Ultracold atoms in optical resonators
Schematic plot of a Bose-Einstein condensate (BEC) interacting with a single mode optical cavity. The cavity mode is described by a cos(kx) function along the cavity axis while it has a Gaussian envelope in the transverse direction. The BEC wave function evolves dynamically in time due to the interaction with the radiation field. The figure illustrates self-organization. A quasi homogeneous BEC (which has a shape of an elongated ellipsoid with its semi major axis well exceeding the optical wavelength) is illuminated by a pumping laser perpendicular to the cavity axis. When the intensity of the pump laser is below a threshold value (left panel) the BEC wave function remains homogeneous and incapable of scattering a classical field into the resonator. However, above threshold intensity (right panel) the BEC self-organizes into a one-wavelength pattern that scatters photons constructively into the resonator and thus stabilizes the optical potential supporting the Bragg lattice.