Texas state technical institute of Amarillo. AAS in laser electro optics technology. yes, diode lasers existed in the 70's but they were not that common. there was little use for them then, and the most common uses required a lot more energy. one of the most common at that time was the hene lasers. they were used as pointers before the diode laser began to be more user friendly. most research had been done with co2, argon and such like gas lasers. after the kinks were worked out in tunable dye lasers they were used for most of the research. oil companies frequently used co2 for the research they needed lasers for and henes were used for leveling and such. only after diode lasers became more powerful, cheaper and longer lasting did they start to replace hene in many applications. that does not make them the only type of laser existing. in fact i don't think that even today do they make up the majority of lasers. in this i could be wrong. I have not done a lot of reading up on lasers for a while, not since i could no longer work in the field.
