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

Quantum Electronics and Laser Science Conference

Amplification without inversion in a three-level medium

Olga A. Kocharovskaya, Paul Mandef, Shuban Zhang

Published May 12, 1991• 0 citations
OpenAlex

Abstract

An attractive idea that has been widely discussed recently is to convert a low-frequency (LF) coherent input into a high-frequency coherent output without population inversion in tire medium.1-3 The simplest scheme for realizing this idea is a three-level medium in which a microwave field acts on tire LF transition and amplification occurs at either one or both optical transitions.

Related papers

Amplification without inversion in a multilevel medium

Paul Mandel, Olga A. Kocharovskaya

In a two-level medium, the condition for amplification is population inversion. The simplest scheme in which inversionless amplification occurs is a three-level medium. It was shown recently that a trichromatic field can be amplified by a three-level medium without population inversion if the low-frequency (LF) coherence exceeds some critical value.1 The question that we address here is how to generalize the two-level amplification condition when one or both levels are split into a number of sublevels.

Quantum Electronics and Laser Science Conference•May 12, 1991•0 citations

Inversionless amplification in a three-level medium

Olga A. Kocharovskaya, Paul Mandel, Yevgeny V. Radeonychev

We study all possible resonant three-level configurations where a low-frequency coherent pump can be converted into a high-frequency field in the absence of population inversion at both atomic high-frequency transitions. We identify two different mechanisms that provide such inversionless amplification.

Physical Review A•Feb 1, 1992•115 citations

Inversionless amplification in the three-level atoms with and without a hidden inversion in reservoir

Olga A. Kocharovskaya, Yuri V. Rostovtsev, Ataç İmamoğlu

We consider the problem of amplification without inversion in a three-level atomic system. When atoms are driven by a field reservoir and a low-frequency coherent field, amplification of a high-frequency probe field may occur even when there is no population inversion on any atomic transition. We prove that, depending on the ratio of the probe and coherent drive field frequencies, which we term the frequency up-conversion factor, this process may or may not require hidden inversion in the field reservoir. In the special case of a frequency up-conversion factor less than 2, we demonstrate that amplification is possible even if the field reservoir is in complete thermal equilibrium: this represents a new kind of coherent radiation source, distinct from both conventional lasers and lasers without inversion.

Physical Review A•Jul 1, 1998•26 citations

Amplification without inversion: The double-Λ scheme

Olga A. Kocharovskaya, Paul Mandel

We study the propagation of a bichromatic field in three-level and four-level media. In the case of a three-level medium, we consider the \ensuremath{\Lambda} configuration and demonstrate that if the upper level is not empty there is a critical value for the low-frequency coherence such that below this threshold and for intense fields, coherent bleaching occurs. This implies a sharp reduction of the field absorption and the fluorescence emission whereas above this threshold a parametric instability takes place. It corresponds to an amplification of the field that does not need a population inversion between the optical transitions. Finally we prove that the field alone cannot create a low-frequency coherence exceeding this threshold. Therefore we analyze the double-\ensuremath{\Lambda} configuration involving a four-level medium in which the upper and lower pairs of atomic levels have a low-frequency separation while optical transitions take place between the two pairs of states. An intense bichromatic field that is resonant with one upper state and the lower levels and a weak bichromatic field resonant with the other upper state and the same two lower states are sent into the medium. We analyze the limit in which the low-frequency coherence created between the lower pair of states has a relaxation time which is large. Then there will be population trapping in the lower states leading to coherent bleaching if there is no inversion between the upper levels but there will be amplification if there is inversion between the upper levels. In this way amplification at the optical transitions without population inversion between these states is realized.

Physical Review A•Jul 1, 1990•308 citations

Amplification without population inversion

Olga A. Kocharovskaya, Paul Mandel, Yakov I. Khanin

Three- and four-level schemes of inversionless amplification with different types of coherent pumping is reviewed. Amplification without inversion between the 'bare' states is a result of population inversion between eigenstates of the density matrix. In particular, it can be achieved due to the coherent population trapping, i.e., effective removal from the interaction with the field a fraction of atoms at lower levels.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Dec 16, 1992•2 citations

Coherent amplification of an ultrashort pulse in a three-level medium without a population inversion

Olga A. Kocharovskaya, Ya I Khanin

•Dec 1, 1988•56 citations
An attractive idea that has been widely discussed recently is to convert a low-frequency (LF) coherent input into a high-frequency coherent output without population inversion in tire medium.1-3 The simplest scheme for realizing this idea is a three-level medium in which a microwave field acts on tire LF transition and amplification occurs at either one or both optical transitions.
In a two-level medium, the condition for amplification is population inversion. The simplest scheme in which inversionless amplification occurs is a three-level medium. It was shown recently that a trichromatic field can be amplified by a three-level medium without population inversion if the low-frequency (LF) coherence exceeds some critical value.1 The question that we address here is how to generalize the two-level amplification condition when one or both levels are split into a number of sublevels.
We consider the problem of amplification without inversion in a three-level atomic system. When atoms are driven by a field reservoir and a low-frequency coherent field, amplification of a high-frequency probe field may occur even when there is no population inversion on any atomic transition. We prove that, depending on the ratio of the probe and coherent drive field frequencies, which we term the frequency up-conversion factor, this process may or may not require hidden inversion in the field reservoir. In the special case of a frequency up-conversion factor less than 2, we demonstrate that amplification is possible even if the field reservoir is in complete thermal equilibrium: this represents a new kind of coherent radiation source, distinct from both conventional lasers and lasers without inversion.
We study the propagation of a bichromatic field in three-level and four-level media. In the case of a three-level medium, we consider the \ensuremath{\Lambda} configuration and demonstrate that if the upper level is not empty there is a critical value for the low-frequency coherence such that below this threshold and for intense fields, coherent bleaching occurs. This implies a sharp reduction of the field absorption and the fluorescence emission whereas above this threshold a parametric instability takes place. It corresponds to an amplification of the field that does not need a population inversion between the optical transitions. Finally we prove that the field alone cannot create a low-frequency coherence exceeding this threshold. Therefore we analyze the double-\ensuremath{\Lambda} configuration involving a four-level medium in which the upper and lower pairs of atomic levels have a low-frequency separation while optical transitions take place between the two pairs of states. An intense bichromatic field that is resonant with one upper state and the lower levels and a weak bichromatic field resonant with the other upper state and the same two lower states are sent into the medium. We analyze the limit in which the low-frequency coherence created between the lower pair of states has a relaxation time which is large. Then there will be population trapping in the lower states leading to coherent bleaching if there is no inversion between the upper levels but there will be amplification if there is inversion between the upper levels. In this way amplification at the optical transitions without population inversion between these states is realized.