Ali Javan

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Ali Javan
علی جوان
Javan ali.jpg
Born (1926-12-26) December 26, 1926 (age 97)
Tehran, Iran
Nationality Iranian American
Fields Physicist
Institutions Columbia
Bell Labs
MIT
Alma mater Columbia
University of Tehran
Doctoral advisor Charles Townes
Doctoral students Michael S. Feld
Known for Gas laser
Lasing without inversion
Laser spectroscopy
Timing frequency of light
Atomic coherence
Notable awards Stuart Ballantine Medal (1962)
Albert Einstein World Award of Science (1993)

Ali Javan (Persian: علی جوان‎‎ - Ali Javān, Azerbaijani: [æli d͡ʒaβɑn]; born December 26, 1926) is an Iranian-American physicist and inventor at MIT. His main contributions to science have been in the fields of quantum physics and spectroscopy. He co-invented the gas laser in 1960, with William R. Bennett.[1] In 2007 Javan was ranked Number 12 on the list of the "Top 100 Living Geniuses".[2]

Life and career

Ali Javan was born in Tehran to Azerbaijani parents from Tabriz.[3] His parents sent him to a school conducted by Zoroastrians.[4] He graduated from Alborz High School, and started his university studies at the School of Science at the University of Tehran for a year. During a visit to New York in 1948, he attended some graduate courses at Columbia University. He received his Ph.D. in 1954 under his thesis advisor Charles Townes without having received a bachelor's or master's degree.[5] In 1955 Javan held a position as a Post Doctoral in the Radiation Laboratory and worked with Townes on the atomic clock research, and used the microwave atom beam spectrometer to study the hyperfine structure of atoms like copper and thallium.

In 1957 he published a paper on the theory of a three-level maser,[6] and his discovery of the stimulated Raman effect that a Stokes-shifted Raman transition can produce amplification without requiring a population inversion.[7][8] The effect was the precursor of a class of effects known as Lasers Without Inversion, or the LWI effect.[9] He joined Bell Telephone Laboratories in 1958 shortly after he conceived the working principle of his gas discharge Helium Neon laser, and subsequently submitted his paper for publication which was reviewed by Samuel Goudsmit in 1960.[10][11]

At MIT in the early 1960s, Ali Javan started a research project aimed at extending microwave frequency-measuring techniques into the infrared. He introduced the concept of an optical antenna of several wavelengths long which enables the near-complete confinement of an incident optical field coupled to it, and forming the antenna in nanoscale. For the first time an antenna was used to receive light and to transmit it to an infinitesimal receiving structure at its tip, observable only with an electron microscope.[12] The antenna responded to infrared laser light and generated current vibrating at the frequencies of the incident beams. It would send electrons streaming into the oxide layer which offers resistance, converting the AC signals to DC and also generating a beat that can be observed electronically. Using this method Javan developed the first absolutely accurate measurement of the speed of light.[13]

Javan carried out the first demonstration of optical heterodyne beats with lasers in 1961.[14][15] Another major experiment was his observation of the detuning dip called the Lamb dip while scanning the frequency of a single-mode laser across the Doppler-broadened gain profile.[16] In 1964 Javan and Townes devised experiments using lasers to test special relativity including a variant of the Michelson-Morley ether drift experiment to study the anisotropy of space.[17]

In 1966 Ali Javan and Theodore Maiman split a cash award presented to them by President Johnson honoring their work.[18] In 1971 he had flown back to Iran where he met and talked with the former Shah of Iran, and was the director of the first symposium on lasers held in Isfahan.[19]

Javan first worked at Massachusetts Institute of Technology as an associate professor of physics in 1961 and has remained Francis Wright Davis Professor Emeritus of physics since 1964. He continued researching into the area of "optical electronics", which envisions scaling electronic elements in such a way that they would be capable of handling frequencies as high as visible optical radiation frequencies.[20]

He is married and has two daughters with his wife Marjorie.

The gas laser

The gas laser was the first continuous-light laser and the first laser to operate "on the principle of converting electrical energy to a laser light output." By definition, "a gas laser is a laser in which an electric current is discharged through a gas to produce light." Ali Javan received U.S. patent #3,149,290 together with William Bennett for the "Gas Optical Maser". Ali Javan first tested his invention on December 12, 1960.

Laser beam transmission

On December 13, 1960, the first telephone conversation using laser beam transmission occurred. Ali Javan describes the moment: "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 [Mr. Balik], somewhat quivering in transmission, telling me that it was the laser light speaking to me."[21]

Importance of the gas laser

The gas laser laid the foundation for fiber optic communication. Laser telecommunication via fiber optics is known to be the key technology used in today's Internet.[22] Helium-Neon gas lasers were the first lasers to be mass-produced. They were used in everything from UPC checkout scanners, video disc players to medical and monitoring technologies and laser printers. Although they have been largely replaced by diode-pumped solid state lasers and laser diodes, they are now used principally for specialized applications such as interferometry and holography due to their long coherence length and Gaussian irradiance profile.

Honors

See also

References

Notes

  1. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  2. ↑ "Top 100 living geniuses" Daily Telegraph (28 October 2007)
  3. ↑ "Ali Javan" on the Farhangsara website
  4. ↑ Smithsonian Magazine April 1971, Ali Javan and his 40 lasers, page 43
  5. ↑ Smithsonian Magazine 1971, page 43
  6. ↑ Javan, A. Theory of a 3-Level Maser, Physical Review, 1957
  7. ↑ Javan, A. Transitions a Plusieurs Quanta Et Amplification Maser Dans Les Systemes a Deux Niveaux, Journal De Physique Et Le Radium, 1958
  8. ↑ Ali Javan interviewed by Jeff Hecht, on Feb 28, 1985. Lasers and Applications
  9. ↑ MIT Web Page of Ali Javan. Biographical Sketch.
  10. ↑ Interview with Ali Javan by Lee Sullivan at the Optical Society of America, Boston, Massachusetts (September 4, 2008)
  11. ↑ Javan, Herriott and Bennett, Population Inversion and Continuous Optical Maser Oscillation in a Gas Discharge Containing a He-Ne Mixture, Physical Review Letters, 1961
  12. ↑ Smithsonian Magazine April 1971, How Ali Javan's antenna receives light, page 46
  13. ↑ Javan, Ali. "Measurement of the Frequency of Light". Annals of the New York Academy of Sciences (February 1969)
  14. ↑ Interview with Ali Javan by Lee Sullivan at the Optical Society of America, Boston, Massachusetts (September 4, 2008) "[...]with Ed Ballik, the two of us saw the very first experiment done with lasers, a significant experiment showing the color purity of it, heterodyning them [two free running lasers]. The very first paper published by Optical Society is just that. [...]"
  15. ↑ Javan, Ballik, Frequency Characteristics of a Continuous-Wave He-Ne Optical Maser, Journal of the Optical Society of America (1962)
  16. ↑ Haken, Hermann. Laser Theory, Springer, 1984. pp. 199. ISBN 3540121889
  17. ↑ Jaseja, Javan, Murray, Townes, Test of Special Relativity or of Isotropy of Space by Use of Infrared Masers, Physical Review a-General Physics (1964)
  18. ↑ U.P.I. United Press International photo archives, 4/27/66
  19. ↑ Smithsonian Magazine, April 1971, Ali Javan and his 40 lasers, page 46
  20. ↑ Javan, Ali with Blair, Betty. "Scientists Who Made A Difference: Ali Javan, The Gas Laser and Beyond", Azerbaijan International, Vol. 4:2 (Summer 1996), "[...] I'm now working in a new area that I call "Electronics at Optical Frequencies." Computers, for example, use microchips that operate at radio frequencies-MHz (Mega-Hertz) and GHz (Giga-Hertz). I'd like to take electronics out of radio frequency into the light wave frequency range. [...]"
  21. ↑ Javan, Ali with Blair, Betty. "Scientists Who Made A Difference:Ali Javan, The Gas Laser and Beyond", Azerbaijan International, Vol. 4:2 (Summer 1996), pp. 14-18
  22. ↑ "Iran holds 1st fully domestic laser exhibit" on the Press TV website (February 28, 20120)
  23. ↑ Lua error in package.lua at line 80: module 'strict' not found.

Bibliography

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External links

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