimensional movies, which are viewable from the front, back and sides, have already been produced.  And applications will certainly appear which are not yet even being thought of.

1. Most people don’t think about, in fact may not even realize, that their microwave ovens, their digital wristwatches, their digital clock radios and, if they have the most modern appliances, even their stoves, their washing machines, and their refrigerators contain microprocessors.

2. When mathematicians decided that negative numbers can be said to have square roots, they called the resulting numbers “imaginary numbers” and were convinced that imaginary numbers were of purely abstract significance.  To their horror, they saw practical uses developed in several branches of engineering and science.

3. Sometimes the eventual uses of theoretical discoveries cannot even be conceived of at first.  For instance, when the military developed a network to facilitate efficient exchange of data among scientists at major universities, they could not have anticipated that someday it would grow into the Internet and be used by a major portion of the world’s population.

4. One of the envisioned achievements that has not yet been accomplished is virtually instantaneous signal processing..