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

Optics Letters

Coherent coupling effects in pump–probe measurements with collinear, copropagating beams

Tony F. Heinz, Kenneth B. Eisenthal, Stephen L. Palfrey

Published Aug 1, 1984• 58 citations
Publisher

Abstract

We demonstrate the existence of coherent coupling effects in pump-probe measurements with collinear, copropagating beams, despite the absence of any induced spatial gratings in this geometry. The coherent interaction, which is found to be similar but not identical to that for crossed beams, must be taken into account in analyzing relaxation processes occurring on the time scale of the laser pulse. These coherent effects cannot generally be eliminated by detecting the total change in energy in both the pump and probe beams.

DOI
10.1364/ol.9.000359

Related papers

An Analysis of Coherence Effects in Pump-Probe Measurements

Stephen L. Palfrey, Tony F. Heinz, Kenneth B. Eisenthal

When pump-probe measurements are performed using pulses originating from the same laser, it is necessary to consider the coherent interaction between the two pulses in determining any material relaxation rates on the time scale of the laser pulse.1-5 For pump and probe beams crossing at an angle, the source of the coherent artifact can be understood in the following manner.1 When the two beams are simultaneously present in the sample, they interfere to produce a spatial modulation of the dielectric constant. Light from the pump beam then scatters from this induced grating into the probe direction. This model has led to the suggestion that for the collinear, copropagating beams, where the spatial grating disappears, the coherent artifact should vanish.3 While the spatial modulation is eliminated by choosing this geometry, we demonstrate here that the coherent artifact, which results directly from the nonlinear polarizability of the material, still remains. We have, however, been able to develop a general method for isolating the incoherent response, thus permitting the material relaxation to be extracted without any knowledge of the coherence properties of the pulse.

International Conference on Ultrafast Phenomena•Jan 1, 1984•0 citations

Coherent interactions in pump–probe absorption measurements: the effect of phase gratings

Stephen L. Palfrey, Tony F. Heinz

We show that in order to describe completely the coherent coupling between the pump and probe pulses in a pump– probe measurement of transient absorption, the influence of induced phase gratings must be included. The importance of phase gratings is demonstrated experimentally for the case of a bleachable dye and analyzed in terms of transient four-wave mixing. These results are relevant to the interpretation of pump–probe measurements on all time scales performed with pulses from a single laser, particularly when the pulse duration is comparable with the material response time.

Journal of the Optical Society of America B•Apr 1, 1985•106 citations

Contribution of phase gratings in pump- probe measurements of induced absorption

Tony F. Heinz, Stephen L. Palfrey

In pump-probe experiments, the coherent interaction between the pump and probe pulses must be taken into account when determining response times comparable with pulse duration. Previously, only the contribution to the coupling arising from the induced amplitude grating in the sample has been considered.1–4 We show here that contributions resulting from a phase grating must also in general be Included.5

Conference on Lasers and Electro-Optics•Jan 1, 1985•0 citations

Coherent phenomena involved in the time-resolved optical Kerr effect

J. L. Oudar

The effect of parametric coupling between pump and probe beams in time-resolved optical Kerr effect is theoretically discussed for various experimental configurations. It is shown that with a cicularly polarized pump beam, the polarization changes induced on a nearly collinear probe beam are due to this coherence effect only. In other configurations, this parametric coupling can appear as an additional contribution to the observed signal, especially when pump and probe are derived from the same laser beam. It is pointed out that this coupling can occur not only when the pump and probe beams are at the same wavelength, but also when the difference or the sum of their frequencies can excite a Raman or a two-photon resonance in the medium.

IEEE Journal of Quantum Electronics•Apr 1, 1983•47 citations

Coherent interaction effects in probe pulse experiments

B. Wilhelmi, Joachım Herrmann

An investigation is made of resonance absorption of picosecond pulses when time-delayed approximately collinear or exactly counterpropagating pump and probe pulses are superposed in a sample. The coherent and incoherent components of the influence of the probe beam on the absorption are calculated as a function of the delay time. In addition, the influence of phase modulation of the pump wave and emission of waves of different diffraction orders is studied.

Soviet Journal of Quantum Electronics•Sep 30, 1980•9 citations

Coherent interaction of laser pulses in a resonant optically dense extended medium under the regime of strong field-matter coupling

V. S. Egorov, Victor Lebedev, Igor B. Mekhov +3 more

The nonstationary pump-probe interaction between short laser pulses propagating in a resonant optically dense coherent medium is considered. Special attention is paid to the case where the density of two-level particles is high enough that a considerable part of the energy of relatively weak external laser fields can be coherently absorbed and reemitted by the medium. Thus, the field of the medium reaction plays a key role in the interaction processes, which leads to collective behavior of an atomic ensemble in the strongly coupled light-matter system. Such behavior results in fast excitation interchanges between the field and a medium in the form of optical ringing, which is analogous to polariton beating in solid-state optics. This collective oscillating response, which can be treated as successive beats between light wave packets of different group velocities, is shown to significantly affect the propagation and amplification of the probe field under its nonlinear interaction with a nearly copropagating pump pulse. Depending on the probe-pump time delay, the probe transmission spectra show the appearance of either a specific doublet or coherent dip. The widths of these features are determined by the density-dependent field-matter coupling coefficient and increase during the propagation. Besides that, the widths of the coherent features, which appear close to resonance in the broadband probe spectrum, exceed the absorption-line width, since under the strong-coupling regime, the frequency of optical ringing exceeds the rate of incoherent relaxation. Contrary to stationary strong-field effects, the density- and coordinate-dependent transmission spectra of the probe manifest the importance of collective oscillations and cannot be obtained in the framework of a single-atom model.

arXiv:quant-ph/0308155•Physical Review A•Mar 3, 2004•16 citations
We demonstrate the existence of coherent coupling effects in pump-probe measurements with collinear, copropagating beams, despite the absence of any induced spatial gratings in this geometry. The coherent interaction, which is found to be similar but not identical to that for crossed beams, must be taken into account in analyzing relaxation processes occurring on the time scale of the laser pulse. These coherent effects cannot generally be eliminated by detecting the total change in energy in both the pump and probe beams.
When pump-probe measurements are performed using pulses originating from the same laser, it is necessary to consider the coherent interaction between the two pulses in determining any material relaxation rates on the time scale of the laser pulse.1-5 For pump and probe beams crossing at an angle, the source of the coherent artifact can be understood in the following manner.1 When the two beams are simultaneously present in the sample, they interfere to produce a spatial modulation of the dielectric constant. Light from the pump beam then scatters from this induced grating into the probe direction. This model has led to the suggestion that for the collinear, copropagating beams, where the spatial grating disappears, the coherent artifact should vanish.3 While the spatial modulation is eliminated by choosing this geometry, we demonstrate here that the coherent artifact, which results directly from the nonlinear polarizability of the material, still remains. We have, however, been able to develop a general method for isolating the incoherent response, thus permitting the material relaxation to be extracted without any knowledge of the coherence properties of the pulse.
We show that in order to describe completely the coherent coupling between the pump and probe pulses in a pump– probe measurement of transient absorption, the influence of induced phase gratings must be included. The importance of phase gratings is demonstrated experimentally for the case of a bleachable dye and analyzed in terms of transient four-wave mixing. These results are relevant to the interpretation of pump–probe measurements on all time scales performed with pulses from a single laser, particularly when the pulse duration is comparable with the material response time.
The effect of parametric coupling between pump and probe beams in time-resolved optical Kerr effect is theoretically discussed for various experimental configurations. It is shown that with a cicularly polarized pump beam, the polarization changes induced on a nearly collinear probe beam are due to this coherence effect only. In other configurations, this parametric coupling can appear as an additional contribution to the observed signal, especially when pump and probe are derived from the same laser beam. It is pointed out that this coupling can occur not only when the pump and probe beams are at the same wavelength, but also when the difference or the sum of their frequencies can excite a Raman or a two-photon resonance in the medium.
The nonstationary pump-probe interaction between short laser pulses propagating in a resonant optically dense coherent medium is considered. Special attention is paid to the case where the density of two-level particles is high enough that a considerable part of the energy of relatively weak external laser fields can be coherently absorbed and reemitted by the medium. Thus, the field of the medium reaction plays a key role in the interaction processes, which leads to collective behavior of an atomic ensemble in the strongly coupled light-matter system. Such behavior results in fast excitation interchanges between the field and a medium in the form of optical ringing, which is analogous to polariton beating in solid-state optics. This collective oscillating response, which can be treated as successive beats between light wave packets of different group velocities, is shown to significantly affect the propagation and amplification of the probe field under its nonlinear interaction with a nearly copropagating pump pulse. Depending on the probe-pump time delay, the probe transmission spectra show the appearance of either a specific doublet or coherent dip. The widths of these features are determined by the density-dependent field-matter coupling coefficient and increase during the propagation. Besides that, the widths of the coherent features, which appear close to resonance in the broadband probe spectrum, exceed the absorption-line width, since under the strong-coupling regime, the frequency of optical ringing exceeds the rate of incoherent relaxation. Contrary to stationary strong-field effects, the density- and coordinate-dependent transmission spectra of the probe manifest the importance of collective oscillations and cannot be obtained in the framework of a single-atom model.