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 B

Dynamics of cooperative emissions in a cascade three-level molecular system driven by an ultrashort laser pulse

Ji‐Cai Liu, Wang Chun-Xin, Faris Gel’mukhanov, Chuan‐Kui Wang

Published Nov 1, 2008• 4 citations
Publisher

Abstract

This paper investigates the dynamics of cooperative emissions in a cascade three-level system driven by an ultrashort laser pulse by solving numerically the full-wave Maxwell–Bloch equations. The 4, 4'-bis(dimethylamino) stilbene molecule is used as the model molecule because of its strong two-photon absorption property. The two-colour cooperative emissions are studied as functions of molecular number density and dephasing rate of the dipole coherence. The propagation effects on the evolution of the cooperative radiations are also taken into account. The cooperative radiations are enhanced for large number density of the molecule, while the fast dephasing of the dipole coherence reduces the intensity of the cooperative radiations and delays the emission times or even inhibits the formation of the emissions. The delay time of the radiation decreases with the increase of the molecular number density and the propagation distance.

DOI
10.1088/1674-1056/17/11/043

Related papers

Dynamical behavior of two-color ultrashort laser pulses in a cascade three-level molecular system

Chuan‐Kui Wang

Using the finite-difference time domain technique(FDTD) for the fields and the predictor-corrector method for the material variables,we solve the Maxwell-Bloch equations beyond the slowly-varying envelope approximation and the rotating-wave approximation.4,4′-bis(dimethylamino) stilbene organic molecule is one type of one-dimensional symmetrical system and its electronic structure and parameters are calculated by density functional theory.The molecule can be simplified as a three-level system.By numerically simulating the propagation of two-color 2π ultrashort laser pulses in a cascade three-level organic molecule system,we analyze the temporal-spatial evolution properties of the ultrashort laser pulses and the population of each energy level under different resonant conditions.

Journal of Atomic and Molecular Physics•Jan 1, 2006•0 citations

Dynamical behavior of ultra-short laser pulse in a cascade three-level molecular system

Ji‐Cai Liu, Ke Zhao, Yuzhi Song +2 more

We study the interaction between the ultra-short laser pulses and the one-dimensional symmetrical π conjugated molecular material (4,4′-bis (dimethylamino) stilbene) by solving Maxwell-Bloch equations. This kind of molecular material has strong nonlinear optical properties, and its electronic structures and dipole moments are calculated by use of density functional theory on ab initio level. The numerical results show that the slowly varying envelope approximation and the rotating wave approximation cannot accurately describe the propagation properties of the ultra-short pulse in the molecular medium. In the case of single photon resonance, the two-level model can well describe the interaction between the small area pulse and the molecular system. For large area pulse, due to the existence of strongly secondary excitation to the higher-lying levels, the three-level model should be used. When the amplitude of the incident electric field is kept constant, the third level's population increases with the increase of the pulse area.

Acta Physica Sinica•Jan 1, 2006•8 citations

Resonant propagation of laser pulse in organic molecular material

Chuan‐Kui Wang

By use of Maxwell-Bloch coupled equations, we investigate the resonant propagation of laser pulse in 4,4′-bis(dimethylamino) stilbene organic molecular material. The spatial-temporal evolution of the laser pulse is numerically displayed. The damping effect resulted from inelastic or elastic collisions is considered.

Chinese journal of atomic and molecular physics•Jan 1, 2004•0 citations

Optical power limiting of ultrashort hyper-Gaussian pulses in cascade three-level system

Ji‐Cai Liu, Fen-Fen Guo, Ya-Nan Zhao +1 more

Propagation of strong femtosecond hyper-Gaussian pulses in a cascade three-level molecular system is studied by solving numerically the Maxwell–Bloch equations by the iterative predictor-corrector finite-difference time-domain method. Optical power limiting behavior induced by strong nonlinear two-photon absorption is observed for different orders of the femtosecond hyper-Gaussian pulses. Pulses of a higher order temporal profile are found to have a wider power range of optical limiting but a larger output saturation intensity. Both the output saturation value and the damage threshold of optical power limiting decrease with pulse duration increasing. The decrease of the pulse area along the pulse propagation is much slower than that obtained from the two-photon area theorem due to invalidity of the slowly varying amplitude approximation and the monochromatic field hypothesis.

Chinese Physics B•Oct 1, 2018•4 citations

Coherent propagation of intense ultrashort laser pulses in a molecular multilevel medium

Szczepan Chelkowski, André D. Bandrauk

The Maxwell–Schrödinger equations describing the ultrashort laser pulse propagation in multilevel molecular media are shown to be analytically solvable and to reduce to nonlinear multisine-Gordon equations for certain models of the field–molecule system. Special cases of level schemes are shown to lead to soliton propagation. A numerical study is presented in order to examine the effect of nonresonant (virtual) transitions on pulse propagation and amplification in a three-level molecular system as a function of intensity and detuning.

The Journal of Chemical Physics•Sep 15, 1988•30 citations

Theory of Cooperative Cascade Emission. I. Linear Stochastic Theory

Kensuke S. Ikeda, Jumpei Okada, Masahiro Matsuoka

The time evolution of the cascade omission from an assembly of the three-level atoms excited by two-photon process is investigated under a linear approximation. The propagation effect and the stochastic nature of the quantum noise are fully taken into account. It is found that the time evolution of the emitted radiation shows different behaviors in the three time stages: In the earliest stage a negative feedback mechanism due to the two-photon coherence is important, and the emitted radiation exhibits a characteristic growing behavior peculiar to the cascade system; in the intermediate one this mechanism is destroyed by the dephasing, and a superradiant growth begins; and finally in the latest one this growth is suppressed by the dephasing of the active polarization, and a stationary radiation appears.

Journal of the Physical Society of Japan•May 1, 1980•23 citations
This paper investigates the dynamics of cooperative emissions in a cascade three-level system driven by an ultrashort laser pulse by solving numerically the full-wave Maxwell–Bloch equations. The 4, 4'-bis(dimethylamino) stilbene molecule is used as the model molecule because of its strong two-photon absorption property. The two-colour cooperative emissions are studied as functions of molecular number density and dephasing rate of the dipole coherence. The propagation effects on the evolution of the cooperative radiations are also taken into account. The cooperative radiations are enhanced for large number density of the molecule, while the fast dephasing of the dipole coherence reduces the intensity of the cooperative radiations and delays the emission times or even inhibits the formation of the emissions. The delay time of the radiation decreases with the increase of the molecular number density and the propagation distance.
Using the finite-difference time domain technique(FDTD) for the fields and the predictor-corrector method for the material variables,we solve the Maxwell-Bloch equations beyond the slowly-varying envelope approximation and the rotating-wave approximation.4,4′-bis(dimethylamino) stilbene organic molecule is one type of one-dimensional symmetrical system and its electronic structure and parameters are calculated by density functional theory.The molecule can be simplified as a three-level system.By numerically simulating the propagation of two-color 2π ultrashort laser pulses in a cascade three-level organic molecule system,we analyze the temporal-spatial evolution properties of the ultrashort laser pulses and the population of each energy level under different resonant conditions.
We study the interaction between the ultra-short laser pulses and the one-dimensional symmetrical π conjugated molecular material (4,4′-bis (dimethylamino) stilbene) by solving Maxwell-Bloch equations. This kind of molecular material has strong nonlinear optical properties, and its electronic structures and dipole moments are calculated by use of density functional theory on ab initio level. The numerical results show that the slowly varying envelope approximation and the rotating wave approximation cannot accurately describe the propagation properties of the ultra-short pulse in the molecular medium. In the case of single photon resonance, the two-level model can well describe the interaction between the small area pulse and the molecular system. For large area pulse, due to the existence of strongly secondary excitation to the higher-lying levels, the three-level model should be used. When the amplitude of the incident electric field is kept constant, the third level's population increases with the increase of the pulse area.
Propagation of strong femtosecond hyper-Gaussian pulses in a cascade three-level molecular system is studied by solving numerically the Maxwell–Bloch equations by the iterative predictor-corrector finite-difference time-domain method. Optical power limiting behavior induced by strong nonlinear two-photon absorption is observed for different orders of the femtosecond hyper-Gaussian pulses. Pulses of a higher order temporal profile are found to have a wider power range of optical limiting but a larger output saturation intensity. Both the output saturation value and the damage threshold of optical power limiting decrease with pulse duration increasing. The decrease of the pulse area along the pulse propagation is much slower than that obtained from the two-photon area theorem due to invalidity of the slowly varying amplitude approximation and the monochromatic field hypothesis.
The Maxwell–Schrödinger equations describing the ultrashort laser pulse propagation in multilevel molecular media are shown to be analytically solvable and to reduce to nonlinear multisine-Gordon equations for certain models of the field–molecule system. Special cases of level schemes are shown to lead to soliton propagation. A numerical study is presented in order to examine the effect of nonresonant (virtual) transitions on pulse propagation and amplification in a three-level molecular system as a function of intensity and detuning.
The time evolution of the cascade omission from an assembly of the three-level atoms excited by two-photon process is investigated under a linear approximation. The propagation effect and the stochastic nature of the quantum noise are fully taken into account. It is found that the time evolution of the emitted radiation shows different behaviors in the three time stages: In the earliest stage a negative feedback mechanism due to the two-photon coherence is important, and the emitted radiation exhibits a characteristic growing behavior peculiar to the cascade system; in the intermediate one this mechanism is destroyed by the dephasing, and a superradiant growth begins; and finally in the latest one this growth is suppressed by the dephasing of the active polarization, and a stationary radiation appears.