Phase dependent Coherent Population Trapping

Wolfgang Maichen, Rainer Gaggl, Ferruccio Renzoni +4 more

Wolfgang Maichen, Rainer Gaggl, Eugeny Korsunsky +1 more

Yandong Peng, Xiangming Hu, Gong Cheng

We present the phase control of photon correlations in a driven four-level system in the double lambda configuration. The strong correlation and the anticorrelation are obtained when the collective phase of four applied laser fields is varied. The coherent control is based on the phase-dependent coherent population trapping (CPT). The strong correlation occurs when the system operates near CPT, while the anticorrelation occurs when the system is far away from CPT.

Wolfgang Maichen, Richard Gaggl, Eugeny Korsunsky +1 more

Phase-dependent coherent population trapping (CPT) was observed using a thermal Na atomic beam irradiated by four laser fields derived from two dye lasers. Investigations were made on Λ- and double Λ-systems created in the D 1 line, both with and without magnetic field that lifts degeneracy of the Zeeman sublevels. In all cases a sharp decrease of fluorescence intensity was observed for certain values of the relative phase of the light waves, indicating that the occurrence of CPT depends on this phase. The shape of the phase dependence as well as its behaviour with respect to laser intensity fits well theoretical predictions.

William R. Kelly, Zachary Dutton, J. Schlafer +4 more

The phenomenon of coherent population trapping (CPT) of an atom (or solid state "artificial atom"), and the associated effect of electromagnetically induced transparency (EIT), are clear demonstrations of quantum interference due to coherence in multilevel quantum systems. We report observation of CPT in a superconducting phase qubit by simultaneously driving two coherent transitions in a Lambda-type configuration, utilizing the three lowest lying levels of a local minimum of a phase qubit. We observe 60(+/-7)% suppression of the excited state population under conditions of CPT resonance. We present data and matching theoretical simulations showing the development of CPT in time. Finally, we used the observed time dependence of the excited state population to characterize quantum dephasing times of the system.

Thomas Lindvall, Mikko Merimaa, Ilkka Juhani Tittonen