The Laser Gets Ready to Turn 50
Fifty years ago Saturday, a Hughes Labs researcher named Theodore Maiman changed the world.
That day, Maiman became the first person on Earth to build a working laser, something that colleagues at a number of other companies and institutions had been feverishly trying to do for months or even years.
Coming out of World War II, explained Hughes Lab veteran and current Raytheon optics and lasers senior principal physicist Daniel Nieuwsma, many people were working with radar and were looking or ways to boost their power.
One method that was tried was using masers, or microwave amplification by stimulation of emission of radiation. Essentially, these are devices that, according to Stanford's Gravity Probe B program, set "up a series of atoms or molecules and excites them to generate the chain reaction, or amplification, of photons."
The maser was first postulated by Albert Einstein in 1917, but it wasn't until after World War II that anyone built one.
But now, in 1960, people were looking to move beyond the maser to what was being referred to as the laser--or light amplification by stimulated emission of radiation--essentially an optical maser. "Everyone was looking to make this optical maser work," Nieuwsma recalled, but Maiman "was the first to get everything together."
And on May 16 of that year, Maiman, using a flash lamp to simulate a pink ruby rod--the very first generations of lasers were solid state using a ruby crystal--crafted and used, the world's first laser.
That breakthrough has had a major ripple effect. Today, lasers are used all around the world in a wide range of industries and government agencies, from the consumer electronics to science to law enforcement, the military, entertainment, and many others. They can be small devices, like diode lasers, or huge systems with massive applications.
And it all started on May 16, 1960.
Hughes made it, but Bell Labs got the patent
While Maiman was the first to actually build a laser, he wasn't the one who got the patent for the invention. That honor went to two researchers at Bell Labs named Charles Townes and Arthur Schawlow. In 1958, after working for eight months, the two men finished a paper describing their work on the laser, despite the fact that they had not actually built one. That paper, which proposed the idea that the principles of the maser could be applied to the spectrum's optical regions, was published in the December 1958 issue of "Physical Review," notes a Bell Lab Web page on the history of the laser.
Two years later, the two men received U.S. patent No. 2,929,922 for their scholarship on the laser. Yet it was still Maiman who will go down in history as the man who invented the suddenly very much in demand technology.
According to Nieuwsma, management at Hughes--a precursor to Raytheon--had been listening to people in the field, like Schawlow, who didn't believe that the ruby was the right material for expanding the maser into the optical regions of the spectrum. But Maiman had what Nieuwsma now called a "nine-month window" and was able to finally work out how to employ a short pink ruby rod in his work.
The benefit of the ruby rod was that Maiman was able to stimulate ions in its crystal, which began to store energy. The energy turned to light and the next thing you know, Maiman had created the laser.
Defense Uses
Because Hughes was a defense contractor, management wanted to use Maiman's new invention mainly for defense-related applications, Nieuwsma recalled. First up, he said, was a 1961 project to make laser range finders that could fire a laser pulse at a distant target and make easy work of measuring the distance to the target.
As well, Hughes, in conjunction with the U.S. Army, was by the mid- to late 1960s working on laser target designators, Nieuwsma said, which allow a target to be illuminated by laser pulses which, in turn, can be focused on by a laser-homing bomb or other munition. The result, he said, was that it was now possible to very accurately blast a target.
This became incredibly important during the Vietnam war, continued Nieuwsma, when, with the help of a laser target designator, the U.S. Air Force was finally able to knock out the Thanh Hoa bridge in Vietnam, a span that it had previously attacked with 873 bombing sorties, none of which was accurate enough. In May 1972, he continued, the Air Force was finally able to destroy the bridge.
But there were also nondefense purposes that companies like Hughes and Raytheon were interested in. For example, in 1965, Nieuwsma said, Raytheon built the first laser welder, a device capable of welding multiple pieces in "very delicate welding operations" together.
Lasers were also employed in ophthalmology, for things like retinal detachment, as well as in dentistry and in surgery, because lasers can instantly cauterize a wound.
In the auto industry, lasers became an efficient and safe way to cut sheet metal, while more recently, lasers have become a mainstay of the fiber optics in the telecommunications industry. And that, according to Bob Byren, a Raytheon researcher, is because lasers are three orders of magnitude more efficient than masers. So lasers, he said, have become the backbone of the telecom industry
Mono-Chromatic
To Byren, another important element of lasers is that they are mono-chromatic. That means they are one color, a useful factor when someone is trying to pinpoint a military target. By filtering out the single color of the laser, it can be possible, using infrared cameras, to illuminate a target with a laser in such a way that those involved with the target will never know.
Another application would be for sensing chemical weapons. According to Byren, a laser puts out a single very narrow line that can be matched with the spectroscopic features of the chemical that, say, an army is trying to detect. That would be useful, Nieuwsma said, for detecting a chemical cloud coming at you.
Similarly, though, a laser could be used in a civilian case for monitoring chemical pollution coming from, say, the smokestack of a factory.
And while the very first lasers were mono-chromatic and solid state, scientists have in the years since found a way to create lasers in a range of colors and wavelengths, as well as power.
In the early days, as with Maiman's invention, a solid state laser rod was excited by a flash lamp. The laser rod itself was being excited by light, explained Byren. But then came carbon dioxide lasers where the rod could be excited by an electric discharge. And then came chemical lasers where the major element could come from a mixing of chemicals. And then came semiconductor lasers and diode lasers, new systems that relied on different materials and which could be very bright. Indeed, said Nieuwsma, for the last 20 years, diode lasers have taken the place of the flash lamp in the optical stimulation of the laser crystal.
While lasers were gaining a lot of momentum in the military and in industry and medicine in the early years, it may not have been until the 1970s that the general public got their first taste of the technology.
Oddly enough, some of the public's first experiences with lasers would have been in places like Laseriums and in the supermarket where bar code scanners became the norm.
Fifty years later, the laser has become one of the most ubiquitous elements of modern life. We may not always realize they're there, but they are. But in 1960, though the scientific world was well aware of what the technology was capable of, it still took one man--Theodore Maiman--to build the first one. And the rest is history.
