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The history of the laser

You are listening to the VOA Special English program EXPLORATIONS.

The physics of the laser may be complex. Still, it is just a story of how electrons interact with light. When a light particle, or photon, hits an electron, the electron jumps to a higher energy state. If another photon strikes one of these high-energy electrons, the electron releases two photons that travel together at the same wavelength. When this process is repeated enough, lots of organized, or coherent, photons are produced.

In Theodore Maiman’s first laser, a rod of man-made ruby supplied the electrons. A more powerful version of the flash on a common camera was used to lift the energy state of the electrons. Mirrors on either end of the ruby rod reflected and increased the light. And an opening at one end of the rod let the laser light shoot out — just like the flash ray of science fiction hero Buck Rogers.

Industry put lasers to work almost immediately after they were invented in nineteen sixty. But weapons were not first on the list.

The first medical operation using a laser took place the year following its invention. Doctors Charles Campbell and Charles Koester used a laser to remove a tumor from a patient’s eye at Columbia-Presbyterian Hospital in New York City. Since then, doctors have used lasers to cut and remove tissue safely with little risk of infections.

Other health uses include medical imaging and vision correction surgery. Eye surgeons use lasers in LASIK operations to reshape the cornea, which covers the lens of the eye. The reshaped cornea corrects the patient’s bad eyesight so he or she does not have to wear glasses or other corrective lenses.