Anti-relaxation coating-induced velocity-dependent population re-distribution in electromagnetically induced transparency

Abstract

In an uncoated vapor cell, transmission spectra obtained for electromagnetically induced transparency (EIT) for D2 line of 87 Rb shows asymmetry and (or) absorption in the presence of magnetic field. In this study, complete conversion from asymmetry/absorption to transmission is found by using octadecyltrichlorosilane (OTS) as an anti-relaxation coating. The experimental results were interpreted as velocity dependent population alignment in the ground states induced by the coating which results in the conversion from absorption to transmission. A simple theoretical model based on density matrix is presented for qualitative interpretation of the results.