On-chip Si3N4 grating outcoupler for magneto-optical trap in a cold atom system

Cold atoms play an important role in fundamental physics, precision timekeeping, quantum sensing, and quantum computing.The production of cold atoms requires magneto-optical traps (MOTs), but current MOTs consist of a variety of complex and bulky optical infrastructures that hamper their practical application.The development of integrated photonic circuits offers the opportunity to achieve integrated MOTs.Here, we take advantage of the ultra-low loss of the silicon nitride platform to design a grating outcoupler for coupling beams from waveguides to free space.The device operates at a wavelength of 780 nm with an experimental emission angle of 24.38.Additionally, by appropriately designing the positions of the grating outcouplers on the chip, we propose an on-chip emission system to demonstrate the MOT application.The intersection area is about 2 mm 2 mm at a height of 6 mm on the chip.Our work provides the possibility of realizing on-chip MOTs.