Laser technology is a staple of science fiction and our daily lives. This 60-year-old technology continues to improve, and engineers are still developing brand new applications for lasers.
“Lasers are really hot right now,” says Carly Wright, an optical engineer who works in the laser engineering group at Northrop Grumman.
Lasers are used in medical procedures, beauty treatments, telecommunications, industrial applications, robotics, autonomous vehicles, toys, scientific research and more. Due to their power and precision, lasers are also being developed for military use.
“There’s a lot of interest in putting lasers on a wide variety of platforms to defeat a really wide variety of targets,” says Wright.
How Do Lasers Work?
Although the term “laser” is widely understood today, it was originally an acronym for light amplification by a simulated emission of radiation. A laser produces a very narrow beam of light, but it’s not just any light.
So, how do lasers work? First, you have to understand the fundamentals of light. Each color of light has a different wavelength on electromagnetic spectrum. Sunlight looks like white light, but it actually includes a mixture of all the different colors, or wavelengths of light. Lasers are different, NASA explains, because they produce a narrow beam of light in which all of the light waves have very similar wavelengths.
This alignment of waves makes laser beams narrow, bright and extremely precise. Think of a flashlight versus a laser pointer. A beam of light from a standard flashlight spreads out, but a laser pointer stays focused wherever you aim it. These properties mean laser beams can travel very long distances and concentrate their energy on a very small area.
A Brief History of Lasers
Today’s laser technology is made possible because of the fundamental principles of modern physics that Max Planck and Albert Einstein and their peers discovered in the early 1900s. According to Interesting Engineering, at the turn of the century, Planck figured out the relationship between energy and the frequency of radiation. He described that energy couldn’t just be transferred in any amount (as presumed by classical physics). Instead, energy is emitted or absorbed in discrete packets, which we now call quanta.
Einstein then expanded on Planck’s insight and proposed that “electrons could be stimulated into emitting light of a particular wavelength.” Although they weren’t specifically looking to define what is a laser, scientists continued to experiment with light over the next few decades, with the invention of holography in 1948, and the first proof of Einstein’s principles in action in 1954, with the MASER (Microwave Amplification of Stimulated Emission of Radiation).
Laser technology truly took off in the early 1960s. During this time period, the term laser was created, and the first practical laser was prototyped and patented. Scientists developed several types of lasers, including the first continuous-beam laser, the solid-state (semiconductor injection) laser, and the carbon dioxide laser. In 1961, lasers were used for medical treatment for the first time, in an optical surgery that was faster and more comfortable than conventional treatments.
Today, lasers are such a common medical tool that they are used to remove everything from tumors to unwanted hair. They’re also used in endless other facets of our lives, including telecommunications, consumer electronics, law enforcement, entertainment, manufacturing and military equipment.
Lasers in Real Life
When laser weapons are portrayed in science fiction, there’s often a bright flash of light that shoots opponents with a “pew, pew!” sound. In reality, Wright explains that lasers are stealthier than the ray gun you might be imagining. As an optical engineer, she spends most of her time working in a lab experimenting with the laser source of a direct energy (DE) weapon. Not only are lasers silent, but some are also invisible.
“The lasers that we work with, are not visible to the eye,” she says. “So when you think of laser weapons, you think of a red laser shooting through space. That’s not the case. It doesn’t make a sound.”
Make no mistake: Light, especially when concentrated in a laser, is hot and dangerous. Wright has watched a laser drill a precise hole through a brick. She works in a class 1,000 clean room, wearing a full “bunny suit” of protective gear including a mask, gown, booties, gloves and laser goggles.
In addition to their precision and power to zap objects with heat, lasers have another property that makes them a powerful weapon. Wright says, “As long as you have electricity or fuel, you can use your lasers, and there’s not a finite number of shots that you can take.” That’s particularly valuable for the naval battle space, where refueling at sea is challenging.
Despite all the awesome new technology that scientists and engineers are developing today, lasers remain a hot topic.