Sound amplification by stimulated emission of radiation the axes of the mirrors, it is possible for photons to repeat multiple reflections and force more and more photons to follow them producing an avalanche effect. The number of photons of this coherent laser beam increases and competes the number of photons perished due to losses. The basic necessary condition for the generation of a laser radiation is the population inversion, which can be achieved either by exciting atoms and inducing percussion or by external radiation absorption. A SASER device mimics this procedure using a source-pump to induce a sound beam of phonons. This sound beam propagates not in
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