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

Soviet Journal of Quantum Electronics

Spatial evolution of cooperative Raman scattering

Anatolii V Andreev, Yu A Il'inskiĭ, A. S. Mkoyan

Published Apr 30, 1989• 0 citations
Publisher

Abstract

A semiclassical system of equations is derived in the two-wave approximation describing the dynamics of evolution of cooperative Raman scattering (CRS). Relaxation and parametric processes, inhomogeneous broadening effects, and propagation processes are taken into account. An investigation is made of the influence of parametric processes and progagation effects on the CRS process. Strong amplitude and phase modulation of the scattered field pulses is predicted. A continuous transition from CRS to quasisteady-state stimulated Raman scattering is described.

DOI
10.1070/qe1989v019n04abeh007901

Related papers

Molecular cooperation in the transient regime of stimulated Raman scattering

Michael G. Raymer, Ian A. Walmsley

The nonlinear regime of stimulated Raman scattering (SRS) may be reached in two ways. The best known is that of depletion of the pump laser as a large number of photons are scattered into the Stokes field. There is, however, another way in which gain saturation can occur, that is, by depletion of the atomic population while the laser remains undepleted. The equations which describe SRS, including damping and population inversion,1 are remarkably similar to those of well-known theories of two-level superfluorescence, and it is possible by analogy to define a delay time τ D for cooperative Raman scattering (CRS). This delay time is inversely proportional to the spontaneous scattering rate, which depends on the pump laser intensity. A sufficient condition for CRS is that the spontaneous Stokes linewidth Γ is very much greater than τ D − 1 . The only other requirement is that there be more laser photons than scatterers, so that τ D is independent of the number of scatterers. The S(1) transition in molecular hydrogen, when excited by a short (≅ 100-ps) laser pulse, provides a possible system for observing pure CRS. Similar studies have been carried out previously2 for Γ ≅ τ D − 1 .

Annual Meeting Optical Society of America•Jan 1, 1985•0 citations

Effect of phase self-modulation of light on cooperative Raman scattering

Sergei G Rautian, B. M. Chernobrod

An investigation is made of the influence of time modulation of the permittivity of a medium, induced by a high-power scattering field pulse, on the temporal characteristics of cooperative scattering. It is shown that the resultant phase self-modulation increases the delay time and reduces slightly the pulse duration of the cooperative scattering intensity.

Soviet Journal of Quantum Electronics•Dec 31, 1979•0 citations

Stimulated Raman scattering by a pointlike medium: Classical and quantum treatments

David J. Kaup, Alexander E. Kozhekin, V. I. Rupasov

The exact solutions of both the classical and quantum versions of two models describing stimulated Raman scattering in the spatially homogeneous approximation are obtained. The quantum problem is a dynamical problem and the exact solution for the out-states of this problem is presented. We also include medium dissipation and inhomogeneous broadening of the resonance transition and present the solution of that quantum problem. The expectation value of the intensity of the generated Stokes pulse is obtained and discussed. The recursion relation for the expectation value of a general nodal operator is given and it is solved, with the solution being given as either an infinite sum or a contour integral. \textcopyright{} 1996 The American Physical Society.

Physical Review A•Jan 1, 1996•0 citations

A model of nonstationary backward stimulated Raman scattering in an extended system: Interaction of forward and backward Stokes waves

N. I. Shamrov

A semiclassical model of nonstationary stimulated Raman scattering with account of forward and backward waves of different frequencies is proposed. Equations for the elements of a collective density matrix and electric-field amplitudes are obtained applying the averaging method. It is shown that forward waves are generated by a united polarization component, whereas each of the backward waves is formed by its own component. The description is based on the approximation of small scattering angles and assumes that the quantities considered do not depend on transverse coordinates. The emission dynamics of forward-backward Stokes pulses is investigated both for the linear case and under the strong depletion of pumping and level populations. The domain of applicability of the model of nonstationary forward stimulated Raman scattering is determined.

Optics and Spectroscopy•Oct 1, 2008•2 citations

Solitons in Stimulated Raman Scattering

Heinz Steudel

Abstract The semiclassical equations of SRS are derived by the following method: The many‐level molecule is described by the Schrödinger equation and subsequently all amplitudes but those of the essential two levels are eliminated by approximate integration. Especially the case of equal group velocities for pump and Stokes wave is considered. Terms describing a frequency shift due to dynamical Stark effect and a change of refraction index by vibrational excitation can be removed by a suitable transformation. Under various, physically different, assumptions the system of molecular and field equations is reduced to the equations describing a quasimonochromatic pulse propagating in a resonant two‐level system, and in this way we can find a rich manifold of solutions. E.g., the 2π‐pulse of self‐induced transparency can be transferred to SRS. By other assumptions we are led to equations defining the Bäcklund transformation for the sine‐Gordon equation. For this case also soliton type solutions can be constructed.

Annalen der Physik•Jan 1, 1977•32 citations

Stimulated Raman scattering in the approximation of unidirectional propagation in a medium with static dipole moments

Alexander A. Zabolotskii

The evolution equations of two-frequency stimulated Raman scattering in a molecular quasithree- level medium with static dipole moments have been derived in the approximations of the nondepletion of the pump field and the unidirectional propagation of the Stokes field. Completely integrable particular cases of the resulting system of equations have been found. New mechanisms of controlling the parameters of microwave pulses generated in such a system have been studied within this model. The numerical analysis and particular exact solutions demonstrate the possibility of switch between the regimes of generation of narrow Stokes field pulses and nearly rectangular pulses.

Journal of Experimental and Theoretical Physics•Jan 1, 2016•0 citations
A semiclassical system of equations is derived in the two-wave approximation describing the dynamics of evolution of cooperative Raman scattering (CRS). Relaxation and parametric processes, inhomogeneous broadening effects, and propagation processes are taken into account. An investigation is made of the influence of parametric processes and progagation effects on the CRS process. Strong amplitude and phase modulation of the scattered field pulses is predicted. A continuous transition from CRS to quasisteady-state stimulated Raman scattering is described.
The nonlinear regime of stimulated Raman scattering (SRS) may be reached in two ways. The best known is that of depletion of the pump laser as a large number of photons are scattered into the Stokes field. There is, however, another way in which gain saturation can occur, that is, by depletion of the atomic population while the laser remains undepleted. The equations which describe SRS, including damping and population inversion,1 are remarkably similar to those of well-known theories of two-level superfluorescence, and it is possible by analogy to define a delay time τ D for cooperative Raman scattering (CRS). This delay time is inversely proportional to the spontaneous scattering rate, which depends on the pump laser intensity. A sufficient condition for CRS is that the spontaneous Stokes linewidth Γ is very much greater than τ D − 1 . The only other requirement is that there be more laser photons than scatterers, so that τ D is independent of the number of scatterers. The S(1) transition in molecular hydrogen, when excited by a short (≅ 100-ps) laser pulse, provides a possible system for observing pure CRS. Similar studies have been carried out previously2 for Γ ≅ τ D − 1 .
The exact solutions of both the classical and quantum versions of two models describing stimulated Raman scattering in the spatially homogeneous approximation are obtained. The quantum problem is a dynamical problem and the exact solution for the out-states of this problem is presented. We also include medium dissipation and inhomogeneous broadening of the resonance transition and present the solution of that quantum problem. The expectation value of the intensity of the generated Stokes pulse is obtained and discussed. The recursion relation for the expectation value of a general nodal operator is given and it is solved, with the solution being given as either an infinite sum or a contour integral. \textcopyright{} 1996 The American Physical Society.
A semiclassical model of nonstationary stimulated Raman scattering with account of forward and backward waves of different frequencies is proposed. Equations for the elements of a collective density matrix and electric-field amplitudes are obtained applying the averaging method. It is shown that forward waves are generated by a united polarization component, whereas each of the backward waves is formed by its own component. The description is based on the approximation of small scattering angles and assumes that the quantities considered do not depend on transverse coordinates. The emission dynamics of forward-backward Stokes pulses is investigated both for the linear case and under the strong depletion of pumping and level populations. The domain of applicability of the model of nonstationary forward stimulated Raman scattering is determined.
Abstract The semiclassical equations of SRS are derived by the following method: The many‐level molecule is described by the Schrödinger equation and subsequently all amplitudes but those of the essential two levels are eliminated by approximate integration. Especially the case of equal group velocities for pump and Stokes wave is considered. Terms describing a frequency shift due to dynamical Stark effect and a change of refraction index by vibrational excitation can be removed by a suitable transformation. Under various, physically different, assumptions the system of molecular and field equations is reduced to the equations describing a quasimonochromatic pulse propagating in a resonant two‐level system, and in this way we can find a rich manifold of solutions. E.g., the 2π‐pulse of self‐induced transparency can be transferred to SRS. By other assumptions we are led to equations defining the Bäcklund transformation for the sine‐Gordon equation. For this case also soliton type solutions can be constructed.
The evolution equations of two-frequency stimulated Raman scattering in a molecular quasithree- level medium with static dipole moments have been derived in the approximations of the nondepletion of the pump field and the unidirectional propagation of the Stokes field. Completely integrable particular cases of the resulting system of equations have been found. New mechanisms of controlling the parameters of microwave pulses generated in such a system have been studied within this model. The numerical analysis and particular exact solutions demonstrate the possibility of switch between the regimes of generation of narrow Stokes field pulses and nearly rectangular pulses.