As the latter part of the acronym implies, it works by pumping energy into electrons of atoms in some substance, called the gain material. But unlike Moore’s Law, which has resulted from continuous incremental improvements in chip-manufacturing technology, the increase in lasers’ peak power has been the result of a few major breakthroughs in laser technology.Ī laser is largely an amplifier, as the “a” in laser signifies: Light Amplification by Stimulated Emission of Radiation. This power increase is much like the increase in the density of solid-state electronics described by the famous Moore’s Law-the number of transistors in an integrated circuit doubles about every two years. The peak power attainable in a laser pulse has increased by roughly a factor of 1,000 every 10 years. The enormous increase in lasers’ peak power through the past 50 years has been mind boggling. Even Maiman’s first laser was pulsed and likely had a peak power of a few hundred watts (about the same power used by an average toaster oven today). In fact, the high powers possible with pulsed-laser light were apparent from the very earliest days of laser development.

Pulsed lasers find application in lofty tasks, such as the production of controlled nuclear fusion and laser eye surgery, down to the mundane, such as cosmetic hair removal. Because power is defined as energy delivered per unit of time, when the energy emerging from the laser in a pulse of light increases and the time duration of the pulse decreases, the instantaneous power during the pulse-described more accurately as “peak power”- increases. This is indeed the case for the miniature lasers that read compact discs or the barcode scanners in supermarkets, but there is a large class of lasers that deliver light in short pulses. One often thinks of lasers as delivering a continuous beam of light in one color that is well collimated (meaning the photons in the beam remain parallel and don’t diverge from each other). But one of the most fascinating subplots in the story of laser development since 1960 has been the astonishing increase in the power that lasers can deliver. The 50-year history of laser development since this first demonstration has had numerous twists, including the 30-year patent battle that surrounded the laser’s invention.

This year marks the 50th anniversary of the demonstration of the first laser, a feat performed by Theodore Maiman in his laboratory at Hughes Aircraft Company in 1960. Lasers now find widespread application in an incredibly diverse range of duties, including reading compact discs, printing paper, scanning bar codes, machining and welding, precision surgery, finding distances, enabling high-speed communications, guiding precision munitions and driving controlled nuclear fusion.

Laser pulse faster than light