Effective working regions of the grating chip for planar-integrated magneto-optics trap

We experimentally investigate the effective working regions of a planar-integrated magneto-optical trap (MOT). By scanning a blocking point in the incident laser beam, we identify four effective working regions of the laser beam contributing to MOT: a central region corresponding to the downward incident beam and three regions associated with the upward diffracted beams. The latter three regions are the effective regions of the grating chip. It is demonstrated that only three 3.5 mm radius grating regions can produce a MOT that is capable of trapping 10⁵ atoms with a temperature below 150 μK, retaining over 60% of atoms compared to a complete grating chip. This finding suggests that more than 60% of the grating chip area can be saved for other on-chip components, such as metasurfaces and nanophotonic devices, without significantly compromising MOT performance, paving the way for more compact and versatile atom–photon interfaces.