It would have been 1964 (in third year Physics at Sydney University) that we first learnt about the MASER (Microwave Amplification by Stimulated Emission of Radiation). Coincidentally, 1964 saw the Nobel Prize in Physics awarded to Nikolay Basov and Alexander Prokhorov (who described the theory at the Lebedev Institute in 1952) and Charles H Townes (whose group built the first ammonia maser at Columbia University in 1953), “for their research in the field of stimulated emission”.
An optical version of the maser was first proposed in 1957, and originally called an “optical maser”. In the same year, 1957, Gordon Gould (working at Columbia University under Townes) is credited with coining the name “LASER”, the acronym for Light Amplification by Stimulated Emission of Radiation. Gould built his first laser in 1958, but was tardy in filing for patents, as a result of which his application was refused and the invention exploited by others. It took twenty years before the patent war was won, and Gould was finally granted patents in 1977.
The physics of the laser. Source: V1adis1av (Own work) via Wikimedia Commons
Helium-Neon laser demonstration at the Kastler-Brossel Laboratory at Paris VI: Pierre et Marie Curie. The glowing ray in the middle is a discharge tube (akin to that of a neon light), it is not the laser beam. The laser beam crosses the air and marks a red point on the screen to the right. Source: David Monniaux via Wikimedia Commons
So, in this lifetime, lasers have been proposed in theory, conceived, built and developed to the myriad of applications they now serve (for an impressive, if not exhaustive list, click here). From medicine to mining, industry to entertainment, military to domestic, lasers are part of our life today. Lasers are used to perform delicate eye surgery, to guide missiles, to cut and weld components, to read barcodes. In the home or office, lasers are used to point at a presentation slide, in the desktop printer, and to read data on CDs and DVDs. Lasers can be seen illuminating the Sydney Opera House ‘sails’ or Stone Mountain, Georgia, in a ‘laser light show’.
In fact, lasers have proliferated in ways almost unimaginable less sixty years ago.
Let us not forget the maser. Although perhaps overshadowed by its ‘offspring’, the maser is employed in astrophysics and communications. Perhaps the most important application is the use of the hydrogen maser as an atomic frequency standard and with other atomic clocks, provides the International Time standard.
