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

Annual Meeting Optical Society of America

Competition between coherent and incoherent nonlinear optical processes

Daniel J. Gauthier, Michelle S. Malcuit, Robert W. Boyd

Published Jan 1, 1985• 0 citations
Publisher

Abstract

Competition has been observed between amplified spontaneous emission (ASE) and four-wave mixing (FWM). Previously, competition between an incoherent and coherent process was observed in the form of suppression of multiphoton ionization by third harmonic generation.1,2 In our experiment, an input laser was tuned precisely to the 3s → 3d two-photon allowed transition in atomic sodium vapor and the emission was observed in both the forward and backward directions. In these conditions, either FWM or ASE can occur. Ignoring the possibility of competition between these two processes, the calculated gain for ASE is much larger than that for FWM. However, we have observed experimentally that FWM and not ASE occur. To determine that it is the presence of efficient FWM that suppresses ASE, we have excited the atomic vapor instead with counterpropagating pump waves of different frequency. In this case, FWM, being a phase-matched process, cannot occur and strong ASE is observed. The nature of this competition is explained by solving the coupled Maxwell and density matrix equations for a three-level system. It is found that the suppression is due to the destructive interference between two different pathways of excitation of the 3d level which results in trapping of the population in the ground state.

DOI
10.1364/oam.1985.tux5

Related papers

Competition between amplified spontaneous emission and the four-wave-mixing process

Robert W. Boyd, Michelle S. Malcuit, Daniel J. Gauthier +1 more

Competition between amplified spontaneous emission (ASE) and the four-wave-mixing (FWM) process has been observed under conditions of two-photon resonant excitation of the sodium 3d level. The nature of the competition is that the FWM process is able to prevent the occurrence of ASE, even though the gain of the ASE process calculated in the absence of competition effects is much larger than that of FWM. The ASE is suppressed because the fields generated by the FWM process create a new excitation pathway connecting the ground and 3d levels, and under quite general conditions this pathway interferes destructively with that due solely to the applied laser field. These effects are modeled theoretically by solving perturbatively the density-matrix equations of the atomic system, thereby determining the population in the upper level and the nonlinear polarization of the medium. The coupling between the various optical fields due to the nonlinear polarization is described by coupled amplitude equations. The solution to these equations predicts that when the wave-vector mismatch is not too large the fields evolve spatially to reach steady-state values, and that the population excited to the 3d level by the total steady-state optical field is much smaller than that due to the incident laser field alone. We have observed experimentally the suppression of ASE by FWM and have observed that this suppression does not occur when the medium is excited with counterpropagating beams that cannot efficiently excite the FWM process. In addition, we have conducted a series of experiments that shows that the degree of suppression of ASE depends on the intensity and focusing characteristics of the incident laser as expected on the basis of our theoretical model.

Physical Review A•Feb 1, 1987•118 citations

Competition between four-wave mixing and incoherent nonlinear optical processes

Michelle S. Malcuit, Daniel J. Gauthier, Robert W. Boyd

When a strong near-resonant laser beam propagates through an atomic vapor, it can simultaneously induce several different nonlinear optical processes. In certain restricted conditions, these processes evolve independently of one another, but in general these processes compete. We have observed competition1 between four-wave mixing2 (FWM) and amplified spontaneous emission3 (ASE) and have presented an explanation for this phenomenon based on the solution of the coupled-amplitude equations of nonlinear optics. We extend our previous work by presenting a more detailed theoretical explanation of this effect and evidence that competition of this sort occurs quite generally in nonlinear optical systems.

Journal of the Optical Society of America B•Jan 1, 1986•0 citations

Suppression of Amplified Spontaneous Emission by the Four-Wave Mixing Process

Michelle S. Malcuit, Daniel J. Gauthier, Robert W. Boyd

Two-photon-resonant excitation of the sodium $3d$ level can lead to the generation of new frequencies either by amplified spontaneous emission at the $3d\ensuremath{\rightarrow}3p$ transition frequency or by a resonantly enhanced four-wave mixing process. Competition between these two processes has been observed. The four-wave mixing process can suppress amplified spontaneous emission by preventing the excitation of the $3d$ level due to an interference between two different pathways connecting the ground ($3s$) and $3d$ states.

Physical Review Letters•Sep 2, 1985•108 citations

Bidirectional description of amplified spontaneous emission induced by three-photon absorption

Alexander S. Baev, Viktor Kimberg, Sergey P. Polyutov +2 more

A semiclassical dynamic theory of the nonlinear propagation of a few interacting intense light pulses is applied to study the nonlinear counterpropagation of amplified spontaneous emission (ASE) induced by three-photon absorption of short intense laser pulses in a chromophore solution. Several important results from the modeling are reached for the ASE process developing in the regime of strong saturation. Accounting for ASE in both forward and backward directions with respect to the pump pulse results in a smaller efficiency of nonlinear conversion for the forward ASE compared with the case in which forward emission is considered alone, something that results from the partial repump of the absorbed energy to the backward ASE component; the overall efficiency is nevertheless higher than for the forward emission considered alone. The efficiency of nonlinear conversion of the pump energy to the counterpropagating ASE pulses is strongly dependent on the concentration of active molecules so that a particular combination of concentration versus cell length optimizes the conversion coefficient. Under certain specified conditions, the ASE effect is found to be oscillatory; the origin of oscillations is dynamical competition between stimulated emission and off-resonant absorption. This result can be considered one of the possible explanations of the temporal fluctuations of the forward ASE pulse [Nature 415, 767 (2002)].

Journal of the Optical Society of America B•Feb 1, 2005•8 citations

The observation of the competition and suppression for stimulated Raman scattering near the potassium 4S-5P resonance

Hau-wei Wang, Mao-Hong Lu

The competition of stimulated Raman scattering (SRS) between 4S-(5P)-5S and 4S-(3D)-5S channels has been observed as a laser is tuned near the 4S-5P resonance in potassium vapour. The experimental results show that SRS only occurs in the 4S-(5P)-5S channel. In this Raman scattering, suppression of the amplified spontaneous emission (ASE) (5S-4P) has been observed. The influence of the four-wave mixing (FWM) processes on the SRS is discussed. In the 4S-(5P)-3D channel, in the backward direction no detectable emission corresponding to SRS (4S-(5P)-3D) has been observed, so the forward (5P)-3D emission should be FWM, not SRS. The ASE (3D-4P) arises from the ASE (5P-3D), which can be observed in the backward direction.

Journal of Physics B Atomic Molecular and Optical Physics•Oct 31, 2000•2 citations

Competition and Energy Transfer Between Forward and Backward Four-Wave Mixing via Atomic Coherence

Lin Cheng, Yaling Tian, Yize Liu +4 more

Two four-wave mixing (FWM) processes with different directions and frequencies can coexist and interfere in a four-level inverted-Y-type atomic system, the generated FWM beams fall into two different electromagnetically induced transparency windows. We report Autler-Townes splitting and dressed suppression and enhancement of two generated FWM beams. In the case of matched slow FWM beams, two FWM processes compete and exchange their energies between them, the forward four-wave beam give its energy to the backward four-wave beam by interaction for long distance. Such studies of two FWM beams can have vital applications in studying the higher-order nonlinear optical processes, generating correlated photon pairs and quantum information processing.

IEEE Journal of Quantum Electronics•Mar 2, 2017•2 citations
Competition has been observed between amplified spontaneous emission (ASE) and four-wave mixing (FWM). Previously, competition between an incoherent and coherent process was observed in the form of suppression of multiphoton ionization by third harmonic generation.1,2 In our experiment, an input laser was tuned precisely to the 3s → 3d two-photon allowed transition in atomic sodium vapor and the emission was observed in both the forward and backward directions. In these conditions, either FWM or ASE can occur. Ignoring the possibility of competition between these two processes, the calculated gain for ASE is much larger than that for FWM. However, we have observed experimentally that FWM and not ASE occur. To determine that it is the presence of efficient FWM that suppresses ASE, we have excited the atomic vapor instead with counterpropagating pump waves of different frequency. In this case, FWM, being a phase-matched process, cannot occur and strong ASE is observed. The nature of this competition is explained by solving the coupled Maxwell and density matrix equations for a three-level system. It is found that the suppression is due to the destructive interference between two different pathways of excitation of the 3d level which results in trapping of the population in the ground state.
Competition between amplified spontaneous emission (ASE) and the four-wave-mixing (FWM) process has been observed under conditions of two-photon resonant excitation of the sodium 3d level. The nature of the competition is that the FWM process is able to prevent the occurrence of ASE, even though the gain of the ASE process calculated in the absence of competition effects is much larger than that of FWM. The ASE is suppressed because the fields generated by the FWM process create a new excitation pathway connecting the ground and 3d levels, and under quite general conditions this pathway interferes destructively with that due solely to the applied laser field. These effects are modeled theoretically by solving perturbatively the density-matrix equations of the atomic system, thereby determining the population in the upper level and the nonlinear polarization of the medium. The coupling between the various optical fields due to the nonlinear polarization is described by coupled amplitude equations. The solution to these equations predicts that when the wave-vector mismatch is not too large the fields evolve spatially to reach steady-state values, and that the population excited to the 3d level by the total steady-state optical field is much smaller than that due to the incident laser field alone. We have observed experimentally the suppression of ASE by FWM and have observed that this suppression does not occur when the medium is excited with counterpropagating beams that cannot efficiently excite the FWM process. In addition, we have conducted a series of experiments that shows that the degree of suppression of ASE depends on the intensity and focusing characteristics of the incident laser as expected on the basis of our theoretical model.
When a strong near-resonant laser beam propagates through an atomic vapor, it can simultaneously induce several different nonlinear optical processes. In certain restricted conditions, these processes evolve independently of one another, but in general these processes compete. We have observed competition1 between four-wave mixing2 (FWM) and amplified spontaneous emission3 (ASE) and have presented an explanation for this phenomenon based on the solution of the coupled-amplitude equations of nonlinear optics. We extend our previous work by presenting a more detailed theoretical explanation of this effect and evidence that competition of this sort occurs quite generally in nonlinear optical systems.
Two-photon-resonant excitation of the sodium 3d3d3d level can lead to the generation of new frequencies either by amplified spontaneous emission at the $3d\ensuremath{\rightarrow}3p$ transition frequency or by a resonantly enhanced four-wave mixing process. Competition between these two processes has been observed. The four-wave mixing process can suppress amplified spontaneous emission by preventing the excitation of the 3d3d3d level due to an interference between two different pathways connecting the ground (3s3s3s) and 3d3d3d states.
A semiclassical dynamic theory of the nonlinear propagation of a few interacting intense light pulses is applied to study the nonlinear counterpropagation of amplified spontaneous emission (ASE) induced by three-photon absorption of short intense laser pulses in a chromophore solution. Several important results from the modeling are reached for the ASE process developing in the regime of strong saturation. Accounting for ASE in both forward and backward directions with respect to the pump pulse results in a smaller efficiency of nonlinear conversion for the forward ASE compared with the case in which forward emission is considered alone, something that results from the partial repump of the absorbed energy to the backward ASE component; the overall efficiency is nevertheless higher than for the forward emission considered alone. The efficiency of nonlinear conversion of the pump energy to the counterpropagating ASE pulses is strongly dependent on the concentration of active molecules so that a particular combination of concentration versus cell length optimizes the conversion coefficient. Under certain specified conditions, the ASE effect is found to be oscillatory; the origin of oscillations is dynamical competition between stimulated emission and off-resonant absorption. This result can be considered one of the possible explanations of the temporal fluctuations of the forward ASE pulse [Nature 415, 767 (2002)].
The competition of stimulated Raman scattering (SRS) between 4S-(5P)-5S and 4S-(3D)-5S channels has been observed as a laser is tuned near the 4S-5P resonance in potassium vapour. The experimental results show that SRS only occurs in the 4S-(5P)-5S channel. In this Raman scattering, suppression of the amplified spontaneous emission (ASE) (5S-4P) has been observed. The influence of the four-wave mixing (FWM) processes on the SRS is discussed. In the 4S-(5P)-3D channel, in the backward direction no detectable emission corresponding to SRS (4S-(5P)-3D) has been observed, so the forward (5P)-3D emission should be FWM, not SRS. The ASE (3D-4P) arises from the ASE (5P-3D), which can be observed in the backward direction.
Two four-wave mixing (FWM) processes with different directions and frequencies can coexist and interfere in a four-level inverted-Y-type atomic system, the generated FWM beams fall into two different electromagnetically induced transparency windows. We report Autler-Townes splitting and dressed suppression and enhancement of two generated FWM beams. In the case of matched slow FWM beams, two FWM processes compete and exchange their energies between them, the forward four-wave beam give its energy to the backward four-wave beam by interaction for long distance. Such studies of two FWM beams can have vital applications in studying the higher-order nonlinear optical processes, generating correlated photon pairs and quantum information processing.