Sergei Rytov
Sergei Mikhailovich Rytov () (3 July 1908 – 22 October 1996) was a Soviet physicist and member of the Russian Academy of Sciences. Rytov contributed to the fields of statistical radiophysics, and fluctuational electrodynamics. The Rytov number for laser propagation in the atmosphere and the Rytov approximation for wave propagation in inhomogeneous media bear his name. Life 
Sergei Mikhailovich Rytov was born in Kharkov, Russian Empire in 1908. Rytov graduated from Moscow State University (MGU) in 1930, and continued his studies as a post-graduate at MGU's Research Institute of Physics, which he completed in 1933. Later, Rytov worked at the Gorkiĭ Research Institute for Engineering Physics (1932–1934), the Lebedev Physical Institute (1934–1938), and finally in the Mints Institute of Radio Engineering until his death. He also lectured in MGU (1930 –1932 and 1934–1938), in the Gorkiĭ State University (1932–1934 and 1945–1947) and in the and at the Moscow Institute of Physics and Technology (1947–1978). Rytov became an expert on the theory of thermal electromagnetic radiation based on the generalization of the fluctuation-dissipation theorem. Evgeny Lifshitz was inspired by Rytov's theory to develop his theory of van der Waals forces in 1955. Rytov's work would later be summarized in a series of books Principles of Radiophysics, co-authored with Yurii A. Kravtsov Valeryan I. Tatarskii on radiophysics (Russian term for the theory of linear and nonlinear wave phenomena), where he discussed a series of topics related on fluctuation phenomena in electronic systems random fields and random propagation waves. Rytov theory would be simplified by Dirk Polder and Michael van Hove in 1971 to describe thermal radiation between closely spaced bodies. This led to the development of near-field radiative heat transfer theory, to which Rytov also contributed later. Rytov was well known for his pedagogic skills. Awards
 Three times recipient of the Order of the Red Banner of Labour
 A. S. Popov Gold Medal (1959) for a series of works in the field of statistical radiophysics. Mandeshltam Prize. Books

References 

Soviet physicists
1908 births
1996 deaths