Time-domain coherent active Raman spectroscopy of a free-nitrogen jet

Akhmanov, S. A.; Koroteev, N. I.; Magnitskii, S. A.; Morozov, V.B.; Tarasevich, A. P.; Tunkin, V. G.

doi:10.1364/josab.2.000640

Cited by 40 publications

(9 citation statements)

References 6 publications

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“…Picosecond time-resolved CARS measurements have been demonstrated for high resolution, Fourier transform Raman spectroscopy of methane and nitrogen in free jet expansions. 13,14 In contrast, in the experiments reported here, femtosecond pulses are used to excite the entire set of rovibrational transitions associated with a particular vibrational motion in a large molecule and then a femtosecond probe pulse monitors the time evolution of the excited coherence. We observe two different mechanisms for decay of the coherence, depending on the anisotropy of the Raman polarizability in the molecules.…”

Section: Introductionmentioning

confidence: 99%

Femtosecond time-resolved studies of coherent vibrational Raman scattering in large gas-phase molecules

Hayden

Chandler

1995

The Journal of Chemical Physics

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Results are presented from femtosecond time-resolved coherent Raman experiments in which we excite and monitor vibrational coherence in gas-phase samples of benzene and 1,3,5-hexatriene. Different physical mechanisms for coherence decay are seen in these two molecules. In benzene, where the Raman polarizability is largely isotropic, the Q branch of the vibrational Raman spectrum is the primary feature excited. Molecules in different rotational states have different Q-branch transition frequencies due to vibration–rotation interaction. Thus, the macroscopic polarization that is observed in these experiments decays because it has many frequency components from molecules in different rotational states, and these frequency components go out of phase with each other. In 1,3,5-hexatriene, the Raman excitation produces molecules in a coherent superposition of rotational states, through (O, P, R, and S branch) transitions that are strong due to the large anisotropy of the Raman polarizability. The coherent superposition of rotational states corresponds to initially spatially oriented, vibrationally excited, molecules that are freely rotating. The rotation of molecules away from the initial orientation is primarily responsible for the coherence decay in this case. These experiments produce large (∼10% efficiency) Raman shifted signals with modest excitation pulse energies (10 μJ) demonstrating the feasibility of this approach for a variety of gas phase studies.

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Section: Introductionmentioning

confidence: 99%

Femtosecond time-resolved studies of coherent vibrational Raman scattering in large gas-phase molecules

Hayden

Chandler

1995

The Journal of Chemical Physics

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“…Time‐resolved broadband picosecond CARS, with pulse widths ranging from tens to hundreds of picoseconds, allows researchers to overcome the shortcomings of ns‐laser‐based CARS outlined above. Since the non‐resonant response of a medium damps faster than the resonant response, it is possible to delay the probe pulse in time with respect to the pump and Stokes pulses to suppress the non‐resonant contribution to the CARS signal . Moreover, another advantage of time‐resolved ps CARS is to directly measure linewidth of the target molecules with the presence of unknown collisional partners.…”

Section: Introductionmentioning

confidence: 99%

Non‐collinear optical parametric amplifier for time‐resolved broadband picosecond CARS

Vereshchagin

Morozov

et al. 2014

J Raman Spectroscopy

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We demonstrate generation of broadband high‐intensity picosecond pulses using a non‐collinear optical parametric amplifier, seeded with a broadband cavity‐less dye laser and pumped using the second harmonic of a picosecond Nd:YAG laser. With appropriate choice of the pump‐seed non‐collinearity angle, we observed energy conversion from the pump to the signal wave of around 15%, with the bandwidth of the amplified radiation around 445 cm−1 (20.7 nm) centered around 680 nm. An energy of 1.2 mJ per pulse of duration around 26 ps has been achieved. A light source with such parameters could be suitable for use in time‐resolved broadband picosecond Coherent anti‐Stokes Raman scattering. Copyright © 2014 John Wiley & Sons, Ltd.

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“…10 Femtosecond CARS was effectively used for the determination of J-dependencies of collisional line shifts 11,12 and line broadening 13 coefficients in H 2 molecules in pure hydrogen and mixtures on the basis of measurements at densities up to 50 amagat. Femtosecond CARS measurements have been demonstrated to be very sensitive to pressure variations and RET process manifestation in N 2 Q-branches between 0.2 ð 10 5 and 5 ð 10 5 Pa pressures.…”

Section: Introductionmentioning

confidence: 99%

Collisionally induced dephasing and rotational energy transfer in the CO₂ Fermi dyad ‘red’ Q‐branch 1285 cm⁻¹

Arakcheev

Киреев

Morozov

et al. 2007

J Raman Spectroscopy

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The present paper is focused on the development of an adequate description of collisionally induced dephasing and rotational energy transfer (RET) in the CO 2 Fermi dyad n 1 /2n 2 . We have made comparative analysis of two approaches to RET simulation for the 2n 2 Q-branch 1285 cm −1 based on spectral exchange (SE) and rotational relaxation (RR) ideas. A special fitting procedure based on the minimization of an approximation error has been developed for fitting theoretical impulse responses to the experimental ones measured by picosecond time-domain coherent anti-Stokes Raman spectroscopy (CARS). A series of experiments on frequency-domain CARS were carried out in order to improve measurements of the dephasing time T 2 and to extend the simulation to the whole gas density range using a uniform set of fitting parameters. Special attention was paid to a detailed analysis of the rotational structure manifestation in the impulse response beating structure. In the case of the 'red' Q-branch, the RR model proved to be more appropriate in comparison with the SE model. It is shown that the rotational structure contribution to the time-domain signal decay and the cumulative spectral width remains essential and comparable with the collisional dephasing contribution up to the highest gas densities.

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Time-domain coherent active Raman spectroscopy of a free-nitrogen jet

Cited by 40 publications

References 6 publications

Femtosecond time-resolved studies of coherent vibrational Raman scattering in large gas-phase molecules

Femtosecond time-resolved studies of coherent vibrational Raman scattering in large gas-phase molecules

Non‐collinear optical parametric amplifier for time‐resolved broadband picosecond CARS

Collisionally induced dephasing and rotational energy transfer in the CO₂ Fermi dyad ‘red’ Q‐branch 1285 cm⁻¹

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Time-domain coherent active Raman spectroscopy of a free-nitrogen jet

Cited by 40 publications

References 6 publications

Femtosecond time-resolved studies of coherent vibrational Raman scattering in large gas-phase molecules

Femtosecond time-resolved studies of coherent vibrational Raman scattering in large gas-phase molecules

Non‐collinear optical parametric amplifier for time‐resolved broadband picosecond CARS

Collisionally induced dephasing and rotational energy transfer in the CO2 Fermi dyad ‘red’ Q‐branch 1285 cm−1

Contact Info

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Collisionally induced dephasing and rotational energy transfer in the CO₂ Fermi dyad ‘red’ Q‐branch 1285 cm⁻¹