Alexander Mikhailovich Prokhorov (born Alexander Michael Prochoroff, ; 11 July 1916 – 8 January 2002) was an Australian-born Russian physicist known for his pioneering research on lasers and masers in the former Soviet Union for which he shared the Nobel Prize in Physics in 1964 with Charles Hard Townes and Nikolay Basov.
Early life
Alexander Michael Prochoroff was born on 11 July 1916 at Russell Road, Peeramon, Queensland, Australia (now 322 Gadaloff Road, Butchers Creek, situated about 30 km from Atherton), to Mikhail Ivanovich Prokhorov and Maria Ivanovna (née Mikhailova), Russian revolutionaries who had emigrated from Russia to escape repression by the tsarist regime. As a child he attended Butchers Creek State School.
In 1923, after the October Revolution and the Russian Civil War, the family returned to Russia. In 1934, Prokhorov entered the Saint Petersburg State University to study physics. He was a member of the Komsomol from 1930 to 1944. Prokhorov graduated with honors in 1939 and moved to Moscow to work at the Lebedev Physical Institute, in the oscillations laboratory headed by academician N. D. Papaleksi. His research there was devoted to propagation of radio waves in the ionosphere. At the onset of World War II in the Soviet Union, in June 1941, he joined the Red Army. During World War II, Prokhorov fought in the infantry, was wounded twice in battles, and was awarded three medals, including the Medal For Courage in 1946. He was demobilized in 1944 and returned to the Lebedev Institute where, in 1946, he defended his Ph.D. thesis on "Theory of Stabilization of Frequency of a Tube Oscillator in the Theory of a Small Parameter".
Research
In 1947, Prokhorov started working on coherent radiation emitted by electrons orbiting in a cyclic particle accelerator called a synchrotron. He demonstrated that the emission is mostly concentrated in the microwave spectral range. His results became the basis of his habilitation on "Coherent Radiation of Electrons in the Synchrotron Accelerator", defended in 1951. By 1950, Prokhorov was assistant chief of the oscillation laboratory. Around that time, he formed a group of young scientists to work on radiospectroscopy of molecular rotations and vibrations, and later on quantum electronics. The group focused on a special class of molecules which have three (non-degenerate) moments of inertia. The research was conducted both on experiment and theory. In 1954, Prokhorov became head of the laboratory. Together with Nikolay Basov he developed theoretical grounds for creation of a molecular oscillator and constructed such an oscillator based on ammonia. They also proposed a method for the production of population inversion using inhomogeneous electric and magnetic fields. Their results were first presented at a national conference in 1952, but not published until 1954–1955;
In 1955, Prokhorov started his research in the field of electron paramagnetic resonance (EPR). He focused on relaxation times of ions of the iron group elements in a lattice of aluminium oxide, but also investigated other, "non-optical", topics, such as magnetic phase transitions in DPPH. In 1957, while studying ruby, a chromium-doped variation of aluminium oxide, he came upon the idea of using this material as an active medium of a laser. As a new type of laser resonator, he proposed, in 1958, an "open type" cavity design, which is widely used today. In 1963, together with A. S. Selivanenko, he suggested a laser using two-quantum transitions. For his pioneering work on lasers and masers, in 1964, he received the Nobel Prize in Physics shared with Nikolay Basov and Charles Hard Townes.