Why did Charles H. Townes, Aleksandr Prokhorov, and Nikolay Basov receive the 1964 Nobel Prize in Physics?

Charles H. Townes, Aleksandr Prokhorov, and Nikolay Basov were awarded the 1964 Nobel Prize in Physics for their fundamental research in quantum electronics, which led to the development of the maser and the laser.123

Their work was rooted in the principle of stimulated emission, a concept first postulated by Albert Einstein in 1917. In the early 1950s, Townes, working at Columbia University, successfully demonstrated the first maser—a device capable of microwave amplification. Simultaneously and independently, Basov and Prokhorov, working at the P.N. Lebedev Physical Institute in Moscow, developed the theoretical foundations for maser operation.1432

Following these achievements, the three physicists continued their research, which provided the essential framework for extending these principles from microwave frequencies to the shorter wavelengths of infrared and visible light, resulting in the invention of the laser.123