Spectrally resolved fs-CARS as a probe of the vibrational dynamics of a large polyatomic molecule: magnesium octaethylporphyrin

Heid, M.; Chen, T.; Schmitt, Ulrich; Kiefer, W.

doi:10.1016/s0009-2614(00)01456-1

Cited by 32 publications

(18 citation statements)

References 28 publications

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“…During the past two decades, numerous investigations on vibrational dynamics have been made on a variety of systems using Raman spectroscopy as well as time-resolved techniques [1][2][3][4][5][6][7]. Recent advances [8] in ultrafast spectroscopy have opened up several possibilities to probe hitherto unexplored aspects of coherent vibrational dynamics in condensed phase [3-7, 9, 10].…”

Section: Introductionmentioning

confidence: 99%

Vibrational Dynamics in Hydrogen-Bonded (Pyridine + Water) Complexes Studied by Spectrally Resolved Femtosecond CARS

Schlücker¹,

Heid²,

Singh³

et al. 2002

Zeitschrift Für Physikalische Chemie

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Vibrational Dynamics / Femtosecond CARS / Hydrogen-Bonded ComplexesThe technique of femtosecond time-resolved coherent anti-Stokes Raman spectroscopy (fs-CARS) was used to study the vibrational dephasing dynamics in hydrogen-bonded (pyridine + water) complexes as a function of pyridine mole fraction x(Py). By detecting the spectrally resolved CARS signal, a mapping of the vibrational coherence dynamics of ring modes at ≈ 990 and ≈ 1030 cm −1 was achieved. The quantum beatings among different modes of the hydrogen-bonded network are clearly exhibited in the transient signal. Its spectral analysis yields the involved frequencies by employing FT methods to the time domain signal. The oscillatory pattern in the CARS transients are adequately explained when contributions from several modes are accounted for. The individual vibrational dephasing times (T 2 ) in the range ≈ 1.7-5.3 ps were obtained with high precision. The assumption of homogeneous broadening of the ring modes under investigation is made for those mole fractions, where the pyridine molecules have a surrounding consisting mainly of only one species. According to the concentration profile this is valid for x(Py) = 1.00 (neat pyridine) and x(Py) = 0.20, for which the hydrogen-bonded network is dominated by PyW n species (i.e. water-water hydrogen bonding). For both mole fractions the condition (∆ν 1/2 ) hom = 1/πcT 2 , which relates line width in wavenumber from Raman data and dephasing time from time-resolved data, is fulfilled. Inhomogeneous broadening is assumed for the intermediate concentration x(Py) = 0.60 since several distinct species, such as: Py 2 W, PyW, and PyW 2 are known to co-exist leading to complex chemical equilibria.

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Section: Introductionmentioning

confidence: 99%

Vibrational Dynamics in Hydrogen-Bonded (Pyridine + Water) Complexes Studied by Spectrally Resolved Femtosecond CARS

Schlücker¹,

Heid²,

Singh³

et al. 2002

Zeitschrift Für Physikalische Chemie

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“…5) the fields can produce a wave with λ (5ω) = 348.6 nm. The parameter values in this second study have been chosen to be close to those for transitions that are relevant in biological applications, with similar schemes being currently investigated with femtosecond CARS techniques [14,15,16]. The Maxwell-Bloch equations can be written as [8] ∂H…”

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confidence: 99%

Coherent control of ultrafast optical four-wave mixing with two-colorω−3ωlaser pulses

Serrat¹

2005

Phys. Rev. A

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A theoretical investigation on the quantum control of optical coherent four-wave mixing interactions in two-level systems driven by two intense synchronized femtosecond laser pulses of central angular frequencies ω and 3ω is reported. By numerically solving the full Maxwell-Bloch equations beyond the slowly-varying envelope and rotating-wave approximations in the time domain, the nonlinear coupling to the optical field at frequency 5ω is found to depend critically on the initial relative phase φ of the two propagating pulses; the coupling is enhanced when the pulses interfere constructively in the center (φ = 0), while it is nearly suppressed when they are out of phase (φ = π). The tuning of the initial absolute phase of the different frequency components of synchronously propapagating ω-3ω femtosecond pulses can serve as a means to control coherent anti-Stokes Raman (CARS) processes.In recent years, encouraged by the developments in the engineering of intense ultrashort laser fields with a well defined absolute phase [1], studies on the phase control of the interaction of two-color strong ultrashort laser pulses in nonlinear materials have received a great interest [2,3,4,5,6,7]. Phenomena arising from such ultrashort pulse interaction can be of extreme importance in fields as diverse as optoelectronics and materials research, in biological applications such as spectroscopy and microscopy, in high harmonic generation, and in photoionization or molecular dissociation, among others.It is known that when the pulses duration approach the duration of only several optical cycles, theories based on the slowly-varying envelope approximation (SVEA) and the rotating-wave approximation (RWA) are not appropriate, since phenomena such as electric field timederivatives leading to carrier-wave reshaping [8], or the generation of high spectral components [9], can not be described by such theories. In these situations, accurate numerical modeling based on the finite-difference timedomain (FDTD) method [10] is being increasingly used to investigate the full set of optical Maxwell-Bloch equations [7,8,9,11].In this Letter, we investigate the possibility of phase control of transient four-wave mixing interactions in twolevel systems driven by two mutually coherent intense ultrashort pulses of central angular frequencies ω and 3ω. We employ a standard predictor-corrector FDTD numerical approach which incorporates all propagation effects -such as nonlinearity, dispersion, absorption, dissipation, saturation, and other resonance effects- [8], to study the sensitivity on the relative phase φ of the nonlinear coupling of the ω-3ω pulses to the field at frequency 5ω, which results from the interaction of the waves through the third order susceptibility of the medium (χ (3) ) [12].By describing the evolution of the field spectrum as the two-color pulses propagate through the medium, our simulations demonstrate that the generation of the 5ω-component is enhanced when the two pulses are in phase (φ = 0), while it is nearly suppressed when ...

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“…We then make use of a theoretical description of fs-CARS which explicitly implies the relaxation behavior of the excited modes. In this formulation, and for the situation where the pulse durations of the laser pulses is considerably shorter than the dephasing times T 2j , the spectrally dispersed transient signal can be written as 6,7,25 …”

Section: Vibrational Dephasingmentioning

confidence: 99%

“…Very recently we have reported on a fs time-resolved CARS experiment that has been performed on magnesium octatethylporphyrin (MgOEP) dissolved in dichloromethane. 25 In order to overcome the above mentioned difficulty, the coherent antiStokes transient signal has been detected spectrally dispersed resulting in a two-dimensional (time and wavenumber) data…”

Section: Introductionmentioning

confidence: 99%

Two‐dimensional probing of ground‐state vibrational dynamics in porphyrin molecules by fs‐CARS

Heid

Schlücker

Schmitt

et al. 2001

J Raman Spectroscopy

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We report on spectrally dispersed femtosecond time-resolved coherent anti-Stokes Raman scattering (CARS) for the investigation of the electronic ground-state vibrational dynamics of porphyrin molecules in solution. The two-dimensional experimental data obtained in our measurements provide a detailed mapping of the large number of molecular vibrations in these systems, excited by broadband ultrashort laser pulses, and make a thorough interpretation of the complex signal structure possible. In particular, an analysis of the data by applying Fourier transform methods to the time domain signal allows a clear identification of the excited porphyrin normal modes when compared with results on the mode structure from spectrally resolved (cw) spectroscopy. Altogether the method is capable of yielding detailed information on the dephasing behavior and on the relative spectral positions of the excited vibrations at the same time. Three porphyrin systems, dissolved in dichloromethane, were investigated: magnesium octaethylporphyrin, magnesium tetraphenylporphyrin and the free-base porphyrin octaethylporphyrin. The measurements were performed in the spectral region of the ring vibrations of the porphyrin macrocycle. We also provide a discussion of the expected signals on a theoretical basis by deriving the CARS third-order non-linear polarization for these experiments.

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Spectrally resolved fs-CARS as a probe of the vibrational dynamics of a large polyatomic molecule: magnesium octaethylporphyrin

Cited by 32 publications

References 28 publications

Vibrational Dynamics in Hydrogen-Bonded (Pyridine + Water) Complexes Studied by Spectrally Resolved Femtosecond CARS

Vibrational Dynamics in Hydrogen-Bonded (Pyridine + Water) Complexes Studied by Spectrally Resolved Femtosecond CARS

Coherent control of ultrafast optical four-wave mixing with two-colorω−3ωlaser pulses

Two‐dimensional probing of ground‐state vibrational dynamics in porphyrin molecules by fs‐CARS

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