Atom optics with an adaptable magnetic reflector

Advances in laser cooling techniques have made it possible to prepare atomic samples with temperatures of a few micro-Kelvin or less. This stimulated the field of atom optics in which, in analogy to conventional light optics, atom clouds or single atoms are trapped, guided, reflected and diffracted. Magnetic reflectors have been fabricated from a number of materials, including magnetic information storage media. In this thesis we describe experiments manipulating a cold atom cloud by a curved magnetic reflector, fabricated from commercial videotape, in combination with external magnetic fields. The concave spherical shape gives rise to focussing and collimation of the reflected atom cloud. A cloud of typically 10"7 "8"5Rb atoms with a temperature of about 16 #mu#K is prepared in a magneto-optical trap and optical molasses. The cloud is released from a height of 27 mm, reflected off the horizontal magnetic reflector and refocused at its initial position. We utilize the refocused atom cloud to probe corrugations in the reflecting potential introduced by the addition of external magnetic fields. We investigate the atomic motion theoretically and experimentally under application of static, oscillating and rotating external magnetic fields. A static external field leads to splitting of the atom cloud at the position where it usually refocuses. The splitting can be controlled by the magnitude of the external field. For an oscillating external field the shape of the atom cloud is also governed by the oscillation frequency. Rotating external fields give rise to a reflecting potential with moving corrugations. Momentum is transferred to the atom cloud through ''surfing'' on the corrugations. This last experiment is an early demonstration of atom transport using magnetic potentials. The experiments described in this thesis demonstrate that although the magnetic reflector has permanent magnetisation, the combination with an external magnetic field provides an adaptable atom optics element. (author)SIGLEAvailable from British Library Document Supply Centre-DSC:DXN041848 / BLDSC - British Library Document Supply CentreGBUnited Kingdo