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

Journal of Experimental and Theoretical Physics Letters

Femtosecond dephasing of coherent excitation and ultrafast switching of resonant optical nonlinearity of molecular aggregates

Anatolii A. Ivanov, Mikhail V. Alfimov, Aleksei M. Zheltikov

Published Jul 1, 2006• 0 citations
Publisher

Abstract

One-and two-photon-resonant nonlinear-optical interactions of ultrashort laser pulses are employed to measure the dephasing time of coherent excitation and to investigate the ultrafast population dynamics of molecular aggregates. Dephasing of coherent excitation of molecular aggregates with a characteristic phase relaxation time of about 120 fs is visualized. Ultrafast switching of optical nonlinearity in molecular aggregates with a typical switching time of about 450 fs is demonstrated.

DOI
10.1134/s0021364006100043

Related papers

Dephasing of Excitonic Transition of J-Aggregates Measured by Time-resolved Resonance CARS

V. F. Kamaloyl, Ryoji Inaba, Keitaro Yoshihara

J-aggregates are the subject of great interest due to high values of optical susceptibilities of intensive excitonic resonance, originated from delocalization of electronic excitation in molecular aggregate. In [1,2] resonant enhancement of third-order susceptibiltity of J-aggregates of pseudoisocyanine (PIC) solutions was observed. The dephasing time of excitonic transition of PIC J-aggregate solutions was determined in [3] as 16 ps by low-temperature photon echo, and T2=0.17 ps at room temperature by measuring the dispersion of nonlinear susceptibility in the process of four-wave mixing [2].

International Conference on Ultrafast Phenomena•Jan 1, 1992•0 citations

Measurement of coherent polarisation relaxation times in condensed media using femtosecond interferometric spectroscopy

V. O. Kompanets, Yu. A. Matveets, Sergey V. Chekalin

An ultrafast spectrometer with a temporal resolution of 20 fs for studying the polarisation wave interference in condensed matter upon resonance excitation by femtosecond laser pulses is described. The transverse relaxation times T 2 < 20 and 50 fs are measured in optical media with considerably different inhomogeneous broadenings.

Quantum Electronics•May 31, 2001•0 citations

Coherent Transients by Optical Phase Switching: Dephasing in La Cl3 : Pr3+

Azriel Z. Genack, David A. Weitz, R. M. Macfarlane +2 more

A novel coherent transient effect is observed following a rapid shift in the relative phase of an exciting laser and sample polarization. An analytical expression is derived for the signal which is a sum of exponentially decaying terms with characteristic times involving both ${T}_{1}$ and ${T}_{2}$. Phase switching is a powerful approach to the study of optical relaxation and is applied here to measure dephasing in La${\mathrm{Cl}}_{3}$: ${\mathrm{Pr}}^{3+}$.

Physical Review Letters•Aug 11, 1980•31 citations

Quantum control of optical four-wave mixing with femtosecond !-3! laser pulses: coherent ac Stark nonlinear spectroscopy

Carles Serrat

The four-wave mixing produced with two ultrashort phase-locked !-3! laser pulses propagating coherently in a two-level system in the infrared spectral region is shown to depend on the pulses relative phase. The Maxwell-Bloch equations are solved beyond the rotating-wave approximation to account for field frequencies which are largely detuned from the atomic resonance. The relative phase dominating the efficiency of the coupling to the 5! anti-Stokes Raman component is determined by sign of the total ac Stark shift induced in the system, in such a way that the phase influence disappears precisely where the ac Stark effect due to both pulses is compensated. This fundamental quantum interference effect can be the basis for nonlinear ultrafast optical spectroscopy techniques. Phenomena arising from the coherent control of nonlinear interactions are of importance in fields as diverse as optoelectronics and materials research, in high harmonic generation, in photoionization or molecular dissociation, and in biological applications such as spectroscopy and imaging, among others [1, 2, 3, 4, 5, 6, 7]. Optical quantum coherent control is based on the fact that the phases of interfering transition amplitudes in light-matter interactions can be controlled through the optical phase of coherent light sources that drive the interaction, in such a way that the transition rates to final states and the dynamics at various stages of the process can be modified [1]. In a recent paper [8], a theoretical investigation on the quantum coherent control of the optical transient four-wave mixing of two intense phase-locked femtosecond laser pulses of central angular frequencies ω and 3ω propagating in a two-level atom (TLA) was reported. It was shown how the nonlinear (χ (3) ) coupling to the antiStokes Raman field at frequency 5ω depends critically on the initial relative phase φ of the propagating pulses. In Ref. [8], the study was centered to intense pulses in the visible and ultraviolet spectral regions, with frequencies at resonance or lower than the atomic transition. The phenomena observed in [8], however, can be scaled to various laser and material parameters. In the infrared spectral range, for instance, experiments on ultrafast molecular dynamics are frequently performed by help of twocolor pump probe nonlinear spectroscopy techniques. In this type of studies, due to the high intensities inherent to ultrashort (subpicosecond) pulses, nonlinear effects such as stimulated Raman processes may become important and are often utilized as a complementary tool to gain information [9]. In this Letter, we address the conditions for quantum coherent control of transient four-wave mixing interactions with two phase-locked ω-3ω femtosecond laser pulses in the mid-IR spectral region. Our purpose is to reveal the basic physics for a strict two-level medium and to this end the Maxwell-Bloch TLA will be considered. We will study pulses with a duration of 300 fs (with a w 5w

•Jan 1, 2008•0 citations

Nonlinear Optical Processes With Incoherent Light And Their Applications For Studies Of Ultrafast Dephasing

Peixian Ye

In recent years, a series of nonlinear optical processes with incoherent light, such as time-delay four-wave mixing, optical Kerr effect and coherent Stokes Raman scattering, were developed and attracted much attention. It has been demonstrated that these processes can be used to measure the ultrafast dephasing times of excitations (shorter than 1 psec.) with nanosecond pulse lasers or even CW lasers. In this talk, after a short review of the works done by others previously theoretical and experimental investigations in this field in my laboratory are presented.

Digest on Nonlinear Optics: Materials, Phenomena and Devices•Jan 1, 1990•0 citations

Direct Observation of Coherent Medium Response under the Condition of Two-Photon Excitation of Krypton by Femtosecond UV-Laser Pulses

Olaf Kittelmann, Jens Ringling, A. Nazarkin +2 more

Coherent Rabi oscillations and subsequent phase relaxation of excitation were observed under the condition of two-photon resonant interaction of Kr atoms with intense femtosecond 193 nm laser pulses. The coherent dynamics of the atomic transition exposed to an intense field was resolved using the technique of fs-pulse four-wave mixing with probe pulses significantly shorter than the pump pulses.

Physical Review Letters•Apr 8, 1996•27 citations
One-and two-photon-resonant nonlinear-optical interactions of ultrashort laser pulses are employed to measure the dephasing time of coherent excitation and to investigate the ultrafast population dynamics of molecular aggregates. Dephasing of coherent excitation of molecular aggregates with a characteristic phase relaxation time of about 120 fs is visualized. Ultrafast switching of optical nonlinearity in molecular aggregates with a typical switching time of about 450 fs is demonstrated.
J-aggregates are the subject of great interest due to high values of optical susceptibilities of intensive excitonic resonance, originated from delocalization of electronic excitation in molecular aggregate. In [1,2] resonant enhancement of third-order susceptibiltity of J-aggregates of pseudoisocyanine (PIC) solutions was observed. The dephasing time of excitonic transition of PIC J-aggregate solutions was determined in [3] as 16 ps by low-temperature photon echo, and T2=0.17 ps at room temperature by measuring the dispersion of nonlinear susceptibility in the process of four-wave mixing [2].
A novel coherent transient effect is observed following a rapid shift in the relative phase of an exciting laser and sample polarization. An analytical expression is derived for the signal which is a sum of exponentially decaying terms with characteristic times involving both T1{T}_{1}T1​ and T2{T}_{2}T2​. Phase switching is a powerful approach to the study of optical relaxation and is applied here to measure dephasing in LaCl3{\mathrm{Cl}}_{3}Cl3​: Pr3+{\mathrm{Pr}}^{3+}Pr3+.
The four-wave mixing produced with two ultrashort phase-locked !-3! laser pulses propagating coherently in a two-level system in the infrared spectral region is shown to depend on the pulses relative phase. The Maxwell-Bloch equations are solved beyond the rotating-wave approximation to account for field frequencies which are largely detuned from the atomic resonance. The relative phase dominating the efficiency of the coupling to the 5! anti-Stokes Raman component is determined by sign of the total ac Stark shift induced in the system, in such a way that the phase influence disappears precisely where the ac Stark effect due to both pulses is compensated. This fundamental quantum interference effect can be the basis for nonlinear ultrafast optical spectroscopy techniques. Phenomena arising from the coherent control of nonlinear interactions are of importance in fields as diverse as optoelectronics and materials research, in high harmonic generation, in photoionization or molecular dissociation, and in biological applications such as spectroscopy and imaging, among others [1, 2, 3, 4, 5, 6, 7]. Optical quantum coherent control is based on the fact that the phases of interfering transition amplitudes in light-matter interactions can be controlled through the optical phase of coherent light sources that drive the interaction, in such a way that the transition rates to final states and the dynamics at various stages of the process can be modified [1]. In a recent paper [8], a theoretical investigation on the quantum coherent control of the optical transient four-wave mixing of two intense phase-locked femtosecond laser pulses of central angular frequencies ω and 3ω propagating in a two-level atom (TLA) was reported. It was shown how the nonlinear (χ (3) ) coupling to the antiStokes Raman field at frequency 5ω depends critically on the initial relative phase φ of the propagating pulses. In Ref. [8], the study was centered to intense pulses in the visible and ultraviolet spectral regions, with frequencies at resonance or lower than the atomic transition. The phenomena observed in [8], however, can be scaled to various laser and material parameters. In the infrared spectral range, for instance, experiments on ultrafast molecular dynamics are frequently performed by help of twocolor pump probe nonlinear spectroscopy techniques. In this type of studies, due to the high intensities inherent to ultrashort (subpicosecond) pulses, nonlinear effects such as stimulated Raman processes may become important and are often utilized as a complementary tool to gain information [9]. In this Letter, we address the conditions for quantum coherent control of transient four-wave mixing interactions with two phase-locked ω-3ω femtosecond laser pulses in the mid-IR spectral region. Our purpose is to reveal the basic physics for a strict two-level medium and to this end the Maxwell-Bloch TLA will be considered. We will study pulses with a duration of 300 fs (with a w 5w
In recent years, a series of nonlinear optical processes with incoherent light, such as time-delay four-wave mixing, optical Kerr effect and coherent Stokes Raman scattering, were developed and attracted much attention. It has been demonstrated that these processes can be used to measure the ultrafast dephasing times of excitations (shorter than 1 psec.) with nanosecond pulse lasers or even CW lasers. In this talk, after a short review of the works done by others previously theoretical and experimental investigations in this field in my laboratory are presented.