High diffraction efficiency grating atom chip for magneto-optical trap

Magneto-optical traps based on grating chips can simplify cold atom physical package architectures significantly. Here we report the design and fabrication of a high-diffraction-efficiency grating magneto-optical trap (GMOT). The numerical simulation is performed with an optimized profile and measured refractive index of the gold film. In the design, the fabrication tolerance is also considered. The fabricated grating chip achieved a diffraction efficiency of up to 40%. Up to 2.8 × 107 are trapped with the chip, and the characterization of the GMOT is performed. High absorption contrast CPT resonance signal was also obtained. The proposed atom chip can be leveraged to realize compact cold atom clocks and other cold atom-based quantum sensors.