ELECTRON SHELVING INDUCED SQUEEZING IN FLUORESCENT LIGHT EMITTED BY COLD 4He ATOMS IN AN OPTICAL LATTICE: COHERENT CONTROL BY A WEAK AXIAL MAGNETIC FIELD

Abstract

We report theoretical calculations on the effect of polarization gradient, atomic motion and an axial magnetic field on quantum noise reduction in the resonant fluorescence emitted by a cloud of cold Helium atoms in an optical lattice. The polarization gradient induces squeezing of the electromagnetic field at selected points on the optical lattice, together with a dark resonance in the emitted fluorescence, the origin of which is traced back to electron shelving. We find that the localization of the atoms in the optical lattice destroys squeezing, but can be recovered in the presence of an axial magnetic field.