Trapping of cold atoms for the hybrid system near a circular aperture with subwavelength size

We propose and analyze a scheme to generate an optical trap for cold atoms using a thin circular aperture with a radius similar to or smaller than the wavelength diffracted by a plane light in the near field. The diffracted intensity in the near field is investigated by the vector theory as well as the optical potential and van der Waals potential for 87Rb atoms are calculated in the trap. It shows that the total potential can form an attracting 3D localized trap for cold atoms with red-detuned light near the thin circular aperture below the diffraction limit. It shows that the spontaneous-emitting rate, Rayleigh and Raman scattering rates of trapped cold atoms are very small for the CO2 laser. This scheme can provide an opportunity towards the generation of the hybrid system consisting of isolated atoms and solid devices.