Consider a Λ atom in a circularly polarized electromagnetic wave,there is a coherent superposition of its two lower states such that when the atom is initially in this superposed state,the atom will generate coherent trapping phenomenon.

Based on the model of the Λ-type three-level atomic system,the coherent population trapping(CPT) phenomenon is analyzed by semi-classical density matrix approach.

Based on the model of the Λ-type three-level atomic system,the impact of laser parameters on the CPT signals of rubidium atomic clock is analyzed by using the semi-classical density matrices approach in order to make a concrete analysis of the influence of laser parameters upon the stability performance of the CPT(coherent population trapping)atomic clock,and the comparison is presented.

We present the locking laser frequency on a Doppler absorption peak for the small size coherent population trapping (CPT) atomic frequency standard by using digital control circuit with a field-programmable gate array (FPGA) core.

We present theoretical analysis and experimental results of coherent population trapping within Zeeman sublevels of rubidium under Hanle configuration, and bichromatic dark states are firstly observed in the experiment.

Presently,the technique schemes for CPT clock include the traditional programme,adopting micro-electro-mechanical system(MEMS)technique for physical package,and adopting MEMS techn.