Basov, who was born in Voronezh in western Russia, served in the Soviet army in World War II, following which he graduated from the Moscow Institute of Engineering Physics (1950). He studied at the Lebedev Institute of Physics of the Soviet Academy of Sciences in Moscow, gaining his doctoral degree in 1956 and going on to become deputy director (1958) and later director (1973). In 1989 he became director of the quantum radiophysics division.

Basov's major contribution was in the development of the maser (microwave amplification by stimulated emission of radiation), the forerunner of the laser. From 1952 he had been researching the possibility of amplifying electromagnetic radiation using excited atoms or molecules. His colleague at the Lebedev Institute, Aleksandr Prokhorov, was involved in the microwave spectroscopy of gases, with the aim of creating a precise frequency standard, for use in very accurate clocks and navigational systems. Their work led to theories and experiments designed to produce a state of ‘population inversion’ in molecular beams, through which amplification of radiofrequency radiation became possible.

Together Basov and Prokhorov in 1955 developed a generator using a beam of excited ammonia molecules. This was the maser, developed simultaneously but independently in America by Charles Townes. Basov, Prokhorov, and Townes received the 1964 Nobel Prize for physics for this work.

The first masers used a method of selecting the more excited molecules from a beam, but a more efficient method was proposed by Basov and Prokhorov in 1955, the so-called ‘three-level’ method of producing population inversion by ‘pumping’ with a powerful auxilliary source of radiation. The next year the method was applied by Nicolaas Bloembergen in America in a quantum amplifier.

Basov went on to develop the laser principle, and in 1958 introduced the idea of using semiconductors to achieve laser action. In the years 1960–65 he realized many of his ideas in practical systems. He has since done considerable theoretical work on pulsed ruby and neodymium-glass lasers, which are now in common use, and on the interaction of radiation with matter. In particular, he has studied the production of short powerful pulses of coherent light.