Who invented Laser?

Thomas Maiman, 1960

Who invented Laser ? Lasers are everywhere in modern technology. Yet initially they were just a laboratory curiosity, ‘a solution in search of a problem’. The first laser (an acronym for Light Amplification by the Stimulated Emission of Radiation) was built in 1960 by American Thomas Mainman, mostly to prove that it could be done. He used a rod of ruby, which sounds expensive and exotic, but lasers today use a wide range of solids, liquids and gases as the ‘medium’ to generate their unique radiation.

How it works ?

A laser’s talent lies in making the atoms or molecules in the medium behave in exactly the same way and at the same moment. When stimulated, all the particles release energy (in the form of light) simultaneously. Htat makes the light coherent, with the peaks and troughs of the light waves all lined up. And they all release precisely the same amount of energy, so that all the light is the one pure color. (The radiation can be invisible infrared or ultraviolet, rather than visible light, but the same properties apply.)

Coherent light has very little tendency to spread out, unlike the beam of a torch, and it can be focused into a very tight spot, less than a thousandth of a millimeter across. That makes lasers ideal for detecting the tiny marks that code information in the grooves of a CD or DVD. Tight focusing lets a laser deliver its energy into a tiny area, able, for example, to burn very tiny and perfectly formed holes in metal for precision engineering. Coherent light is also vital need in holography, a technology to give images a 3-D look.

The precise color of a laser beam means that many can be sent together down an optic fiber without confusion, greatly increasing the fiber’s capacity to carry data. It also let us measure distances with great accuracy, by timing how long a pulse of laser light takes to travel there and back. By bouncing laser beams off orbiting satellites, we know for sure that the continents are moving relative to each other at a few millimeters a year. Most likely, your builder or carpenter now uses a laser device to measure up the job.

All these are powerful applications. But in 1960, Maiman and his colleagues were not thinking about them. They just wanted the laser to work.