High resolution spectroscopy of Cs vapor confined in optical cells of few-micron thicknesses

Abstract

We present here the new behavior of Electromagnetically Induced Transparency (EIT), Velocity Selective Optical Pumping (VSOP) and Velocity Selective Excitation (VSE) resonances observed in Cs vapor confined in unique cells with thicknesses L = 1.5λ and L = 6λ. It is shown experimentally that in both cells, the EIT resonance is significantly narrower than would be expected from the ground state dephasing rate due to atomic collisions with the cell windows. The enhanced absorption (fluorescence) narrow VSOP resonance at the closed transition transforms into reduced absorption (fluorescence) one with small increase of atomic concentration or light intensity. A striking difference appears between the VSE resonance broadening due to excited atom thermalization, in L = 6λ and conventional L = 2.5 cm cells.