PULSED POLARIZATION GRADIENT COOLING IN AN OPTICAL DIPOLE TRAP WITH ALAGUERRE-GAUSSIAN LASER-BEAM

We utilized a blue-detuned Laguerre-Gaussian (doughnut) laser beam to trap cold rubidium atoms by optical dipole force. ''Pulsed'' polarisat ion gradient cooling was applied to the trapped atoms to suppress the trap loss due to heating caused by random photon scattering of the tra pping light. In this trap about 10(8) atoms were initially captured an d the trap lifetime was 1.5 s, which was consistent with losses due to background gas collisions. This trap can readily be applied to atom g uiding, compression, and evaporative cooling.