Four-wave hypersonic phase-conjugating mirrors for microsecond pulses

An experimental investigation was made of phase conjugation utilizing a four-wave interaction between light waves and hypersound for neodymium laser pulses of a few microseconds duration. These phase-conjugating mirrors made it possible to achieve lasing in an adaptive resonator where one or both mirrors was phase-conjugating, and to study its characteristics. It was found that efficient energy release from the active elements of an adaptive resonator could be achieved by using four-wave hypersonic phase-conjugating mirrors.