If you were young in the late 70s/early 80s, you may have a special appreciation for today’s subject. Remember those high-tech night club laser shows that were so popular at the time? Well, today we celebrate the invention of the laser.
On this day back in 1957, the American physicist Gordon Gould, noted down the principles of ‘Light Amplified by Stimulated Emission of Radiation’, or ‘LASER’ in a dated notebook entry. His notes also included various applications for laser light, and he was the first to coin the term ‘LASER’ at a conference in 1959.
Sadly Gould’s patenting savvy at the time didn’t match his physics skills, and his 1959 patent application was denied by the US Patent Office. The USPO subsequently went on to grant a patent in 1960 to Bell Laboratories, whose scientists, Charles Townes and Arthur Schawlow, were independently and in parallel to Gould, also working on the concept of lasers.
This effectively ‘robbed’ Gould of his share of the benefits – money, prestige, science acumen – derived from the invention. Not willing to accept this fate, Gould took the matter to court, an action that set in motion 28 years of lawsuits. He won a minor patent in 1977, but it was only in 1987 that he succeeded in achieving a major victory, claiming patents for a number of laser devices.
To this day, science historians are not in agreement about who to give primary credit for the invention of the laser, but there is no doubt that Gould deserves a large portion of the credit.
Since its discovery, many different types of lasers have been developed, producing emissions in ways too intricate to try and discuss in a blog post. However, the key feature of a laser beam is its high degree of spatial and temporal coherence. ‘Spatial coherence’ means there is very little diffraction in a laser beam, so it can be focused on a tiny spot over a significant distance. ‘Temporal coherence’ means the wave phase of the light beam is correlated over a large distance, producing a polarised wave at a single frequency.
Of course lasers are far more useful than simply creating special effects light shows. They have become a ubiquitous part of modern society, being used in electronics, information technology, medicine, industry and military applications. In any single day you may encounter lasers in barcode scanners, CD players, computer hard disks, laser printers and more.
Thanks to their precise focusing ability, lasers are used in a range of medical applications, including surgery, treatment of kidney stones, eye treatments etc. They are also used in cosmetic skin treatments. Their accurate cutting ability makes them extremely useful in many modern industrial cutting and part-making applications. They are also an integral part of many military systems, including guidance and electro-optical defence systems.
And perhaps most importantly, judging by countless science fiction movies over the years, lasers will be absolutely indispensable as the weapon of choice to defend our planet and obliterate enemy space ships!