Istituto Nazionale di Ottica

Università di Pisa

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Optical lattice - Setup

Bose-Einstein condensate in optical lattices: experimental setup

The experimental setup described in detail in [1,2]. Briefly, we create condensates of N ~ 104 rubidium atoms in a time-orbiting potential trap. Once condensation has been achieved, the mean trapping frequency trap of the magnetic trap is adiabatically reduced to values between 15 and 50 Hz. Thereafter, two laser beams with waists of 1.8 mm and intersecting at an angle 180 (38) degrees at the position of the condensate are switched on with a linear ramp of duration 10 ms, thus ensuring adiabaticity of the loading process. The beams are detuned to the red side of the rubidium atomic resonance by ~ 30 GHz and have a variable frequency difference between them, controllable through two acousto-optic modulators which are also used to vary the intensity of the beams. In this way, a periodic potential with lattice constant d = 0.39 (1.18) µm and lattice recoil energy Erec / h = 3770 (455) Hz is created, which through the frequency difference Δν can be made to move at a constant velocity v = d Δν or accelerated with aL = d dΔν/dt .
  1. O. Morsch et al.
    Phys. Rev. Lett. 87, 140402 (2001).
  2. M. Cristiani et al.
    Phys. Rev. A 65, 063612 (2002).

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