Chip-scale molecule trapping by a blue-detuned metasurface hollow beam

We propose a tightly focused hollow beam to trap cold molecules by using a metasurface grating, which has a hybrid phase with focusing and completely destructive interference functions. The intensity distributions of the hollow beam in free space concerning different structural parameters of the grating are theoretically studied in detail. The influences of both the discrete and continuous phases of the grating on the intensity distribution of the modulated optical field are compared. Our theoretical study shows that such a blue-detuned beam can provide a deep potential to trap cold molecules with a low photon scattering rate and a long trap lifetime. Our studies suggest that the metasurface-based optical chip is applicable to trap molecules and can be an ideal platform for building a robust quantum laboratory.