Ali Javan (born 27.12.1926) is an American physicist and a member of the National Academy of Sciences (1974). He was born in Tehran. He studied at the University of Tehran (1947-48). In 1948 he moved to the USA, where in 1954 he received the degree of Doctor of Philosophy. In 1958—61 he worked at the Bell Telephone Laboratories. From 1960 he has been at the Massachusetts Institute of Technology (professor from 1964).
His research is in the field of quantum electronics and its applications and of laser spectroscopy. He founded nonlinear spectroscopy. In 1960 he proposed the gas laser and built it together with W. Bennett and D. Herriott. In 1963, with C. Townes, he repeated the Michelson–Morley experiment using a helium-neon laser, and with W. Bennett and W. Lamb he found (1963) the resonant drop in the output power of a laser at the centre of the gain line (the “Lamb dip”). He constructed (1966) a theory of the effect of the crossing of modes and observed it in 1969. He developed a method of measuring the absolute frequency of a light oscillation and a method of nonlinear fluorescence (1970). He discovered the collisional narrowing of a spectral line.