Albert Einstein (1879–1955) was the first to envision the intense, powerful beams of light we know today as lasers. In 1917, he wrote that if atomic particles called photons were combined and energized in a certain way, they would emit light all in the same direction and frequency—as opposed to ordinary visible light, which is very scattered. It took several decades, however, for physicists to find out exactly how to make this technique work.

In 1954, the researchers James Gordon and Charles Townes (1915–) used microwave rays to generate the first “microwave amplification by stimulated emission of radiation,” or maser, at Columbia University. Townes continued to work with Arthur Schawlow (1921–1999) at Bell Labs on a prototype device with mirrors on either side of its cavity so that photons of the desired wavelength could bounce back and forth. Four years later, calculations for a light maser, or laser, were published.

The medical community saw great potential in these lasers, although difficulty controlling the power output and delivery of early laser systems led to inconsistent and disappointing results in early human studies. One area where lasers did seem to have promise was eye surgery. In 1964, an easy-to-control, high-absorption argon ion laser was developed, and clinical systems soon became available for the treatment of retinal disease.

Also that year came the development of a carbon dioxide (CO2) laser, which emitted an easily focused infrared beam that was well absorbed by water. Because the human body consists mainly of water, doctors found that a CO2 laser beam could cut tissue like a scalpel—but with much less blood loss, since the beam’s heat immediately cauterized the tissue.

By the early 1970s, teaching hospitals were using CO2 lasers for sinus and gynecologic surgeries. In another 10 years, laser surgery became widespread, and smaller but more powerful devices began appearing in hospitals and even doctors’ offices for everything from making laparoscopic surgical incisions to removing tattoos and birthmarks. Lasers today are also widely used for cosmetic surgery, including skin resurfacing, hair removal, and the treatment of varicose leg veins, among other procedures.

ADDITIONAL FACTS

  1. Today, dentists can use lasers to detect early-forming cavities.
  2.  Scientists at MIT are studying how a laser and a light-activated dye may be able to help heal surgical wounds and prevent scarring.
  3.  The first laser was created with a synthetic ruby crystal and produced a bright red light called a ruby laser.