Anisotropic velocity distributions in 3D optical lattices

Summary form only given. We have measured velocity distributions in two dimensions, as a function of intensity, in a 3D near resonant optical lattice (NROL) in Cs. The NROL is created by two orthogonally polarized pairs of laser beams that propagate in the yz and xz plane respectively. The angle between the beams of each pair is 90/spl deg/ and each beam forms an angle of /spl theta/=45/spl deg/ with the (vertical) quantization (z-) axis. This results in a tetragonal structure in which the lattice constants are a/sub z/=/spl lambda//(2/spl radic/2) and a/sub x,y/=/spl lambda//2, where /spl lambda/=852 nm. The difference in lattice constants means that lattice sites have anisotropy trapping potentials, where the oscillation frequencies differ with a factor of 2 along x and z, in a harmonic approximation.