Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Europhysics Letters (EPL)

Observation of Phase-Dependent Coherent Population Trapping in Optically Closed Atomic Systems

Wolfgang Maichen, Richard Gaggl, Eugeny Korsunsky, Laurentius Windholz

Published Aug 1, 1995• 43 citations
Publisher

Abstract

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.

DOI
10.1209/0295-5075/31/4/001

Related papers

Coherent population trapping in a Λ configuration coupled by magnetic dipole interactions

Huidong Kim, Hyok Sang Han, Tai Hyun Yoon +1 more

We report our study on coherent population trapping (CPT) in a $\ensuremath{\Lambda}$ configuration coupled by magnetic dipole interactions. The $\ensuremath{\Lambda}$ configuration is formed by bichromatic radio-frequency fields coupling a pair of Zeeman sublevels in one hyperfine level of an alkali-metal atom to another sublevel in the other hyperfine level. The Zeeman sublevel at the apex is coupled to a state in the $nP$ manifold via an optical transition on one of the spectroscopic $D$ lines to induce optical pumping to a dark state. The configuration is closed without leakage to other Zeeman sublevels. We use lithium atoms in an optical trap for our experimental study. The system allows independent control of the main parameters characterizing CPT, which include the upper-state decay rate and the decoherence rate as well as the Rabi frequencies. By turning off the applied fields, the system is frozen so that its quantum state can be measured precisely. We studied the line shapes and dynamics of the CPT system, and measured the phase relation of the dark superposition state to find excellent agreement with theory. The possible application of the scheme as a method to cool optically trapped atoms below the recoil limit in a manner analogous to velocity-selective coherent population trapping is discussed.

Physical Review A•Mar 10, 2014•7 citations

Transient coherent population trapping in a closed loop interaction scheme

Wolfgang Maichen, Ferruccio Renzoni, I. E. Mazets +2 more

We investigated the existence of coherent population trapping (CPT) as a transient effect dependent on the rate of change of interaction parameters between an atom and light waves. For that purpose we exploited the phase dependence of CPT in a closed double-\ensuremath{\Lambda} interaction scheme, varying the total phase of the atomic transition loop linearly in time by detuning the light waves from exact four-photon resonance. For a slowly changing phase (that is, for small detunings) we observed the subsequent creation and destruction of CPT depending on the varying phase, while for higher speed of phase change CPT disappears. An analytical solution for a special case for a double-\ensuremath{\Lambda} interaction scheme that can be used to understand the principles of this phenomenon is presented. A qualitative comparison with our experiment shows good agreement within the limits of our theoretical considerations, confirming the validity of the basic idea. \textcopyright{} 1996 The American Physical Society.

Physical Review A•May 1, 1996•54 citations

Observation of coherent population trapping in a V-type two-electron system

Alok K. Singh, Vasant Natarajan A

We observe coherent population trapping (CPT) in a two-electron atom— 174 Yb—using the transition. CPT is not possible for such a transition according to one-electron theory because the magnetic sublevels form a V-type system, but in a two-electron atom like Yb, the interaction of the electrons transforms the level structure into a Λ -type system, which allows the formation of a dark state and hence the observation of CPT. Since the two levels involved are degenerate, we use a magnetic field to lift the degeneracy. The single fluorescence dip then splits into five dips—the central unshifted one corresponds to coherent population oscillation, while the outer four are due to CPT. The linewidth of the CPT resonance is about 300 kHz and is limited by the natural linewidth of the excited state, which is to be expected because the excited state is involved in the formation of the dark state.

arXiv:1502.03079•New Journal of Physics•Mar 31, 2015•4 citations

Coherent Population Trapping in Multi-Level Atomic Systems

Laurentius Windholz

Coherent population trapping (CPT) is treated in multi–level systems, excited by two– or four–frequency laser light. The dynamics of filling non–absorbing (dark) states is investigated. In cases where all transitions involved are excited (closed systems), the effect becomes dependent on the relative phase of the light waves. Further electromagnetically induced transparency (EIT) is described in three– and four–level systems and used for effective side band generation.

Physica Scripta•Jan 1, 2001•13 citations

The pecularities of coherent population trapping resonances on fine structure levels for different light polarization

T. Ya. Karagodova, Alexander I. Karagodov

At the conditions of two-photon resonance the effect of coherent population trapping (CPT) can take place. The CPT may be observed as in absorption so in resonance fluorescence. The CPT is widely applied in high resolution spectroscopy, laser cooling, atomic optics and so on. Earlier the peculiarities of CPT resonances on fine structure levels of an atom have been considered on example of thallium atoms. It was shown that the form and number of resonances are influenced by geometry of experiment and initial conditions (initial level populations). As the investigations of CPT on fine structure levels are the object of interest last years, we have considered the numerical analysis of dependence the form of CPT resonances on fine structure levels of T1 atoms as lower levels of Λ-system on polarization of radiation fields. The cases of elliptical, linear and circular polarization have been considered.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Jul 11, 2006•0 citations

CPT effect and its applications for weak electromagnetic field detection

C. Andreeva, Yordanka V. Dancheva, G. Alzetta +2 more

Summary form only given. We have performed experimental investigations of the coherent population trapping (CPT) phenomenon at a single hyperfine transition at the D/sub 1/ and D/sub 2/ lines of Rb in a cell, inserted inside a magnetic shield. For observation of CPT dark resonances at a single hyperfine transition the Zeeman degeneracy has to be removed. This was achieved by applying a homogeneous magnetic field H/sub 1/, parallel to the laser beam and scanned in both directions around zero value. Additional coil produced constant magnetic or RF electromagnetic field H/sub 2/ perpendicular to the beam propagation. The fluorescence signal was registered in order to investigate the influence of the additional electromagnetic field on the dark line parameters. It was observed that the width and the contrast of the dark line are very sensitive to the applied field H/sub 2./ Increasing the value/amplitude of H/sub 2/ causes increase of the width and decrease of the contrast of the CPT resonances.

Trans Black Sea Region Symposium on Applied Electromagnetism•Nov 11, 2002•0 citations
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.
We report our study on coherent population trapping (CPT) in a $\ensuremath{\Lambda}$ configuration coupled by magnetic dipole interactions. The $\ensuremath{\Lambda}$ configuration is formed by bichromatic radio-frequency fields coupling a pair of Zeeman sublevels in one hyperfine level of an alkali-metal atom to another sublevel in the other hyperfine level. The Zeeman sublevel at the apex is coupled to a state in the nPnPnP manifold via an optical transition on one of the spectroscopic DDD lines to induce optical pumping to a dark state. The configuration is closed without leakage to other Zeeman sublevels. We use lithium atoms in an optical trap for our experimental study. The system allows independent control of the main parameters characterizing CPT, which include the upper-state decay rate and the decoherence rate as well as the Rabi frequencies. By turning off the applied fields, the system is frozen so that its quantum state can be measured precisely. We studied the line shapes and dynamics of the CPT system, and measured the phase relation of the dark superposition state to find excellent agreement with theory. The possible application of the scheme as a method to cool optically trapped atoms below the recoil limit in a manner analogous to velocity-selective coherent population trapping is discussed.
We investigated the existence of coherent population trapping (CPT) as a transient effect dependent on the rate of change of interaction parameters between an atom and light waves. For that purpose we exploited the phase dependence of CPT in a closed double-\ensuremath{\Lambda} interaction scheme, varying the total phase of the atomic transition loop linearly in time by detuning the light waves from exact four-photon resonance. For a slowly changing phase (that is, for small detunings) we observed the subsequent creation and destruction of CPT depending on the varying phase, while for higher speed of phase change CPT disappears. An analytical solution for a special case for a double-\ensuremath{\Lambda} interaction scheme that can be used to understand the principles of this phenomenon is presented. A qualitative comparison with our experiment shows good agreement within the limits of our theoretical considerations, confirming the validity of the basic idea. \textcopyright{} 1996 The American Physical Society.
We observe coherent population trapping (CPT) in a two-electron atom— 174 Yb—using the transition. CPT is not possible for such a transition according to one-electron theory because the magnetic sublevels form a V-type system, but in a two-electron atom like Yb, the interaction of the electrons transforms the level structure into a Λ -type system, which allows the formation of a dark state and hence the observation of CPT. Since the two levels involved are degenerate, we use a magnetic field to lift the degeneracy. The single fluorescence dip then splits into five dips—the central unshifted one corresponds to coherent population oscillation, while the outer four are due to CPT. The linewidth of the CPT resonance is about 300 kHz and is limited by the natural linewidth of the excited state, which is to be expected because the excited state is involved in the formation of the dark state.
At the conditions of two-photon resonance the effect of coherent population trapping (CPT) can take place. The CPT may be observed as in absorption so in resonance fluorescence. The CPT is widely applied in high resolution spectroscopy, laser cooling, atomic optics and so on. Earlier the peculiarities of CPT resonances on fine structure levels of an atom have been considered on example of thallium atoms. It was shown that the form and number of resonances are influenced by geometry of experiment and initial conditions (initial level populations). As the investigations of CPT on fine structure levels are the object of interest last years, we have considered the numerical analysis of dependence the form of CPT resonances on fine structure levels of T1 atoms as lower levels of Λ-system on polarization of radiation fields. The cases of elliptical, linear and circular polarization have been considered.
Summary form only given. We have performed experimental investigations of the coherent population trapping (CPT) phenomenon at a single hyperfine transition at the D/sub 1/ and D/sub 2/ lines of Rb in a cell, inserted inside a magnetic shield. For observation of CPT dark resonances at a single hyperfine transition the Zeeman degeneracy has to be removed. This was achieved by applying a homogeneous magnetic field H/sub 1/, parallel to the laser beam and scanned in both directions around zero value. Additional coil produced constant magnetic or RF electromagnetic field H/sub 2/ perpendicular to the beam propagation. The fluorescence signal was registered in order to investigate the influence of the additional electromagnetic field on the dark line parameters. It was observed that the width and the contrast of the dark line are very sensitive to the applied field H/sub 2./ Increasing the value/amplitude of H/sub 2/ causes increase of the width and decrease of the contrast of the CPT resonances.