Sergei Mikhailovich Rytov (born 03.08.1908) is a Soviet physicist and a corresponding member of the USSR Academy of Sciences (1968). Born in Kharkov. Graduated from Moscow University (1930). In 1934–58 he worked at the Physical Institute of the USSR Academy of Sciences. From 1958 he was at the Radio Engineering Institute of the USSR Academy of Sciences, and in 1947–78 also professor at the Moscow Institute of Physics and Technology.
His research was in the field of the theory of oscillations, acoustics, the propagation of radio waves, electrodynamics, statistical radiophysics and optics. He obtained (1938–63) fundamental results in the theory of self-oscillations of systems of the Thomson type, in the theory of the diffraction of light by ultrasound, in the theory of betatron and synchrotron oscillations, in geometrical optics, and in the theory of parametric oscillators and amplifiers. He proposed (1938) an effective method of analysing the construction of waves in smoothly inhomogeneous media (Rytov's method). He developed (1953–67) the general theory of thermal fluctuations in electrodynamics. He constructed (1970) a general relaxation theory of the spectral composition of molecular light scattering.
He founded a school of physicists. The A. S. Popov Gold Medal (1959), the L. I. Mandelstam Prize (1948).