Transport of laser emission with broadband spectrum in optically dense atomic medium under the coherent population trapping

The paper presents a theory describing the formation of the coherent population trapping resonance for the finite laser bandwidth in an optically-dense medium of atoms inside a buffer gas cell. The equations of the atomic density matrix are established, as well as the transfer equations of laser emission spectrum inside a cell with working and buffer gas at a determined temperature. The dependence of the quality of the coherent population trapping resonance on the laser bandwidth has been studied in the case of detecting the signal of the transmitted emission and the fluorescence signal.