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Amplification of light and atoms: In the optical laser, light is amplified by passing it through an excited inverted medium. In the MIT atom amplifier, an input matter wave is sent through a Bose-Einstein condensate illuminated by laser light. Bosonic stimulation by the input atoms causes light to be scattered by the condensate exactly at the angle at which a recoiling condensate atoms joins the input matter wave and augments it.

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The shadow of amplified atoms. Atom amplification is probed by sending an input beam through the atom amplifier which is a Bose-Einstein condensate (BEC) illuminated with laser light. On the left side, the input beam has passed through the condensate without amplification. 20 ms later, a shadow picture is taken of the condensate and the input atoms. When the amplification process was activated by illuminating the condensate with laser light, the output pulse contained many more atoms than the input pulse - typical amplification factors were .between 10 and 100. The field of view is 1.9 mm x 2.6 mm.

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Experimental scheme for observing phase coherent matter wave amplification. A small-amplitude matter wave was split off the condensate by applying a pulse of two off-resonant laser beams (Bragg pulse). This input matter wave was amplified by passing it through the condensate pumped by a laser beam. The coherence of the amplified wave was verified by observing its interference with a reference matter wave, which was produced by applying a second (reference) Bragg pulse to the condensate. The interference signal was observed after 35 ms of ballistic expansion. The fringes on the right side show the interference between the amplified input and the reference matter wave.