The creation of Lasers in general began with creating of maser
First maser was created by Charles H. Townes in 1954.
Development of the maser was connected with military researches for radar development.
First maser was far from the perfect it’s output wasn’t continues,
but it was just the beginning.
In order to achieve continuous output, new systems with more than two energy
levels had to be designed. These systems could release stimulated emission without
falling to the ground state, thus maintaining a population inversion. Nikolai
Basov and Alexander Prokhorov of the USSR first developed this idea. Together,
Basov, Prokhorov, and Townes shared the 1964 Nobel Prize in Physics for developing
the maser concept.
Scientists began to look at the possibility of stimulated emission in other
regions of the electromagnetic spectrum. Eventually Townes, along with Arthur
Schawlow published the first detailed proposal for building an optical maser
(later to be renamed a laser) in a December 1958 issue of Physical Review.
The first laser was created by Theodore Maiman in 1960. It was "pink"
ruby rod with its ends silvered placed inside a spring-shaped flashlamp. This
laser was only capable to pulse operation.
Just before the end of 1960 (published 1961), Ali Javan, William Bennet, and
Donald Herriot made the first gas laser using helium and neon. This type of
laser (a He-Ne laser) had been the dominant laser for the next 20 years until
cheap semiconductors have appeared. In these lasers the electric discharge was
used to create lasing.
Also in the 1961 the first semiconductor laser was created by Robert Hall.
However excitement about laser began to fade, they’re called “solution
looking for a problem”. But as it often happens the military interests
helped in progress of laser development. For Vietnam war was created laser laser
radar, targeting, and reconnaissance systems. Environmental and later energy
concerns (the OPEC oil crisis) led to increased funding for laser research investigating
things such as air-pollution monitoring and energy applications.
The other reason for researching of laser technology was its attractiveness
for use in communication since the fact what the amount of coherent information
that an electromagnetic wave can carry if proportional to its frequency. Optical
light has frequencies 109 times larger than radio waves and 105 times larger
than microwaves.
In 1970 Charles Kao and George Hockham discovered that glass fibers could transmit
laser light efficiently. Also in 1970, a method was invented to improve the
p-n junctions in semiconductors which reduced the current densities needed for
semiconductor lasing from 100,000 amperes/cm2 to 8000 amperes/cm2 and then down
to 1000 - 3000 amperes/cm2. These two technologies complimented each other and
gave a new boost to laser application.
In 1975 the first semiconductor laser capable of operating continuously at the
room temperature. This event have lead us to the today’s CD-ROM, DVD-ROM,
Laser Pointers and many other useful devices.