ZEEMAN-COHERENCE-INDUCED TRANSPARENCY AND GAIN WITHOUT INVERSION IN LASER-COOLED RUBIDIUM

We report experiments demonstrating the effects of optical pumping, co herent population trapping and light polarisation on electromagnetical ly induced transparency in simple h-type configurations of rubidium 87 where the relevant coherences are within the three Zeeman substates o f the F = 1 component of the 5S(1/2) ground level. Inversionless gain is also demonstrated. The sample is cooled to below 1 mK in a magneto- optic trap operating without repumping light to give a working populat ion of F = 1 ground state atoms. The experimental results are compared with master equation computations of a closed seven-substate-model re presenting the ground level (F = 1) and the excited levels F' = 0 and F' = 1. (C) 1998 Elsevier Science B.V. All rights reserved.