Sound amplification by stimulated emission of radiation of the laser. In a SASER device, a source (e.g., an electric field as a pump) produces sound waves (lattice vibrations, phonons) that travel through an active medium. In this active medium, a stimulated emission of phonons leads to amplification of the sound waves, resulting in a sound beam coming out of the device. The sound wave beams emitted from such devices are highly coherent. The first successful SASERs were developed in 2009. Instead of a feedback-built wave of electromagnetic radiation (i.e., a laser beam), a SASER delivers a sound wave. SASER may also be referred to as "phonon laser",
James A. Abrahamson retrieval and repair mission. Abrahamson was appointed by President Ronald Reagan to be the first director of the Strategic Defense Initiative ("SDI") in April 1984. The "Star Wars" program, as SDI's detractors dubbed it, was initiated to develop a sophisticated anti-ballistic missile system that would prevent missile attacks from other countries, particularly the Soviet Union. Some countries opposed to U.S. missile defense efforts raised concerns about the program "contravening" the anti-ballistic missile (ABM) of the Strategic Arms Limitation Talks in years before the program was enacted. Ultimately, concerns about the objectives of SDI and fiscal budgetary constraints forced the Reagan