Tight focusing of an atomic beam by the near field of diffracted laser light

V. I. Balykin, Vladimir G. Minogin

We analyze focusing of atomic beams by the atom near-field microlenses produced by the laser fields diffracted on the apertures in the metallic screens. Analysis of the focusing properties of the atom microlenses is given in a model describing dipole interaction of atoms with a far-off-resonance laser light. Two types of the atom microlenses are considered: The Bethe-type microlens with aperture less than the light wavelength and the Fresnel-type microlens with aperture about the wavelength. It is shown that both types of the atom microlenses are able to produce strong dipole gradient forces which can focus the atomic beams. However, while the Bethe-atom microlens is able to produce sharp focusing of the beams the Fresnel-atom microlens possesses weak focusing property due to high anharmonicity of the gradient force. We conclude that the Bethe-atom microlens can be considered as a promising tool of the atom optics potentially able to focus atomic beams into spot sizes about nanometers.

V. I. Balykin, Vladilen S Letokhov

В. В. Климов, Vladilen S Letokhov

This paper examines the focusing of an atomic beam by the near field of laser radiation diffracted by a small aperture. The wave properties of the atom are taken into consideration within the framework of an approximate Schrödinger equation. The possibility is demonstrated of focusing an atomic beam into a spot some 3 nm across, the atomic and laser beam characteristics being quite acceptable. The main contribution to the spot size is shown to be from spherical aberrations and diffraction effects, the chromatic aberrations of the atomic beam with a 5% velocity distribution broadening having a lesser effect.

В. В. Климов, Vladilen S Letokhov

Luke Maguire, Tracy R. Mackin, Karl Weber +2 more

Glen D. Gillen, Katharina Gillen, Shekhar Guha

In this chapter we present an interesting application of the propagation of laser light through linear optical media: the ability to spatially confine (trap) cold atoms within localized light intensity patterns. We first present some of the fundamentals for understanding how light can trap an atom. Depending upon the relationship between the properties of the atom and the properties of the laser light, atoms can be trapped in either localized dark spots, or localized bright spots. We will describe several light patterns for trapping atoms: The tightly localized bright and dark regions in the near-field diffraction patterns presented in Chapters 7 and 8 , The near-field patterns projected to a location far away from the diffracting aperture, and Polarization-dependent movable light field traps based on the near-field diffraction patterns.