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Aleksandr Prokhorov is known for his experimental work in radio physics and microwave spectroscopy. He developed the maser, which is a device that amplifies electromagnetic waves by stimulated emission of radiation. The maser is used in many applications, including radar, telecommunications, and medical imaging. Prokhorov shared the Nobel Prize in Physics in 1964 with Charles Townes and Nikolai Basov for their work on the maser.