Helium Neon Laser
If one wanted or needed a laser before the mid 1990s, the helium neon laser was probably the best value for a visible, continuous output low-power laser. The quality was unrivaled. Though still expensive for the time, the price was reasonable enough for the budget of a sincere laser enthusiast. As an educational tool, it had the essential features of a basic laser device: an amplifying host between a pair of mirrors, with one of the mirrors being partially transparent so that an output beam could be obtained. The mixture of helium and neon gas was excited by a high voltage electrical discharge, in a fashion that was similar to the way a neon sign worked. The beam was a lovely red color with a scintillating speckle that appeared to float around any diffuse surface from which its bright light was scattered.
It's hard for me to convey the impact this had on me as a teenager in the very early 80s, when I had the privilege of seeing my very first laser. Teachers and other students were well aware of my obsession with lasers, and this accounted for the opportunity that was afforded me when the older physics students were allowed to see the 'laser demonstration'. My geology teacher allowed me to attend, even though it was not part of her curriculum nor my course program. I suspect the year might have been around 1981 - and the experience was profoundly informative as I was allowed to witness what, up until then, I had only understood through illustrations and photographs in the aging school library books that were likely from the 60s or 70s.
It's interesting how different the perception of lasers was during that time. I remember a student once telling me (paraphrasing), 'kid, don't you know there ain't no such thing as lasers?'. At the other extreme, some members of the general public possibly perceived lasers in a manner that was not that far removed from what had been depicted in movies and science fiction television programs. I remember a man telling me about an "energy laser" (as opposed to a light laser) that had been left on by accident, allowing the laser to burn a hole through unintended targets - the identity of this 'energy laser' is today no mystery, as there are very few candidates that would have qualified in the 70s or 80s for his description, continuous Nd:YAG or CO2 being the only two I know of, with my best guess being CO2.
Not everyone perceived lasers the way they were depicted on television - there were those individuals who had been exposed to real lasers in classrooms, universities, research or industrial environments. But lasers were not commonplace in day-to-day life the way they are in the twenty-first century. The real game changer was the diode laser - once the diode laser became good enough and cheap enough to use in common applications, the use of lasers spread like wildfire. In the space of a few years, lasers were everywhere. From optical storage to fiber optics - lasers were everywhere because they were small and cheap.
