Alexander Mikhailovich Prokhorov (born 11.08.1916) — Soviet physicist, one of the founders of quantum electronics, academician (1966; corresponding member 1960). Born in Atherton (Australia). Graduated from Leningrad University (1939). In 1946–82 he worked at the Physical Institute of the USSR Academy of Sciences (from 1954 head of the oscillations laboratory, from 1968 deputy director), and from 1982 was director of the Institute of General Physics of the USSR Academy of Sciences. From 1959 he was also a professor at Moscow University, and from 1971 head of a chair at the Moscow Institute of Physics and Technology.
His research covered quantum electronics and its applications, radiophysics, accelerator physics, radio spectroscopy, laser thermonuclear fusion, nonlinear optics and solid-state physics. He proved experimentally the coherence of the centimetre-wave radiation of the synchrotron (1951). He worked on molecular standards of frequency and time, which led him in 1954 (together with N. G. Basov) to the creation of the first molecular oscillator based on ammonia (in 1953 they had formulated the basic principles of the theory of the molecular oscillator and amplifier).
In 1955, jointly with Basov, he proposed a fundamentally new method of creating media with negative absorption — the so-called three-level method. In 1955–60 he worked on quantum paramagnetic amplifiers for the microwave range and studied a considerable number of crystals effective for use in these amplifiers; in particular, a detailed study of ruby made it possible to recommend this crystal for use in quantum oscillators and amplifiers.
In 1958 he proposed a new type of resonator for submillimetre waves — the so-called open resonator, in the form of two parallel mirror surfaces, which found wide use in laser technology.
In 1959 he was awarded the Lenin Prize, together with Basov, for developing a new method of generating and amplifying electromagnetic waves, and in 1964 the Nobel Prize was awarded to the two of them and the American physicist C. Townes for fundamental work in quantum electronics.
From 1960 Prokhorov concentrated his scientific interests on the study of the processes occurring in lasers, and on creating lasers of various types and purposes. Together with his colleagues he developed in 1963 a new operating principle for oscillators using two-quantum transitions. He built a number of continuous-wave optical oscillators, works on quantum oscillators for the infrared range of wavelengths, and constructed (1966) a new type of powerful gas laser — the gas-dynamic laser. Prokhorov's work on laser-produced high-temperature plasma contributed to the development of laser thermonuclear fusion, and his studies of the interaction of laser radiation with matter led to the discovery of a number of effects (the multifocal structure of wave beams propagating in a nonlinear medium, non-thermal resonant excitation of molecules by infrared radiation leading to their dissociation, laser generation of ultrasound in an absorbing medium, “slow burning” of a plasma near a target, and others). He is extending research in solid-state physics, in particular on the microwave properties of the plasma of a solid, on the creation of continuous ultra-strong magnetic fields, and so on.
Hero of Socialist Labour (1969). USSR State Prize (1980). Academician-secretary of the Department of General Physics and Astronomy of the USSR Academy of Sciences (from 1973), editor-in-chief of the “Great Soviet Encyclopedia” (from 1969). He founded a school of physicists. A member of a number of foreign academies of sciences and learned societies. L. I. Mandelstam Prize (1948).