|Bell Labs 1958: Arthur
L. Schawlow and Charles
H. Townes, the inventors of the maser, a device that amplifies electromagnetic
waves, created a means for the sensitive reception of communications, published
"Infrared and Optical Masers" in the American Physical Society's Physical
Review. The paper describes the basic principles of the laser, initiating
this new scientific field.
Harold Maiman invented the first operable laser while employed at Hughes
Research Laboratories as a section head in 1960. He developed, demonstrated,
and patented a laser using a pink ruby medium, for which he gained worldwide
It consisted of a ruby crystal surrounded by a helicoidal
flash tube enclosed within a polished aluminum cylindrical cavity cooled
by forced air. The ruby cylinder forms a Fabry-Perot cavity by optically
polishing the ends to be parallel to within a third of a wavelength of
light. Each end was coated with evaporated silver, one end was made less
reflective to allow some radiation to escape as a beam.
The laser was photo-pumped by a fast discharge flash-lamp,
the first ruby lasers operated in pulsed mode for reasons of heat dissipation
and the need for high pumping powers. Nelson and Boyle (1962) constructed
a continuous lasing ruby by replacing the flash lamp with an arc lamp.