Dynamics of cold atoms above a curved magnetic mirror

Alice Quan, Daniel B. Erenso, Reeta Vyas

Uffe V. Poulsen, Klaus Mølmer

Ifan G. Hughes, P. A. Barton, M. G. Boshier +1 more

Multiple bounces of cold rubidium atoms have been observed for times up to one second in a trap formed by gravity and a 2 cm-diameter spherical mirror made from a sinusoidally magnetized floppy disk. We have studied the dynamics of the atoms bouncing in this trap from several different heights up to 40.5 mm and we conclude that the atoms are reflected specularly and with reflectivity 1.01(3). Slight roughness of the mirror is caused by harmonics in the magnetization of the surface and by discontinuities at the boundaries between recorded tracks. As the next step in this atom optics program we propose using a magnetic mirror to create a 2D atomic gas. We discuss how cold atoms can be loaded into the ground state of a static magnetic potential well that exists above the surface of the mirror as a consequence of the intermediate-field Zeeman effect.

Alexandra Bakman, Shmuel Fishman

Ifan G. Hughes, P A Barton, Timothy Roach +2 more

We have demonstrated that a suitably magnetized surface can be used to retroreflect cold atoms for applications in atom optics. This has some advantages relative to evanescent wave mirrors because no light is involved. Multiple bounces of cold rubidium atoms have been observed for times up to 1 s in a trap formed by gravity and a 2 cm diameter spherical mirror made from a flexible computer disk (`floppy disk'). We have studied the dynamics of the atoms bouncing in this trap from several different heights up to 40.5 mm and we conclude that the atoms are reflected specularly and with reflectivity 1.01(3). The performance of this mirror is limited at present by collisions with the background gas and by unwanted harmonics in the magnetization of the surface. This is the first in a series of papers concerning the use of magnetized surfaces in atom optics.

H. Merimeche

Reflective atom optics has been experimentally realized with a continuous flux of cold atoms by using a magnetized videotape. We have studied the behaviour of a slow atomic beam with a velocity of 20 m s(-1) incident at different angles on the surface of a curved magnetic mirror. Focusing of the beam has been demonstrated and this induces an amplification up to a factor 3 of the fluorescence emitted by the atoms around the focal point. We deduced the shape of our reflector from the focal length measurements and show that the result is completely consistent with those obtained from the reflection of a red diode laser beam on the curved mirror.