Diffraction patterns of laser light for use as optical dipole traps for cold atoms

Using Kirchhoff and Hertz vector diffraction theory we calculate detailed light distributions beyond a circular aperture. Within the diffraction pattern, localized bright and dark spots exist. If the trap laser is red-detuned atoms will be trapped in the localized light field maxima, while blue-detuned light results in atoms being trapped in light field minima. The primary advantages of using diffracted light fields to trap cold neutral atoms resides in the experimental simplicity of a single loosely focused laser beam incident upon a diffracting aperture and the ability to use either blue- or red-detuned laser light. Extension of this method to multi-dimensional arrays of apertures in a mask will result in multi-dimensional arrays of dipole atom traps. Calculations of the trap potential wells and experimental verification of the existence of the light field distributions will be presented.