Inventing the World's First Continuous-Wave Laser
MURRAY HILL, N.J., May 21, 2020 — 60th anniversary of the laser, Photonics Media.In December 1960, the helium-neon (HeNe) laser, the first laser to generate a continuous beam of light at 1.15 μm, was demonstrated by Ali Javan, William Bennett Jr., and Donald Herriott of Bell Labs. In the 60 years following its invention, the continuous-wave HeNe laser has been used in telecommunications, internet data transmission, holography, barcode scanners, medical devices, and more.
Javan, who was professor emeritus at MIT when he died in 2016 at the age of 89, is also credited with developing the first method for accurately measuring the speed of light and launching the field of high-resolution laser spectroscopy.
Born in Tehran, Iran, in 1926, Javan came to the U.S. in 1949, where he studied and worked at Columbia University with Nobel prize-winning physicist Charles H. Townes. Although he had received neither a bachelor’s nor a master’s degree, Javan earned his doctorate in physics at Columbia in 1954, with Townes serving as his thesis adviser.
Unlike the ruby laser — an invention that preceded the gas laser by about six months — Javan’s approach to lasing did not use optical pumping. For his HeNe laser, Javan used electric currents, not an intense light source, to convert electrical energy into the laser light output. The two laser types are quite different and are used for different purposes: An optically pumped laser creates pulsating bursts of laser light, while a gas laser produces a continuous light beam that is pure in color.
The ruby laser invented by Ted Maiman used optical pumping to create the population inversion necessary to achieve lasing. Javan discovered how a population inversion could be created in a gas discharge through the selective use of resonance energy transfer, and this was key to his invention of the first gas laser.
Javan published a paper on his concept for a gas laser in Physical Review Letters in June 1959. Although he had confidence in his invention, he knew that he had to be certain that the project would succeed before engaging a team in the engineering development phase. Soon after he joined the staff at Bell Telephone Laboratories in Murray Hill, N.J., he was given the go-ahead to do whatever was necessary to test the gas laser technology.
(Article come from www.photonics.com)