EN
A background for new fields of applied physics and their applications is shown, with references to and details of main discoveries, theories, experiments and technological developments in the field, made by A. Einstein (in 1916), P.Dirac (in 1927), O.Stern and M.Gerlach (in 1920), Rabi (in 1937-1939), E.Parcell and P.Pound (in 1951), A.Kastler and J.Brossel (in 1950-1951), V.Fabrikant (in 1951), C.Townes, O.Prokhorov, M.Basov and W.J.Weber (1951-1952), and by many scientists in the subsequent period. Extensive information is given about radiospectroscopy and its applications, quantum electronics (or quantum radiophysics), maser, laser (laser on the crystal of ruby, gas laser, semiconductor laser, molecular laser, other classes of lasers) and their applications, and their significance for the advancement of physics.