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

Applied Sciences

Influence of Magnetic Field on Amplification without Inversion Induced by a Femtosecond Pulse Train

Qianqian Ji, Rui Ma, Tianwei Jiang, Bin Luo

Published Feb 9, 2022• 0 citations
Publisher

Abstract

Taking advantage of the short pulse duration and the high repetition rate of the fs pulse train, amplification without inversion (AWI) can be achieved in two- or three-level atomic systems. A modulation method using a static magnetic field to control such AWI gain in an atomic system is proposed. The schematic model of the 52S1/2−52P1/2 transition of 87Rb is adopted, and the results show that the system gain can be significantly enhanced and modulated by the magnetic field, while the population inversion can be almost completely suppressed. Moreover, the pulse number, pulse repetition period, and pulse area can also be utilized to modulate the AWI gain.

DOI
10.3390/app12041780

Related papers

Observation of inversionless amplification in Sm vapour and related experiments

Wulfhard K. Lange, A. Nottelmann, C. Peters

An experiment is presented which demonstrates 'amplification without inversion' (AWI) and 'inversion without amplification' of a picosecond pulse in a generalized lambda-type system. The phenomena are based on Zeeman coherence in the J=1-level of the ground state multiplet in samarium, induced by a picosecond pulse train. The experiment and its relation to other AWI proposals and to previous experiments in atomic spectroscopy are discussed in detail.

Quantum Optics Journal of the European Optical Society Part B•Aug 1, 1994•7 citations

Amplification without inversion with two coherent coupling lasers in a four-level atom

Po Dong, Sing Hai Tang, Weining Man +1 more

We show that amplification without inversion (AWI) can be realized with two coherent driving lasers in a four-level atom. With the help of quantum-jump theory, two transition processes are found to contribute to the absorption or gain behaviour. It is explicitly shown that an asymmetry between the three-photon stimulated emission and the single-photon absorption process leads to AWI. Furthermore, it is demonstrated that AWI can occur in this model with or without quantum interference. The origin of AWI without interference is explained by introducing weights for dressed-state transitions. The asymmetry between the weights for a dressed-state transition in absorption and its counterpart in emission leads to the possibility of AWI.

Journal of Physics B Atomic Molecular and Optical Physics•Jul 11, 2001•5 citations

Slow light propagation in an atomic vapour under conditions of amplification without inversion

Kyoung-Dae Kim, Feng Xiao, Chung Hee Lee +3 more

We report experimental results on slowing a light pulse in a system for amplification without inversion (AWI). We were able to control a subluminal group velocity continuously from V g = c /2850 to c /7260 by just changing an incoherent pumping beam power from 0 to 12 mW in the AWI system. And several advantages, such as the controllable delay time and the pulse amplification, for slowing of the light in the AWI system compared to in an electromagnetically induced transparency system were found.

Journal of Physics B Atomic Molecular and Optical Physics•Jun 10, 2003•14 citations

Influence of field-dependent relaxation on amplification without inversion

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

We study a three-level atomic system strongly driven by a monochromatic field resonant to one of atomic transitions. The second highest frequency transition is probed by a weak field. In such a system we predict a novel mechanism of probe field amplification without inversion via strong field induced spontaneous relaxation of the ground atomic state. Unlike the AWI in the (Lambda) -scheme this mechanism appears in case of sufficiently fast relaxation at the low frequency transition.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•May 10, 1996•0 citations

Effects of incoherent pumping on the phase control of amplification without inversion in a Λ system with spontaneously generated coherence

Yanfeng Bai, Hong Mei Guo, Dingan Han +1 more

The effects of incoherent pumping on the phase control of amplification without inversion (AWI) are investigated in a three-level Λ system with a weak probe field. It is shown that, similar to spontaneously generated coherence, incoherent pumping is necessary to make the system become sensitive to the relative phase. We find that the region in which AWI can be exhibited is widened with the enhancement of incoherent pumping, and that the amplitude of the probe gain can be also changed where there exists an extremum of the amplitude for a given probe detuning.

Journal of Optics B Quantum and Semiclassical Optics•Jan 7, 2005•33 citations

Amplification without Inversion Enhanced Rydberg‐Atom‐Based Detection of Microwave Electric Fields

Yingfan Wang, Zhengmao Jia, Jianfei Tian +3 more

ABSTRACT A quantum‐enhanced scheme for microwave (MW) electric (E) field detection is theoretically proposed, utilizing transient amplification without inversion (AWI) in cold 87 Rb atoms. It is achieved by modulating a continuous‐wave coupling laser into a periodic near‐square‐wave pulse, which enables precise control over quantum coherence and induces transient gain. Simulation results demonstrate significant performance enhancements of the AWI scheme compared to conventional electromagnetically induced transparency (EIT) approaches. In comparison, the AWI scheme shows 7.3 times enhanced transient transmission intensity. The reduction of the full width at half maximum from 0.54 × 2π to 0.15 × 2π MHz represents a 72% narrowing of the spectral linewidth, which enables superior spectral resolution and extends the range of measurable Autler‐Townes splitting. Furthermore, the minimum detectable MW E‐field strength of 172.8 nV cm −1 represents an order of magnitude improvement. The robustness of the AWI signal against simulated technical noise is also confirmed. The demonstrated capabilities establish AWI as a promising technique for high‐sensitivity quantum MW electrometry.

Advanced Quantum Technologies•Feb 1, 2026•0 citations
Taking advantage of the short pulse duration and the high repetition rate of the fs pulse train, amplification without inversion (AWI) can be achieved in two- or three-level atomic systems. A modulation method using a static magnetic field to control such AWI gain in an atomic system is proposed. The schematic model of the 52S1/2−52P1/2 transition of 87Rb is adopted, and the results show that the system gain can be significantly enhanced and modulated by the magnetic field, while the population inversion can be almost completely suppressed. Moreover, the pulse number, pulse repetition period, and pulse area can also be utilized to modulate the AWI gain.
We show that amplification without inversion (AWI) can be realized with two coherent driving lasers in a four-level atom. With the help of quantum-jump theory, two transition processes are found to contribute to the absorption or gain behaviour. It is explicitly shown that an asymmetry between the three-photon stimulated emission and the single-photon absorption process leads to AWI. Furthermore, it is demonstrated that AWI can occur in this model with or without quantum interference. The origin of AWI without interference is explained by introducing weights for dressed-state transitions. The asymmetry between the weights for a dressed-state transition in absorption and its counterpart in emission leads to the possibility of AWI.
The effects of incoherent pumping on the phase control of amplification without inversion (AWI) are investigated in a three-level Λ system with a weak probe field. It is shown that, similar to spontaneously generated coherence, incoherent pumping is necessary to make the system become sensitive to the relative phase. We find that the region in which AWI can be exhibited is widened with the enhancement of incoherent pumping, and that the amplitude of the probe gain can be also changed where there exists an extremum of the amplitude for a given probe detuning.
ABSTRACT A quantum‐enhanced scheme for microwave (MW) electric (E) field detection is theoretically proposed, utilizing transient amplification without inversion (AWI) in cold 87 Rb atoms. It is achieved by modulating a continuous‐wave coupling laser into a periodic near‐square‐wave pulse, which enables precise control over quantum coherence and induces transient gain. Simulation results demonstrate significant performance enhancements of the AWI scheme compared to conventional electromagnetically induced transparency (EIT) approaches. In comparison, the AWI scheme shows 7.3 times enhanced transient transmission intensity. The reduction of the full width at half maximum from 0.54 × 2π to 0.15 × 2π MHz represents a 72% narrowing of the spectral linewidth, which enables superior spectral resolution and extends the range of measurable Autler‐Townes splitting. Furthermore, the minimum detectable MW E‐field strength of 172.8 nV cm −1 represents an order of magnitude improvement. The robustness of the AWI signal against simulated technical noise is also confirmed. The demonstrated capabilities establish AWI as a promising technique for high‐sensitivity quantum MW electrometry.