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

The Journal of Chemical Physics

Molecular multiphoton excitation by phase coherent pulse pairs

Sylvette Besnaïnou, J.-C. Diels, James P. Stone

Published Jul 1, 1984• 14 citations
Publisher

Abstract

We theoretically analyze the absorption of media excited by a pair of coherent pulses, as a function of their relative phase, in conditions of multiphoton resonance and negligible dephasing. It is shown that, the periodicity of transmission vs delay and phase, is characteristic of the nature and order of the process. Also a multilevel system may evolve from pure multiphoton resonance to cascade resonance under specific conditions depending on the detunings of the levels involved.

DOI
10.1063/1.447377

Related papers

Coherent Multiphoton Resonant Interaction And Harmonic Generation

Arindum Mukherjee, Nandini Mukherjee, Grigory Arzumanyan +1 more

As a succession of two pulses propagates through a medium which exhibits a resonance (single or multiphoton), the resonant parts of the susceptibility will depend on the relative phase of the two pulses, provided the delay between the pulses is shorter than the phase relaxation time of the interaction. As a result of this "coherent interaction", the reradiation of the sample (the fluorescence, the absorption and the generation of harmonics) will be a periodic function of the phase difference and delay between the two pulses of the sequence 1. The study of these coherent effects is important, because one expect to find conditions under which the maximum harmonic conversion to much shorter wavelengths can be greatly enhanced 2. The presence of the multiphoton resonance enhances the nonlinear susceptibility responsible for the harmonic generation, but reduces also the maximum achievable conversion efficiency because of resonant losses (depletion of the fundamental by multiphoton absorption). The latter effect can be eliminated by a judicious choice of the pulse sequencing and phasing. In addition to demonstrating, for the first time, coherent interaction enhancement in harmonic generation, the data of third harmonic versus relative phase of the pulse sequences enable us to measure the phase angle of the third order susceptibility (hence the contribution of the continuum relative to that of the resonance).

International Conference on Ultrafast Phenomena•Jan 1, 1986•0 citations

Coherent multiphoton absorption: Dependency on the relative phase of two successive pulses

Sylvette Besnaïnou, James P. Stone, Jean‐Claude Diels

Abstract When a multilevel system excited by a laser pulse absorbs a cascade of photons, a second pulse of same frequency, equal duration but dephased by π takes it back to its initial state. This property can be inferred by studying the laser field system interaction matrix, using the rotating wave approximation.

International Journal of Quantum Chemistry•Nov 1, 1982•3 citations

Multiphoton coherent excitation of molecules

J.-C. Diels, Sylvette Besnaïnou

Two different approaches to multiphoton excitation of an anharmonic multilevel system are presented. Both methods result in nearly complete population of the upper state. The first approach involving phase shifting portions of the coherent excitation is treated analytically with square pulses. The second approach uses sequences of several pulses with selected relative phase and delays. Some numerical examples are presented for three- and four-photon excitation of the vibrational level structure of CH3F. This particular molecule is again taken as model to demonstrate four-photon excitation with a five pulse sequence, taking into account the rotational line structure. The rotational line distribution in the upper state is seen to correspond to a lower temperature than in the ground state.

The Journal of Chemical Physics•Dec 1, 1986•51 citations

Peculiarities of dynamics of molecular multilevel systems in a powerful laser field: anaytical solutions

В. А. Савва, V. I. Zelenkov, O. V. Khlus

Analytical solutions of the equations describing coherent dynamics of various multilevel systems excited by radiation are given. The peculiarities of dynamics related with detuning from resonance, with arrangement and amount of levels, with dipole moment dependence on level number, along with excitation in a pulse laser field are studied.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•May 31, 2002•0 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

Coherent phase control of resonance-mediated (2+1) three-photon absorption

Andrey Gandman, Lev Chuntonov, Leonid Rybak +1 more

Femtosecond coherent phase control of resonance mediated $(2+1)$ three-photon absorption is studied both theoretically and experimentally. The regime is perturbative of third order. The photoexcitation coherently combines elements of both nonresonant and resonance-mediated multiphoton transitions. By proper simple pulse shaping the three-photon absorption in Na is effectively controlled experimentally, enhanced up to $\ensuremath{\sim}300%$ of the absorption induced by the transform-limited pulse. It is achieved by phase manipulating intra- and intergroup interferences involving two groups of three-photon excitation pathways: (i) on resonance and (ii) near resonance with the intermediate resonance state accessed by nonresonant two-photon transition.

Physical Review A•Mar 9, 2007•70 citations
We theoretically analyze the absorption of media excited by a pair of coherent pulses, as a function of their relative phase, in conditions of multiphoton resonance and negligible dephasing. It is shown that, the periodicity of transmission vs delay and phase, is characteristic of the nature and order of the process. Also a multilevel system may evolve from pure multiphoton resonance to cascade resonance under specific conditions depending on the detunings of the levels involved.
As a succession of two pulses propagates through a medium which exhibits a resonance (single or multiphoton), the resonant parts of the susceptibility will depend on the relative phase of the two pulses, provided the delay between the pulses is shorter than the phase relaxation time of the interaction. As a result of this "coherent interaction", the reradiation of the sample (the fluorescence, the absorption and the generation of harmonics) will be a periodic function of the phase difference and delay between the two pulses of the sequence 1. The study of these coherent effects is important, because one expect to find conditions under which the maximum harmonic conversion to much shorter wavelengths can be greatly enhanced 2. The presence of the multiphoton resonance enhances the nonlinear susceptibility responsible for the harmonic generation, but reduces also the maximum achievable conversion efficiency because of resonant losses (depletion of the fundamental by multiphoton absorption). The latter effect can be eliminated by a judicious choice of the pulse sequencing and phasing. In addition to demonstrating, for the first time, coherent interaction enhancement in harmonic generation, the data of third harmonic versus relative phase of the pulse sequences enable us to measure the phase angle of the third order susceptibility (hence the contribution of the continuum relative to that of the resonance).
Two different approaches to multiphoton excitation of an anharmonic multilevel system are presented. Both methods result in nearly complete population of the upper state. The first approach involving phase shifting portions of the coherent excitation is treated analytically with square pulses. The second approach uses sequences of several pulses with selected relative phase and delays. Some numerical examples are presented for three- and four-photon excitation of the vibrational level structure of CH3F. This particular molecule is again taken as model to demonstrate four-photon excitation with a five pulse sequence, taking into account the rotational line structure. The rotational line distribution in the upper state is seen to correspond to a lower temperature than in the ground state.
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.
Femtosecond coherent phase control of resonance mediated (2+1)(2+1)(2+1) three-photon absorption is studied both theoretically and experimentally. The regime is perturbative of third order. The photoexcitation coherently combines elements of both nonresonant and resonance-mediated multiphoton transitions. By proper simple pulse shaping the three-photon absorption in Na is effectively controlled experimentally, enhanced up to $\ensuremath{\sim}300%$ of the absorption induced by the transform-limited pulse. It is achieved by phase manipulating intra- and intergroup interferences involving two groups of three-photon excitation pathways: (i) on resonance and (ii) near resonance with the intermediate resonance state accessed by nonresonant two-photon transition.