IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Magnetic Interfaces and Nanostructures Tuesday Sessions
       Session MI-TuP

Paper MI-TuP9
Magnetic Circuits for Atomic Matter Waves

Tuesday, October 30, 2001, 5:30 pm, Room 134/135

Session: Emerging Materials & Nanostructures Poster Session
Presenter: M. Vengalattore, Harvard University
Authors: M. Vengalattore, Harvard University
W. Rooijakkers, Harvard University
S.A. Lee, Colorado State University
T. Deng, Harvard University
G.M. Whitesides, Harvard University
M. Prentiss, Harvard University
Correspondent: Click to Email
Atom optics is an important branch of physics in which the quantum nature of atoms is exploited to realize systems equivalent to photonics. An example is the (single mode) atomic waveguide as compared to the (single mode) optical fiber. Another example is the atom laser, based on matter wave amplification, realized in 1997.@footnote 1@ The production of these matter waves, which are coherent over distances > 10 cm has facilitated applications such as interferometry. Since atoms have a much larger mass than electrons or photons, they offer the unique possibility of doing ultrasensitive gravitational field measurements. Furthermore, since the interactions can be controlled, neutral cold atoms provide a promising system for quantum computation. Following the integration in optics and electronics it makes sense to pursue miniaturization of atom-optical systems. This will allow for the realization of more complex functions on a relatively small surface. Arguably magnetic field gradients provide the most versatile means for non-dissipative manipulation of atoms. In this paper we describe a newly developed waveguide for coherent transport of atoms and possible future applications of this technology. Our waveguide consists of four parallel strips of ferromagnetic material, wound with kapton isolated wire. This configuration results in a magnetic field minimum above the surface. The position of this minimum can be controlled by varying the currents in the wires. Weak field seeking atoms can be trapped in this minimum by using laser cooling techniques, forming a magneto optical trap (MOT).@footnote 2@ Atoms from the background vapor are decelerated by laser beams and accumulate in the magnetic minimum. To provide damping in all directions the surface above the magnetic strips has been made reflective with a gold layer. In our experiment we use diode lasers with a wavelength of 852 nm to cool @super 133@Cesium atoms. The fluorescence of the atoms can be imaged onto a CCD camera. We have created very long (aspect ratio 1:500) and thin (20 mm) clouds. In our waveguide we obtain a gradient of 3 kG cm@super -1@ A@super -1@, and by further miniaturization we anticipate a further increase by a factor 10@super 3@. The next step is fabricating more complex structures. One example is the quantum point contact: a constriction through which the conductance of matter waves shows steps as a consequence of the quantum mechanics.@footnote 3@ Another example is a magnetic storage ring for atoms. Connecting up both ends of our waveguide seems a logical extension of our previous work. We are pursuing the propagation of matter waves in such a device, which may then be used as an interferometer for ultrasensitive inertial sensing. Presently we use mu-metal sheet to construct these devices. Alternatively we have also been using lithography@footnote 4@ and permalloy deposition. We continue our search for materials capable of generating large magnetic field gradients on a small substrate with the possibility of designing complex circuits for ultracold atoms. @FootnoteText@@footnote 1@M. Andrews, C. Townsend, H-J Miesner, D. Durfee, D. Kurn and W. Ketterle, Science 275, 637 (1997). @footnote 2@E. Raab, M. Prentiss, A. Cable, S. Chu and D.E. Pritchard, Phys. Rev. Lett. 48, 596 (1982). @footnote 3@J. H. Thywissen, R.M. Westervelt and M. Prentiss, Phys. Rev. Lett. 83, 3762 (1999). @footnote 4@N. H. Dekker, C. S. Lee, V. Lorent, J. H. Thywissen, S. P. Smith, M. Drndic, R. M. Westervelt and M. Prentiss, Phys. Rev. Lett. 84, 1124 (2000).