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Study of atom-surface interaction using magnetic atom mirror

Ashok Kumar Mohapatra

Dec 1, 20060 citations

Atomic reflection from a magnetic mirror: Beyond the adiabatic approximation

Uffe V. Poulsen, Klaus Mølmer

The European Physical Journal DJul 1, 20001 citation

Dynamics of cold atoms above a curved magnetic mirror

Edward A. Hinds, P. Bartoň, M. G. Boshier +2 more

APS April Meeting AbstractsApr 1, 19970 citations

Specular reflection of cold caesium atoms from a magnetostatic mirror

A. I. Sidorov, Russell McLean, W J Rowlands +5 more

We have observed specular reflection and multiple bounces of a beam of laser-cooled caesium atoms from a magnetostatic mirror consisting of an array of rare-earth permanent magnets. Using a time-of-flight absorption technique, the reflection coefficient of the mirror for caesium atoms pumped toward the m=+4 state is determined to be . For a beam of unpolarized atoms the reflectivity is found to be unexpectedly high, , which is attributed to contributions from atoms in m = 0, -1, -2 states which are reflected at high magnetic fields close to the surface of the mirror as a result of the quadratic Zeeman effect.We have observed specular reflection and multiple bounces of a beam of laser-cooled caesium atoms from a magnetostatic mirror consisting of an array of rare-earth permanent magnets. Using a time-of-flight absorption technique, the reflection coefficient of the mirror for caesium atoms pumped toward the m=+4 state is determined to be . For a beam of unpolarized atoms the reflectivity is found to be unexpectedly high, , which is attributed to contributions from atoms in m = 0, -1, -2 states which are reflected at high magnetic fields close to the surface of the mirror as a result of the quadratic Zeeman effect.

Quantum and Semiclassical Optics Journal of the European Optical Society Part BJun 1, 199682 citations

Atom optics with magnetic surfaces: II. Microscopic analysis of the `floppy disk' mirror

Ifan G. Hughes, P A Barton, Timothy Roach +1 more

In a recent experiment we studied cold rubidium atoms bouncing on a magnetic mirror made from a flexible computer disk with sinusoidal magnetization. The motion was well described by a model in which the mirror was a perfect specular reflector, but complete agreement with the data required the reflecting surface to be slightly corrugated. Here we explore the physical origins of the corrugation both theoretically and experimentally. First, we develop a theory relating the reflecting force on the atoms to the magnetization of the mirror, taking into account the finite thickness of the magnetic film. We find that if the signal on the floppy disk is not harmonic the atoms appear to have been reflected from a corrugated surface, as observed in our recent experiment. Next, we describe magnetic force microscope measurements which allow us to determine the distortion on the disk and hence to quantify its effect on the reflected atoms. We show that recording nonlinearity is indeed a major cause of the mirror roughness. We also consider other sources of roughness and identify an important effect associated with the boundaries between recorded tracks. Agreement between our experiment and theory suggests that we have identified the limiting factors in a real atom-optical element made from a floppy disk. At present the angular resolution of the mirror is approximately 35 mrad for atoms dropped from a height of 4 cm. We discuss how this can be improved to reach a level of 5 mrad or better.In a recent experiment we studied cold rubidium atoms bouncing on a magnetic mirror made from a flexible computer disk with sinusoidal magnetization. The motion was well described by a model in which the mirror was a perfect specular reflector, but complete agreement with the data required the reflecting surface to be slightly corrugated. Here we explore the physical origins of the corrugation both theoretically and experimentally. First, we develop a theory relating the reflecting force on the atoms to the magnetization of the mirror, taking into account the finite thickness of the magnetic film. We find that if the signal on the floppy disk is not harmonic the atoms appear to have been reflected from a corrugated surface, as observed in our recent experiment. Next, we describe magnetic force microscope measurements which allow us to determine the distortion on the disk and hence to quantify its effect on the reflected atoms. We show that recording nonlinearity is indeed a major cause of the mirror roughness. We also consider other sources of roughness and identify an important effect associated with the boundaries between recorded tracks. Agreement between our experiment and theory suggests that we have identified the limiting factors in a real atom-optical element made from a floppy disk. At present the angular resolution of the mirror is approximately 35 mrad for atoms dropped from a height of 4 cm. We discuss how this can be improved to reach a level of 5 mrad or better.

Journal of Physics B Atomic Molecular and Optical PhysicsMay 14, 199746 citations

Specular reflection of ultracold atoms from microfabricated magnetic mirrors

A. I. Sidorov, McLean, Russell J., David S. Gough +5 more

We report on the observation of highquality reflection of ultracold atoms from grooved perpendicular magnetic media with micronscale periodicities. The novel magnetic mirrors provide a very strong reflection with a small diffusive component that is introduced by the roughness of the reflecting potential. During reflection the atomic cloud obtains an rms angular spread of (8 + 10) mrad that corresponds to 3 photon recoils.

Jan 1, 20000 citations

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