Efficient beam flattening for planar-integrated magneto-optical traps

The planar-integrated magneto-optical trap (PIMOT) offers a promising platform for miniaturizing cold atom systems, but its performance and laser-power efficiency are limited by the typically Gaussian profile of the input laser beam. In this work, we present a simplified and cost-effective beam shaping solution to transform the Gaussian input into a flat-top intensity distribution using a compact system of four spherical lenses. The reshaped light field could potentially enhances PIMOT performance by improving the uniformity of the optical radiation pressure and increasing the trap distance from the chip surface. With this approach, we demonstrate a substantial reduction in the optical power required to trap 2.5 × 10^{5 87}Rb atoms, down to 30% compared to a standard Gaussian beam input. Our results open the door to more efficient and flexible PIMOT systems for quantum sensing, metrology, and atom-based quantum technology.