In the late 1940s, Townes experimented with microwaves and in 1951 he constructed a device that could generate and amplify these microwaves. Based on Einstein’s theory, Townes gave his discovery the name “Maser” - an acronym for “microwave amplification by stimulated emission of radiation”. What was possible with microwaves, i.e. the amplification by stimulated emission of radiation, should also be feasible for infrared or conventional light, knowing that as the wavelength decreases, the cost of constructing a laser greatly increases
However, it was a few more years before a “light amplification by stimulated emission of radiation”, or laser in short, was actually constructed from this assumption. All material required to build a laser was known and available. A flash lamp, a synthetically manufactured ruby doped with chromium and a metal sleeve finally formed the first laser in the hands of physicist Theodore Maiman in 1960. However, experts did not pay much attention to this discovery straight away. Quite the opposite: When Maiman wanted to have his findings printed in a journal, the editors refused to accept the text - the possibility of combining coherent light beams with high color purity seemed too irrelevant, too meaningless.
Only in the course of the years did it become clear what is possible with laser technology. Nowadays ,a wide range of laser systems exists. And all are based on the principle that Einstein predicted in 1917 and Theodore Maiman experimentally demonstrated in 1960.