On August 6, 1960, Hughes Research Laboratories scientist Theodore Maiman published a study in Nature (pdf) describing his experiments with "stimulated optical radiation in ruby." (Scientific American is part of Nature Publishing Group.) With this research, he took the laser—originally "Light Amplification by Stimulated Emission of Radiation"—out of the realm of science fiction and created a tool that would change the world in ways few people could have conceived of at the time.

These possibilities tantalized many companies, including General Motors, Boeing and Raytheon, each of which has owned a piece of Hughes Research Laboratories over the past few decades. The lab, established by Howard Hughes in the 1940s to do research and development for his Hughes Aircraft Company, has since been renamed HRL Laboratories and is still jointly owned by GM and Boeing (Raytheon sold its stake in 2007).

In 1979, Daniel Nieuwsma and, later that year, Bob Byren joined Hughes Aircraft Company's Laser Engineering Division with the hope of developing new types of lasers and new ways of using the technology. Whereas Malibu, Calif.–based Hughes Research Laboratories was the company's research arm, anything that promised to have a practical application came down to Hughes Aircraft Company, located in Culver City, Calif.

The U.S. military at that time was interested in the laser for its ability to improve radar, guide long-range weapons and potentially serve as a weapon itself. However, Nieuwsma, now senior principal physicist for Raytheon Space and Airborne Systems' (SAS) Optics and Lasers Department, and Byren, principal engineering fellow and technology area director for electro-optical, infrared and laser technology at SAS, recognized the technology's potential in other areas, including communications, electronics and medicine.

Scientific American recently spoke with Nieuwsma and Byren about the laser's past, present and future.

[An edited transcript of the interview follows.]

Was the purpose for building the first laser to prove theories put forward by Einstein, Planck and other scientists regarding radiation, or did the Hughes researchers have a more practical application in mind?

Nieuwsma: Hughes' and Ted Maiman's laser work was an evolution of MASER [Microwave Amplification by Stimulated Emission of Radiation] work from the 1940s and '50s that tried to create more powerful microwave sources to improve things like the capability of radar systems. [Maiman] worked his way up to the laser [which uses light waves] as a way to get even more power.

Byren: With light, even though there are some limitations on transmission related to atmospheric conditions, you're operating on three orders of magnitude higher than microwaves in terms of frequency, with 1,000 times better resolution, meaning you can pack 1,000 times more information into light waves than into microwaves. The increase in frequency is also an advantage in bandwidth in terms of [transmitting] information. That's the whole idea behind fiber optics technology.

So the laser was not a solution in search of a problem, as has been said in the past?

Nieuwsma: When the laser was first developed no one could have possibly envisioned the number of uses we see today. Maybe that's really where the criticism of the technology came from.

Byren: It was a little bit chicken-and-egg. In the popular press, people were talking about laser weapons, and when those didn't materialize, people wondered what it could be used for. Meanwhile, in the background, scientists were working on this.

When each of you started with Hughes in 1979, what type of laser work were you doing?

Nieuwsma: I was hired to help bring in some of the lasers out of the labs and into production. Part of this was using lasers to make range finders or target designators that soldiers could use on the ground to illuminate a target for aircraft. A laser seeker attached to a bomb could fly into the illumination made by the laser. Lasers were mostly used as sensors and for precision munitions targeting to get exactly what you're aiming at more accurately.

Byren: I was already working in the field of dazzlers [which were designed to be non-lethal weapons that caused temporary blindness or disorientation]. From there, I went on to laser radar and 3-D laser imaging that could be used to guide autonomous vehicles like cruise missiles. We could use a single sensor to look at the three-dimensional outline of a target or object of interest.

When did lasers start being used for less lethal devices, and why has their use expanded so greatly over the past few decades?

Nieuwsma: Other uses for lasers started to take off in the 1970s, probably because there was a lot of government money put into the technology in the 1960s to do the core research. But, as scientists, we liked to look at different types of applications. One of the early uses was taking laser targeting technology and using it to make pictures, [the origin of what would become] laser light shows. By 1974, they were doing laser scanning of bar codes. They were doing early medical work with lasers in 1962. Raytheon developed the first laser welder in 1965, which was significant not only for welding but also for emphasizing the power of lasers and the safety issues of lasers to the government. Ophthalmology became an obvious use of lasers, using light to spot-weld the retina inside the eye. You don't want to cut the eye because it doesn't heal well. Dentistry, too, uses lasers for drilling. You can tune the laser so that it's absorbed by a dark cavity and not the white of the tooth.

What major breakthroughs enabled lasers to be used in so many other technologies, including CD players, medical equipment and fiber optics?

Byren: The first real revolution was in the number and types of lasers available [to inventors]. The semiconductor laser [also called a laser diode], developed at General Electric in 1962, allowed lasers to be scaled down in size into something very small, like what you find today in a CD player. Another innovation was the use of a number of different types of materials to make different kinds of lasers, whether they are gas lasers, free-electron lasers or solid-state lasers.

A second revolution was diode pumping, which is when you store the energy used to create the laser beam in the laser's diode crystal. Diode pumping enabled you to cut down on the amount of power needed to operate the laser and reduced the amount of heat generated, which can cause the laser to move out of alignment. Lasers became more portable because you could run them on batteries rather than a larger power source.

A third revolution was fiber lasers, which spawned the long-distance fiber optics industry. These lines contain the laser inside a flexible cable.

What are some of the hurdles that researchers are trying to overcome in developing the next generation of lasers?

Nieuwsma: The military wants every soldier to have a laser the size of a cell phone that they can use for a number of different things, such as finding distances accurately, identifying objects at a distance better, or illuminating targets on the ground that can be destroyed via unmanned aircraft. The challenge is getting enough power out of a device that small to run the laser long enough to do the job, where we are trying to take advantage of advances in energy storage and batteries made by computers and cell phones. That's kind of the low end. The high end is putting a laser into space, where it can observe the Earth very accurately to identify military targets, measure changes in the ice pack or atmosphere to observe the climate and biosphere, or even to help protect against ballistic missiles. One of the challenges there is that lasers depend, often in very subtle ways, on having an atmosphere around it, or a direction for the force of gravity, and they are often harmed by the natural radiation in space. To date, lasers have been boxed up to simulate the Earth when launched into space. Both the military and NASA would like a true space-qualified laser that does not depend on being in a protected box.

Byren: A laser [that can be positioned outside the Earth's atmosphere] certainly requires a close look at how you make the laser's different components and assemble them because once you put a laser in space, you have a long way to go to fix it if it breaks.