Manipulating Bose-Einstein condensates with laser light

A dilute gas Bose-Einstein condensate was probed and manipulated by off-resonant laser beams. Spontaneous and stimulated off-resonant light scatterings were studied experimentally. Stimulated, two-photon Bragg scattering was used for spectroscopic measurement of the mean-field energy and of the intrinsic momentum uncertainty of the condensate. The high momentum and energy resolution of this method allowed the determination of the coherence length of the condensate, which was shown to be equal to its size. Spontaneous, off-resonant Rayleigh scattering was studied by exposing an elongated condensate to a single off-resonant laser beam. Highly directional scattering of light and atoms was observed. This collective light scattering is shown to be directly analogous to Dicke superradiance, where the electronic coherence is replaced by the coherent center-of-mass motion of the atoms in the condensate. Superradiant Rayleigh scattering was used to amplify atomic matter waves. The active medium was a Bose-Einstein condensate, pumped by off-resonant laser light ("Dressed condensate"). An atomic wave packet was amplified with a gain of 10 to 100. Phase-coherence of the amplifier was verified by observing the interference of the output wave with a reference wave packet. Optical properties of the dressed condensate were also characterized, focusing on the key role of long-lived matter wave gratings produced by interference between the condensate at rest and the recoiling atoms. The narrow bandwidth for the optical gain gave rise to an extremely slow group velocity of an amplified light pulse ([approx.] 1 m/s).

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Physics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2001

Author dc:creator

• Inouye, Shin, 1971-

Advisor dc:contributor.advisor

• Wolfgang Ketterle.

• Physics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/8274

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/8274