Abstract

A simple three-wire-based magnetic microtrap for direct forced evaporative cooling of neutral atoms without using induced spin-flip has been proposed1 . We introduce two simple permanent magnetic microstructures, for creating single 3D magnetic microtrap and direct forced evaporative cooling of neutral atoms without using spin-flip technolo- gies to attain Bose-Einstein condensation. In each configuration, a bias magnetic field, B1, is applied to vary the trap depth, frequencies and minimum of absolute value of the magnetic field, B. According to the Figure 1, for an L-shaped configuration of perma- nent magnets, when B1z changes from −10G to −7G the trap depth is reduced. As di- agrams show, xmin = 0 but ymin and zmin change with the bias field. Figure 2 shows a U-shaped configuration of permanent magnets. When B1z changes from zero to 5G the depth of the trap is decreased. The center of the microtrap remains at xmin = ymin = 0 and zmin = 5.28µm while B1z varies.