High-contrast dark resonances with linearly polarized light on the D_(1) line of alkali atoms with large nuclear spin

摘要

High-contrast coherent population trapping signals were observed on the Cs D_(1) line by use of a bichromatic linear polarized light (lin||lin field). A maximum absorption contrast of about 10percent was obtained. This was nearly twice as high as that measured with the standard configuration of bichromatic circularly polarized light (sigma - sigma field). The results are compared with density matrix calculations of 4 and 5 level systems.