PRINCIPLE of laser 32

Shortly after their invention, lasers were dubbed ‘a solution looking for a problem’.
For us, today, this statement sounds totally strange and we may question how
this point of view came up. For understanding, it is worthwhile to look closer at
the process of the invention of lasers which was an exciting period not only of
technological development but also interesting personal interactions.
In 1916, when Albert Einstein published the theoretical basis with his paper on
stimulated emission, for many years the technical environment was not advanced
enough to make use of it. During theWorld War II, scientists, especially physicists,
worked in several military projects. It was not only in the ‘Manhattan Project’ to
develop the nuclear bomb, but also in projects on radar technology. When the
war was over, people with high knowledge in the generation and amplification
of microwaves continued their investigations in this field and worked on further
improvements. The limitations of classical amplifiers were obvious; in 1951,
Charles H. Townes a professor at Columbia University, New York came up with
the idea of using gas molecules and stimulated emission. The problem was solved
in 1954 by Charles H Townes who, along with James Gordon and Herbert Zeiger,
succeeded in the development of ‘Microwave Amplification by Stimulated Emission
of Radiation’, called ‘MASER’. Townes’s maser worked with ammonia and was
only a pulsed system. The concept for continuous output was first developed by
Nikolai Basov and Alexander Prokhorov of the USSR. In 1964, Basov, Prokohorov
and Townes shared the Nobel Prize in Physics for developing the maser concept.
Soon after the realization of masers, Townes together with Arthur Schawlow
investigated the possibility of optical and infrared (IR) masers. In 1957, Gordon
Gould heard about these activities from his wife Ruth who was an assistant
professor working on the some floor at Columbia University. Gould w