Atomic Guide With A Hollow Metallic Waveguide And Its Generation Of Hollow Laser Beam

The methods for laser and magnet guiding of neutral atoms include red-detuned laser guiding, blued-detuned laser guiding, current-carry lead guiding, current-carry conductor guiding and permanent magnet atomic guiding are briefly introduced in this paper, we also introduced the definition of atomic funnel and its basic principle and generation, finally, the potential applications of atomic funnel in atom optics are discussed.We proposed a new scheme to guide cold atoms using a blue-detuned TE01doughnut mode in a hollow metallic waveguide(¹0microns),it involved the advantages of both blue-detuned laser atomic guiding hollow fiber atomic guiding. We calculated the electromagnetic field distribution of the guiding modes in the hollow metallic waveguide, discussed the mode attenuation characteristic in waveguides of different media and radius, and find the method to restrain other modes' propagation: mode matching and choosing the right media to increase the EH11 mode's attenuation. For the TE01 mode which is represented by the fist kind Bessel function, we calculated its optic intensity distribution, then calculated the relationship between its optical potential for the two-level 85Rb atoms and the detuning, and estimate its photon scattering rate. We find that the optical potential(U_max = 570mK ) of the TE01 mode is high enough to load cold atoms (-120 μK)from a standard magneto-optical trap and guide them in the HMW, and the photon scattering rate is so low that can be neglect. It proved that our scheme is desirable to realize a computer-controlled atom lithography with an arbitrary pattern.Diffracted near- and far-field distributions of the TE₀₁-mode output beam under the Fresnel approximation are studies. We find the output beam is a dark hollow one which can be analyzed by the pattern of a TEM₀₁* donut mode. When we pay attention to the near-field, we find that the beam will be focused by itself in a short propagation distance, for a 20-micron-radius hollow waveguide, the focus will appears when it propagate about 300 microns, and the DSS will decrease from 10.5 microns to 6.2 microns. We changed the radius and obtained a similar result. Finally,we discussed the TE01 output beam's potential applications in atom optics, such as atomic funnel and guiding or atomic lens, and calculated the corresponding potential and optimal detuning...