Phase-dependent absorption and stimulated emission in femtosecond pump-probe experiments

Fain, Benjamin; Lin, Su

doi:10.1016/0009-2614(93)89002-y

Cited by 17 publications

(13 citation statements)

References 24 publications

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“…Linear response theory of four-wave mixing typically represents the separate moments from cumulant expansions of the density operator, as shown by several authors in the past [46,[49][50][51][52]. A very useful picture of the interaction caused by the pump pulse, when separated from a probe, represents the 'Wigner' phase space [53][54][55] which allows a semi-classical description of the ultrafast material response.…”

Section: Vibrational Coherence Contributions With Femtosecond Opticalmentioning

confidence: 99%

Populations and coherence in femtosecond time resolved X-ray crystallography of the photoactive yellow protein

Hutchison

Thor

2017

International Reviews in Physical Chemistry

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Ultrafast X-ray crystallography of the Photoactive Yellow Protein with femtosecond delays using an X-ray Free Electron Laser has successfully probed the dynamics of an early FranckCondon species. The femtosecond pump-probe application of protein crystallography represents a new experimental regime that provides an X-ray structural probe for coherent processes that were previously accessible primarily using ultrafast spectroscopy. We address how the optical regime of the visible pump, that is necessary to successfully resolve ultrafast structural differences, affects the motions that are measured using the technique. The subpicosecond photochemical dynamics in PYP involves evolution of a mixture of electronic ground and excited state populations. Additionally, within the dephasing time structural motion include vibrational coherence arising from excited states, the ground state and a ground state intermediate under experimental conditions used for ultrafast crystallography. Intense optical pulses are required to convert population levels in PYP crystals that allow detection by X-ray crystallography, but the compromise currently needed for the optical bandwidth and power has consequences with regard to the contributions to the motions that are experimentally measured with femtosecond delays. We briefly review the ultrafast spectroscopy literature of the primary photoreactions of PYP and discuss relevant physical models taken from coherent control and femtosecond coherence spectroscopy literature that address both the population transfer as well 2 as the vibrational coherences. We apply linear response theory, with the additional use of a high power approximation, of on-resonance impulsive vibrational coherence in the ground state and the non-impulsive coherence in the excited state and discuss experimental approaches to manipulate the coherence contributions. The results are generalised and extended to discuss the future capabilities of high repetition rate XFEL instruments providing enhanced sensitivity to perform the crystallographic equivalent of an impulsive Raman measurement of vibrational coherence.

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Section: Vibrational Coherence Contributions With Femtosecond Opticalmentioning

confidence: 99%

Populations and coherence in femtosecond time resolved X-ray crystallography of the photoactive yellow protein

Hutchison

Thor

2017

International Reviews in Physical Chemistry

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“…[28][29][30] Another approach in the well-separated pulse limit is based on a description of the pump induced medium using nonstationary effective linear response functions. 10,25,[31][32][33] We have recently demonstrated the application of an effective linear response approach to pump-probe spectroscopy using a displaced thermal state representation of the pump induced ͑doorway͒ density matrix. 27 A key requirement for this representation is a knowledge of the moments of position (Q) and momentum ( P) in the doorway state.…”

Section: Introductionmentioning

confidence: 99%

Investigations of ultrafast nuclear response induced by resonant and nonresonant laser pulses

Kumar¹,

Rosca²,

Widom³

et al. 2001

The Journal of Chemical Physics

103

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We analyze the nonstationary vibrational states prepared by ultrashort laser pulses interacting with a two electronic level molecular system. Fully quantum mechanical expressions are derived for all the moments of the coordinate and momentum operators for the vibrational density matrices associated with the ground and excited electronic states. The analysis presented here provides key information concerning the temperature and carrier frequency dependence of the moments, and relates the moments to equilibrium absorption and dispersion line shapes in a manner analogous to the ''transform methods'' previously used to describe resonance Raman scattering. Particular attention is focused on the first two moments, for which simple analytical expressions are obtained that are computationally easy to implement. The behavior of the first two moments with respect to various parameters such as the pulse carrier ͑center͒ frequency, pulse width, mode frequency, electron-nuclear coupling strength, and temperature is investigated in detail. Using rigorous analytical formulas, we also discuss the laser pulse induced squeezing of the nuclear distributions as well as the pulse induced vibrational heating/cooling in the ground and excited states. The moment analysis of the pump induced state presented here offers a convenient starting point for the analysis of signals measured in pump-probe spectroscopy. The moment analysis can also be used, in general, to better understand the material response following ultrashort laser pulse excitation.

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“…The absorption spectrum at a frequency ⍀ is given by 34 are the Fourier transforms of the positive frequency components of the polarization P ϩ (t) and the field amplitude E(t), respectively. An optical polarization in the medium P(t) ϭ P ϩ (t)exp(Ϫit)ϩc.c.…”

Section: Calculation Of the Absorption Spectrummentioning

confidence: 99%

“…͑33͒ shows a phase dependent absorption. 34 In spite of the presence of a relatively large parameter in the denominator of this term, the last can be important when the imaginary part of the susceptibility Im ͓(t sp ),t sp ͔ϳ͐ Ϫϱ ϱ d␣͓F 1M ((t sp )Ϫ 21 ϩ␣) 1s (␣,t sp )ϪF 2M ((t sp )Ϫ 21 ϩ␣) 2s (␣,t sp )] is small. At the same time the real part of the susceptibility Re ((t),t) does not need to be small due to different frequency dependences of the imaginary and real parts of the susceptibility.…”

Section: ͑29͒mentioning

confidence: 99%

“…Really, in the nonstationary media the absorption depends on the electric field phase. 34 Correspondingly, the absorption spectrum depends on both the real and imaginary part of the susceptibility. In contrast, in the stationary media the absorption is conventionally proportional to the imaginary part of the susceptibility and depends on the population difference of molecular levels.…”

Section: Introductionmentioning

confidence: 99%

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Chirped pulse excitation in condensed phases involving intramolecular modes. II. Absorption spectrum

Fainberg

Narbaev

2002

The Journal of Chemical Physics

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Articles you may be interested inDynamics of the time-resolved stimulated Raman scattering spectrum in presence of transient vibronic inversion of population on the example of optically excited trans-β-apo-8′-carotenal Experimental investigation of the Jahn-Teller effect in the ground and excited electronic states of the tropyl radical. Part II. Vibrational analysis of the A ̃ E 3 ″ 2 -X ̃ E 2 ″ 2 electronic transitionWe have calculated the absorption spectrum of an intense chirped pulse exciting a solute molecule in a solvent. The excitation of quantum intramolecular modes has been also taken into account. In general absorption depends on both the real and imaginary part of the susceptibility ͑a phase-dependent absorption in the nonstationary media͒. We have shown that for strongly chirped pulses, the absorption spectrum can be expressed by the difference of the convolutions of the ''intramolecular'' absorption and luminescence spectra with the instantaneous population wave packets in the ground and excited electronic states, respectively. Incorporating of optically active high-frequency intramolecular vibrational modes eliminates the qualitative discrepancies between experimental and calculated absorption spectra which occurred in the model of one vibronic transition.

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Phase-dependent absorption and stimulated emission in femtosecond pump-probe experiments

Cited by 17 publications

References 24 publications

Populations and coherence in femtosecond time resolved X-ray crystallography of the photoactive yellow protein

Populations and coherence in femtosecond time resolved X-ray crystallography of the photoactive yellow protein

Investigations of ultrafast nuclear response induced by resonant and nonresonant laser pulses

Chirped pulse excitation in condensed phases involving intramolecular modes. II. Absorption spectrum

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