High-brightness atom source for atomic fountains

We launch Cs atoms using a moving three-dimensional (3D) optical lattice. Atoms are initially spin polarized and cooled to the ground state of the optical potential using 3D Raman sideband cooling and then accelerated in the lattice to velocities of up to $3\hspace{0.5em}\mathrm{m}/\mathrm{s}.$ Subsequent adiabatic lowering of the potential releases the atoms from the lattice. Three-dimensional kinetic temperatures as low as $200\hspace{0.5em}\mathrm{nK}$ were achieved. The observed temperature of the launch is independent of the acceleration and final velocity of the atoms. In an alternative approach, we first accelerate the atoms to velocities of up to 5 m/s using moving molasses and then cool them with the lattice in the comoving frame of the atoms to temperatures as low as 150 nK.