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حمایت مالی از انجمن اپتیک و فوتونیک ایران

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انجمن اپتیک و فوتونیک ایران

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Prof Ali Javan,

Scientist and Inventor–Obituary

Ali Javan Credit: MIT Department of Physics

۲۱ September ۲۰۱۶ • ۶:۲۱pm

Ali Javan, the Iranian-born physicist and inventor, who has died aged ۸۹, was the driving force behind the invention of the first gas laser – technology that later revolutionized surgery and made possible compact-disc players and supermarket scanners; in ۲۰۰۷ he was ranked No ۱۲ on The Daily Telegraph’s list of the “Top ۱۰۰ Living Geniuses” .

Javan conceived the working principle of the gas discharge helium-neon laser in the late ۱۹۵۰s and subsequently, working at Bell Laboratories in Murray Hill, New Jersey, he led a scientific team, including William Bennett and Donald Herriott, which trapped helium and neon in a pressurised tube and agitated the gases’ atoms with an electrical current. Internal mirrors at each end of the tube redirected the resulting particles of light to send them out in a concentrated and continuous red beam.

The gas laser, which they described in the journal Physical Review Letters in ۱۹۶۱, represented a departure from an earlier laser, which derived its beam from a solid material, synthetic ruby, and was the first laser to operate on the principle of converting electrical energy to a laser light output.

Gas lasers have some advantages over those using solid materials in that they allow heat to disperse from the laser’s tube relatively quickly. Helium-neon gas lasers were the first lasers to be mass-produced, and before they were overtaken by diode-pumped solid state lasers and laser diodes, were were used in everything from checkout scanners and CD and DVD players to medical and monitoring technologies and laser printers. The gas laser also laid the foundation for fibre optic communication, a key technology used in today’s Internet and telecoms systems.

In December ۱۹۶۰, Javan made the first ever telephone call using laser beam transmission: “I put in a call to the lab. One of the team members answered and asked me to hold the line for a moment. Then I heard a voice, somewhat quivering in transmission, telling me that it was the laser light speaking to me.”

prof Ali Javan

Left to right: Donald Herriott, Ali Javan and William Bennett with the first helium-neon laser Credit: EMILIO SEGRE VISUAL ARCHIVES/AMERICAN INSTITUTE OF PHYSICS/SCIENCE PHOTO LIBRARY

Ali Javan was born in the Iranian capital, Tehran, on December ۲۶ ۱۹۲۶. His parents were Azerbaijanis originally from Tabriz; his father was a lawyer. Educated at Alborz High School, an establishment run by Zoroastrians, he started his university studies at the University of Tehran. After a year, however, he moved to Columbia University in the United States, where he took graduate courses in Physics and Mathematics and music classes with the composer Henry Cowell. After taking a PhD under Charles Townes in ۱۹۵۴, he stayed on at Columbia for four more years as a post-doctoral student researching the atomic clock.

In ۱۹۵۷ he published a paper on the theory of a three-level maser. The following year he joined Bell Laboratories shortly after conceiving the working principle of his gas discharge Helium-Neon laser.

Four years later he moved to the Massachusetts Institute of Technology as an associate professor of physics, later becoming the Francis Wright Davis Professor Emeritus of Physics. There he undertook research to expand microwave frequency-measuring techniques into the infrared, made the first accurate measurement of the speed of light and undertook research into optical electronics and nanophotonics.

Javan received numerous awards and honours for his invention of the gas laser and was a fellow of the US National Academy of Sciences, a fellow of American Academy of Art and Sciences, and an honorary associate fellow of the Third World Academy of Sciences.

Javan is survived by his wife, Marjorie, and by their two daughters.

Ali Javan, born December ۲۶ ۱۹۲۶, died September ۱۲ ۲۰۱۶

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