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

Journal of Natural Science of Heilongjiang University

Probe gain based on atomic coherent effects in a four-level system

Yang Ting-hui

Published Jan 1, 2007• 0 citations
OpenAlex

Abstract

A four-level system driven by two coherent fields is considered. the probe gain at a short wavelength can be achieved due to the quantum interference in the presence of an incoherent pump. The density matrix calculation provides the conditions for probe amplification from different origin, including gain without population inversion in any state basis, gain with population inversion in the dressed-state basis, and gain with population inversion in the bare-state basis. Also, by controlling Rabi frequency of the coupling field a totally changing from non-inversion to inversion can be achieved which does not depend on the intensity of the incoherent pump.

Related papers

Quantum interference effects on the probe amplification without and with inversion in a four-level system

Bing Zhang, Weihua Xu, Zhang Hui-Fang +1 more

A four-level system driven by two coherent fields is considered. It is shown that in the presence of an incoherent pump, the probe gain at a short wavelength can be achieved due to the quantum interference. Our density matrix calculation provides the conditions for probe amplification from different origins, including gain without population inversion on any state basis, gain with population inversion on the dressed-state basis and gain with population inversion on the bare-state basis. Also, by controlling the Rabi frequency of the coupling field a total change from non-inversion to inversion can be achieved which does not depend on the intensity of the incoherent pump.

Chinese Physics•Sep 28, 2004•4 citations

The probe gain with and without inversion in a four-level atomic model: light amplification at a short wavelength

Wu Jin-Hui, Deng-Pan Wang, Zhang Hui-Fang +2 more

We propose a new four-level atomic model for achieving light amplification at a short wavelength, where direct incoherent pumping into the top level is avoided by the advantage of coherent pumping. In this model, the lower level of the probe transition is an excited state but not the usual ground state. By analytical as well as numerical calculations, we find that the probe gain, either with or without population inversion, which depends on the relation between spontaneous decay rates γ42 and γ21, can be achieved with proper parameters. We note that the Raman scattering gain always plays an important role in achieving the probe amplification.

Chinese Physics•Jan 1, 2003•5 citations

The probe gain with and without inversion in a four-level atomic model: light amplification at a short wavelength

吴金辉, 王登攀, 张惠芳 +2 more

We propose a new four-level atomic model for achieving light amplification at a short wavelength,where direct incoherent pumping into the top level is avoided by the advantage of coherent pumping.In this model,the lower level of the probe transition is an excited state but not the usual ground state.By analytical as well as numerical calculations,we find that the probe gain,either with or without population inversion,which depends on the relation between spontaneous decay rates γ42 and γ21,can be achieved with proper parameters.we note that the Raman Scattering gain always plays an important role in achieving the rpobe amplification.

中国物理B：英文版•Jan 20, 2003•0 citations

Role of incoherent pumping scheme on gain without population inversion in four-level systems

Bibhas Kumar Dutta, P.K. Mahapatra

We have studied gain without population inversion in two similar four-level systems by employing semiclassical density-matrix formalism. If the incoherent pumping process is not taken into account, both systems can be visualized as an ideal V-type system. Along with the application of strong pump and weak probe fields, an incoherent pump field is added to each of the systems in a different configuration. It has been shown that the different mechanisms of application of an incoherent pump to the system can appreciably change the population difference between the energy levels of the strongly driven transition and results in the evolution of inversionless gain either at the line center or at the sidebands on probe detuning. The effect of inhomogeneous broadening on the probe gain has also been studied.

Physica Scripta•Jan 23, 2008•14 citations

Amplification without Inversion in the Four-level N-Type 87Rb D1-Line

Han Seb Moon, Yong Soo Choe, Hyun Ah Kim +3 more

We demonstrate amplification without inversion in the 87Rb D1-line pumped by an incoherent light. A closed N-type, four-level atomic system has been considered to obtain an insight into the origin of the gain as well as the conditions under which the system exhibits gain without population inversion in bare states. We investigate the gain as a function of the incoherent pumping rate, the coupling laser detuning, and Rabi frequency. The experimental results are in good agreement with the numerical calculations considering the velocity distribution of atoms.

Japanese Journal of Applied Physics•Jan 1, 2000•10 citations

Probe gain with population inversion in a four-level atomic system with vacuum-induced coherence

Jin‐Hui Wu, Huifang Zhang, Jin-Yue Gao

For a four-level atomic system with a doublet of closely spaced levels, we find that, owing to the coherence that results from the vacuum of the radiation field, population trapping at excited levels and probe gain with population inversion can be achieved with weak incoherent pumping. This gain is different from both the conventional lasing gain and gain without inversion in that there exists population inversion on probe transitions but the inversion is achieved by the vacuum-induced coherence.

Optics Letters•Apr 15, 2003•34 citations
A four-level system driven by two coherent fields is considered. the probe gain at a short wavelength can be achieved due to the quantum interference in the presence of an incoherent pump. The density matrix calculation provides the conditions for probe amplification from different origin, including gain without population inversion in any state basis, gain with population inversion in the dressed-state basis, and gain with population inversion in the bare-state basis. Also, by controlling Rabi frequency of the coupling field a totally changing from non-inversion to inversion can be achieved which does not depend on the intensity of the incoherent pump.
A four-level system driven by two coherent fields is considered. It is shown that in the presence of an incoherent pump, the probe gain at a short wavelength can be achieved due to the quantum interference. Our density matrix calculation provides the conditions for probe amplification from different origins, including gain without population inversion on any state basis, gain with population inversion on the dressed-state basis and gain with population inversion on the bare-state basis. Also, by controlling the Rabi frequency of the coupling field a total change from non-inversion to inversion can be achieved which does not depend on the intensity of the incoherent pump.
We propose a new four-level atomic model for achieving light amplification at a short wavelength, where direct incoherent pumping into the top level is avoided by the advantage of coherent pumping. In this model, the lower level of the probe transition is an excited state but not the usual ground state. By analytical as well as numerical calculations, we find that the probe gain, either with or without population inversion, which depends on the relation between spontaneous decay rates γ42 and γ21, can be achieved with proper parameters. We note that the Raman scattering gain always plays an important role in achieving the probe amplification.
We propose a new four-level atomic model for achieving light amplification at a short wavelength,where direct incoherent pumping into the top level is avoided by the advantage of coherent pumping.In this model,the lower level of the probe transition is an excited state but not the usual ground state.By analytical as well as numerical calculations,we find that the probe gain,either with or without population inversion,which depends on the relation between spontaneous decay rates γ42 and γ21,can be achieved with proper parameters.we note that the Raman Scattering gain always plays an important role in achieving the rpobe amplification.
We have studied gain without population inversion in two similar four-level systems by employing semiclassical density-matrix formalism. If the incoherent pumping process is not taken into account, both systems can be visualized as an ideal V-type system. Along with the application of strong pump and weak probe fields, an incoherent pump field is added to each of the systems in a different configuration. It has been shown that the different mechanisms of application of an incoherent pump to the system can appreciably change the population difference between the energy levels of the strongly driven transition and results in the evolution of inversionless gain either at the line center or at the sidebands on probe detuning. The effect of inhomogeneous broadening on the probe gain has also been studied.
We demonstrate amplification without inversion in the 87Rb D1-line pumped by an incoherent light. A closed N-type, four-level atomic system has been considered to obtain an insight into the origin of the gain as well as the conditions under which the system exhibits gain without population inversion in bare states. We investigate the gain as a function of the incoherent pumping rate, the coupling laser detuning, and Rabi frequency. The experimental results are in good agreement with the numerical calculations considering the velocity distribution of atoms.
For a four-level atomic system with a doublet of closely spaced levels, we find that, owing to the coherence that results from the vacuum of the radiation field, population trapping at excited levels and probe gain with population inversion can be achieved with weak incoherent pumping. This gain is different from both the conventional lasing gain and gain without inversion in that there exists population inversion on probe transitions but the inversion is achieved by the vacuum-induced coherence.