Alexander Mikhailovich Prokhorov was a Russian physicist and research on lasers and masers in the former Soviet Union for which he shared the Nobel Prize in Physics in 1964 with Charles Hard Townes and Nikolay Basov.
Prokhorov in 1964
Prokhorov with King Gustaf VI Adolf and wife of Townes at the Nobel Prize banquet in 1964
Basov and Prokhorov with wives in Stockholm in 1964
Alexander Prokhorov on 2016 postage stamp of Russia
A maser is a device that produces coherent electromagnetic waves (microwaves), through amplification by stimulated emission. The term is an acronym for microwave amplification by stimulated emission of radiation. First suggested by Joseph Weber, the first maser was built by Charles H. Townes, James P. Gordon, and Herbert J. Zeiger at Columbia University in 1953. Townes, Nikolay Basov and Alexander Prokhorov were awarded the 1964 Nobel Prize in Physics for theoretical work leading to the maser. Masers are used as the timekeeping device in atomic clocks, and as extremely low-noise microwave amplifiers in radio telescopes and deep-space spacecraft communication ground stations.
The first prototype ammonia maser in front of its inventor Charles H. Townes. The ammonia nozzle is at left in the box, the four brass rods at center are the quadrupole state selector, and the resonant cavity is at right. The 24 GHz microwaves exit through the vertical waveguide Townes is adjusting. At bottom are the vacuum pumps.
