SELF-TRAPPING AND SELF-FOCUSING OF A COHERENT ATOMIC-BEAM

Light-induced dipole-dipole interaction in a coherent atomic-field res ults in an effective nonlinearity for atoms. This nonlinearity can ind uce self-trapping and self-focusing of a coherent atomic beam undergoi ng propagation through a traveling-wave laser beam. we show how such a scheme could be realized and evaluate the critical density required f or atomic self-trapping and self-focusing. An analogy to optical self- trapping and self-focusing is discussed.