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

Chinese Physics

Absorption properties of a driven four-level doppler-broadened system

Yuan Cheng Shi, Jin‐Hui Wu, Gao Jin-Yue

Published Apr 1, 2001• 7 citations
Publisher

Abstract

This paper deals with the absorption spectra of a weak probe in a four-level Doppler-broadened system driven by three coherent fields. The main aim is to extend earlier studies of the spontaneous emission spectrum and to present a comprehensive survey of the spectral features of this system. In addition to a derivation of exact formulae for the spectra, we give an explanation with the help of an appropriate set of dressed atomic states. We also get a deeper insight into the physical origin of gain in view of the existence of a population inversion between the levels of the lasing transition. Finally, we explore the effect of Doppler broadening on the absorption profile of the weak probe.

DOI
10.1088/1009-1963/10/4/307

Related papers

Spontaneous emission and absorption properties of a driven three-level system. II. The Λ and cascade models

Aaron S. Manka, Heide Doss, Lorenzo M. Narducci +2 more

This paper is concerned with the spectral profile of spontaneously emitted radiation from \ensuremath{\Lambda} and cascade models of driven three-level atoms, and with the absorption spectra of a weak probe. The atoms are excited by a pair of coherent external fields that are resonant or nearly resonant with the two dipole-allowed transitions of each of these two models. The main aim of this work is to extend earlier studies of the V-model configuration of three-level atoms and to present a comprehensive survey of the emission and absorption features of these systems. In addition to a derivation of exact formulas for the spectra and explicit analytic approximations in the high-intensity limit, we provide an explanation for the existence of simultaneous stationary population inversion between pairs of atomic levels and explore the effect of Doppler broadening on the absorption profile of the weak probe. In view of the latter analysis, in particular, we conclude that gain features persist even in the presence of inhomogeneous broadening. This suggests the possibility of experimental tests in a cell rather than an atomic-beam environment.

Physical Review A•Apr 1, 1991•114 citations

Spontaneous emission and absorption properties of a driven three-level system

Lorenzo M. Narducci, Marlan O. Scully, Gian‐Luca Oppo +2 more

We investigate the steady-state spontaneous emission spectrum of a three-level atom driven by two coherent fields and the absorption spectrum of a weak probe passing through a collection of such driven atoms. We find that the fluorescence spectrum is strongly affected by the decay rates of all the levels involved in the atomic evolution and not just by the decay parameters of the specific transition whose emission spectrum is being monitored. In particular, the spectral components can acquire very different widths and peak heights relative to the case of the standard resonance fluorescence in which a two-level system is driven by a single near-resonant field. An external probe signal passing through the gas of three-level atoms may be absorbed or amplified, as in the standard two-level case, but under specific operating conditions, amplification (or absorption) occurs over the entire range where the atomic response is appreciable. In this case the existence of amplification or absorption is controlled solely by the population difference between two dressed states of the system. We provide numerical results in support of our arguments for arbitrary values of the atomic and field parameters and also develop an analytic description in the limit of strong driving fields that leads to explicit line-shape and linewidth formulas.

Physical Review A•Aug 1, 1990•284 citations

Influence of Doppler broadening and spontaneously generated coherence on propagation effect in a quasi lambda-type four-level system

Zhongbo Liu, Ying Liang, Kening Jia +1 more

In this paper we study influences of Doppler broadening, spontaneously generated coherence, and other system parameters on propagation effect in a quasi lambda-type four-level atomic system. It is shown that when the Doppler broadening is present, generally speaking, the values of gain and intensity of lasing without inversion (i.e. the probe field) in the co-propagating probe and driving fields case are much larger than those in the counter-propagating case; considerably larger gain and intensity of lasing without inversion than those without the Doppler broadening can be obtained by choosing appropriate values of the Doppler broadening width and spontaneously generated coherence strength. The gain and intensity of lasing without inversion increase with the increase of spontaneously generated coherence strength; when spontaneously generated coherence is present, much larger gain and intensity of lasing without inversion than those in the case without spontaneously generated coherence can be obtained. Choosing suitable values of the probe detuning, Rabi frequencies of the driving and pump fields at the entrance of the medium also can remarkably enhance the gain and intensity of lasing without inversion.

Chinese Physics B•Feb 1, 2012•5 citations

Emission and absorption spectra in cascade and lambda models of driven atoms

Heide Doss, A. Manka, P. Ru +3 more

The coherent coupling of atomic levels under the action of driving electromagnetic fields is known to create unusual and interesting effects, such as the well-known population trapping phenomenon and subnatural line narrowing. In this paper we discuss two alternative configurations of three-level atoms, the cascade model and the inverted-V (lambda) model, in an effort to provide alternative options for experimental tests. In both cases we focus on the fluorescent emission spectrum of atom driven by two resonant fields and on the absorption spectrum of a weak probe passing through a gas in such a driven system. Subnatural line narrowing can be obtained from the cascade system but not from the lambda system. The lambda system, however, is characterized by strong population trapping so that it is not suitable for fluorescence studies (except out of resonance) because of its strongly reduced emission rate. The absorption spectrum of a weak probe displays gain features under high field conditions which suggest that useful amplification of a probe or laser-like emission should be possible over appropriate frequency ranges. We give a physical interpretation of the origin of the gain and explain why that in the case of a lambda system, but not a cascade system, steady-state population inversion can be obtained between both excited states relative to the lowest state of the atom. We also discuss the effect of Doppler broadening on the predicted emission and absorption lineshapes.

Annual Meeting Optical Society of America•Jan 1, 1990•0 citations

Spontaneous emission of a driven four-level Doppler broadened system

Yuan Shi, Jin-Yue Gao

We have studied the steady spontaneous emission spectrum of a four-level Doppler-broadened system driven by three coherent fields. It is found that the fluorescence spectrum is composed of nine contributions. The spectral components have quite different widths and peak heights compared with the case of the standard driven two-level or three-level resonance fluorescence. We provide numerical results in support of our arguments for arbitrary values of the atomic and field parameters.

Chinese Physics•Jun 1, 2000•4 citations

Effect of Doppler broadening on optical gain without inversion in a four-level model

Dezhong Wang, Jin-Yue Gao

We discuss the effect of Doppler broadening on the gain and refractive index experienced by an optical probe when passing through a collection of atoms in the absence of a population inversion. We calculate the gain-absorption spectrum of the medium when the atoms have a Maxwell velocity distribution and compare the atomic response when the pump and probe beams are arranged in copropagating and counterpropagating configurations. The results in these two cases can be qualitatively very different from each other, as we show with the help of numerical calculations. A physical interpretation and the conditions for the validity of the results are provided.

Physical Review A•Oct 1, 1995•15 citations
This paper deals with the absorption spectra of a weak probe in a four-level Doppler-broadened system driven by three coherent fields. The main aim is to extend earlier studies of the spontaneous emission spectrum and to present a comprehensive survey of the spectral features of this system. In addition to a derivation of exact formulae for the spectra, we give an explanation with the help of an appropriate set of dressed atomic states. We also get a deeper insight into the physical origin of gain in view of the existence of a population inversion between the levels of the lasing transition. Finally, we explore the effect of Doppler broadening on the absorption profile of the weak probe.
This paper is concerned with the spectral profile of spontaneously emitted radiation from \ensuremath{\Lambda} and cascade models of driven three-level atoms, and with the absorption spectra of a weak probe. The atoms are excited by a pair of coherent external fields that are resonant or nearly resonant with the two dipole-allowed transitions of each of these two models. The main aim of this work is to extend earlier studies of the V-model configuration of three-level atoms and to present a comprehensive survey of the emission and absorption features of these systems. In addition to a derivation of exact formulas for the spectra and explicit analytic approximations in the high-intensity limit, we provide an explanation for the existence of simultaneous stationary population inversion between pairs of atomic levels and explore the effect of Doppler broadening on the absorption profile of the weak probe. In view of the latter analysis, in particular, we conclude that gain features persist even in the presence of inhomogeneous broadening. This suggests the possibility of experimental tests in a cell rather than an atomic-beam environment.
We investigate the steady-state spontaneous emission spectrum of a three-level atom driven by two coherent fields and the absorption spectrum of a weak probe passing through a collection of such driven atoms. We find that the fluorescence spectrum is strongly affected by the decay rates of all the levels involved in the atomic evolution and not just by the decay parameters of the specific transition whose emission spectrum is being monitored. In particular, the spectral components can acquire very different widths and peak heights relative to the case of the standard resonance fluorescence in which a two-level system is driven by a single near-resonant field. An external probe signal passing through the gas of three-level atoms may be absorbed or amplified, as in the standard two-level case, but under specific operating conditions, amplification (or absorption) occurs over the entire range where the atomic response is appreciable. In this case the existence of amplification or absorption is controlled solely by the population difference between two dressed states of the system. We provide numerical results in support of our arguments for arbitrary values of the atomic and field parameters and also develop an analytic description in the limit of strong driving fields that leads to explicit line-shape and linewidth formulas.
In this paper we study influences of Doppler broadening, spontaneously generated coherence, and other system parameters on propagation effect in a quasi lambda-type four-level atomic system. It is shown that when the Doppler broadening is present, generally speaking, the values of gain and intensity of lasing without inversion (i.e. the probe field) in the co-propagating probe and driving fields case are much larger than those in the counter-propagating case; considerably larger gain and intensity of lasing without inversion than those without the Doppler broadening can be obtained by choosing appropriate values of the Doppler broadening width and spontaneously generated coherence strength. The gain and intensity of lasing without inversion increase with the increase of spontaneously generated coherence strength; when spontaneously generated coherence is present, much larger gain and intensity of lasing without inversion than those in the case without spontaneously generated coherence can be obtained. Choosing suitable values of the probe detuning, Rabi frequencies of the driving and pump fields at the entrance of the medium also can remarkably enhance the gain and intensity of lasing without inversion.
The coherent coupling of atomic levels under the action of driving electromagnetic fields is known to create unusual and interesting effects, such as the well-known population trapping phenomenon and subnatural line narrowing. In this paper we discuss two alternative configurations of three-level atoms, the cascade model and the inverted-V (lambda) model, in an effort to provide alternative options for experimental tests. In both cases we focus on the fluorescent emission spectrum of atom driven by two resonant fields and on the absorption spectrum of a weak probe passing through a gas in such a driven system. Subnatural line narrowing can be obtained from the cascade system but not from the lambda system. The lambda system, however, is characterized by strong population trapping so that it is not suitable for fluorescence studies (except out of resonance) because of its strongly reduced emission rate. The absorption spectrum of a weak probe displays gain features under high field conditions which suggest that useful amplification of a probe or laser-like emission should be possible over appropriate frequency ranges. We give a physical interpretation of the origin of the gain and explain why that in the case of a lambda system, but not a cascade system, steady-state population inversion can be obtained between both excited states relative to the lowest state of the atom. We also discuss the effect of Doppler broadening on the predicted emission and absorption lineshapes.
We discuss the effect of Doppler broadening on the gain and refractive index experienced by an optical probe when passing through a collection of atoms in the absence of a population inversion. We calculate the gain-absorption spectrum of the medium when the atoms have a Maxwell velocity distribution and compare the atomic response when the pump and probe beams are arranged in copropagating and counterpropagating configurations. The results in these two cases can be qualitatively very different from each other, as we show with the help of numerical calculations. A physical interpretation and the conditions for the validity of the results are provided.