Vibrational ladder climbing in NO by (sub)picosecond frequency-chirped infrared laser pulses

Maas, D. J. H. C.; Duncan, D. I.; Vrijen, R. B.; Zande, Wim J. van der; Noordam, L. D.

doi:10.1016/s0009-2614(98)00531-4

Cited by 127 publications

(74 citation statements)

References 23 publications

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“…As a reference on the noise level, we also plot the differential spectrum obtained for a time delay of 140 ps (curve b), where only a small positive peak remains at frequency 10. Curve b is shifted down for clarity. 6 using a similar technique. It also roughly followed the law expected for a harmonic oscillator linearly coupled to a thermal bath (19) with decay rates proportional to the vibrational quantum number.…”

Section: Figmentioning

confidence: 99%

“…Coherent vibrational climbing can be viewed also as a rapid adiabatic passage leading to efficient excitation of the upper vibrational states, with an efficiency that in theory can be close to 100% because of the coherent nature of the interaction. Vibrational climbing has been demonstrated in small molecules, such as W(CO) 6 (3)(4)(5), NO (6), CO adsorbed on a Ru (001) surface (7), Cr(CO) 6 (8), Mo(CO) 6 (5), Fe(CO) 5 (5), and CH 2 N 2 (9). In this article, we report on the demonstration of coherent vibrational climbing in a biological system, carboxyhemoglobin (HbCO).…”

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confidence: 99%

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Coherent vibrational climbing in carboxyhemoglobin

Ventalon

Fraser

Vos

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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We demonstrate vibrational climbing in the CO stretch of carboxyhemoglobin pumped by midinfrared chirped ultrashort pulses. By use of spectrally resolved pump-probe measurements, we directly observed the induced absorption lines caused by excited vibrational populations up to v ‫؍‬ 6. In some cases, we also observed stimulated emission, providing direct evidence of vibrational population inversion. This study provides important spectroscopic parameters on the CO stretch in the strong-field regime, such as transition frequencies and dephasing times up to the v ‫؍‬ 6 to v ‫؍‬ 7 vibrational transition. We measured equally spaced vibrational transitions, in agreement with the energy levels of a Morse potential up to v ‫؍‬ 6. It is interesting that the integral of the differential absorption spectra was observed to deviate far from zero, in contrast to what one would expect from a simple onedimensional Morse model assuming a linear dependence of dipole moment with bond length.T he recent availability of ultrashort and intense midinfrared pulses in a compact setup (1) provides a convenient means for controlling the nuclear motion of molecules (2). With infrared pulses, only vibrational transitions are addressed while the molecule remains in its electronic ground state during the entire interaction. This makes such an approach particularly suited to complex systems such as proteins. Another fascinating possibility opened up by infrared vibrational control is the prospect of exploring the potential energy surface far from the harmonic region up to the transition state of intraprotein reactions.Coherent vibrational climbing consists of exciting a molecular vibration with an ultrashort midinfrared pulse, the broadband spectrum of which encompasses several vibrational transitions of the molecule. Indeed, these transition frequencies become smaller and smaller while climbing the ladder because of the molecular anharmonicity. Therefore, the climbing efficiency can be increased dramatically when using a negatively chirped pulse so that its high-frequency components, resonant with the lower transitions of the ladder, precede its low-frequency components, resonant with the upper transitions of the ladder. Coherent vibrational climbing can be viewed also as a rapid adiabatic passage leading to efficient excitation of the upper vibrational states, with an efficiency that in theory can be close to 100% because of the coherent nature of the interaction. Vibrational climbing has been demonstrated in small molecules, such as W(CO) 6 (3-5), NO (6), CO adsorbed on a Ru (001) surface (7), Cr(CO) 6 (8), Mo(CO) 6 (5), Fe(CO) 5 (5), and CH 2 N 2 (9). In this article, we report on the demonstration of coherent vibrational climbing in a biological system, carboxyhemoglobin (HbCO). This system was chosen rather than carboxymyoglobin, in which different CO-bound configurations result in an inhomogeneous broadening of the absorption line (10). Experimental MethodsThe 800-nm pulses produced by a titanium͞sapphire regenerative amplifier (Hurrican...

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Section: Figmentioning

confidence: 99%

mentioning

confidence: 99%

Coherent vibrational climbing in carboxyhemoglobin

Ventalon

Fraser

Vos

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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“…For example total population transfer has been achieved via multilevel ladder climbing [4][5][6][7][8][9] and Stimulated Raman Adiabatic Passage [10].…”

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confidence: 99%

Observation of Coherent Transients in Ultrashort Chirped Excitation of an Undamped Two-Level System

et al. 2001

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The effects of Coherent excitation of a two level system with a linearly chirped pulse are studied theoretically and experimentally (in Rb (5s -5p)) in the low field regime. The Coherent Transients are measured directly on the excited state population on an ultrashort time scale. A sharp step corresponds to the passage through resonance. It is followed by oscillations resulting from interferences between off-resonant and resonant contributions. We finally show the equivalence between this experiment and Fresnel diffraction by a sharp edge.Coherent excitation of atomic transitions is a general phenomenon occurring whenever electromagnetic radiation interacts with atoms. This interaction may result in various kinds of processes, for example Rabi oscillations, free induction decay, adiabatic population transfer and Coherent Transients (CT) [1]. By simply varying the temporal shape of the pulses, a great variety of systems can be manipulated such as spins in Nuclear Magnetic Resonance [2] or atomic and molecular systems in coherent control schemes [3]. We consider here the simplest case of linearly chirped pulses where the "instantaneous frequency" drifts in time.Depending on the frequency sweep and on the intensity, adiabatic following can be observed with a significant population transfer. For example total population transfer has been achieved via multilevel ladder climbing [4][5][6][7][8][9] and Stimulated Raman Adiabatic Passage [10].On the contrary if the adiabaticity criterion is not fulfilled, the final population depends crucially on the pulse integral and CT dominate the interaction. This letter presents theoretical and experimental studies of these Coherent Transients. Although many works have dealt with the transfer efficiency into the final state, we report here the first direct observation of these transients on a subpicosecond time scale. The CT result in oscillating population. This is a signature of interferences between resonant and non-resonant excitation. A detailed understanding of this behaviour is crucial to analyze pumpprobe experiments in which dynamics takes place on the same time scale as laser interaction. Due to the difficulty to control properly the laser pulses, the effects of CT are most often ignored [11].Similarities can be found with optical CT observed in the experiments of free induction decay or photon echoes which provide relaxation rates [12][13][14]. In these experiments, they observed on the transmitted optical signal, a beat between initially induced polarisation of the medium at resonance and a near-resonant laser. In the particular case of a single chirped optical pulse, the beat frequency increases linearly after passage through resonance, following the increase of resonance mismatch [15]. On the contrary to these previous studies, the present report involves CT directly observed on the population before relaxation becomes significant. The beats result here from interferences between the resonant and non-resonance excitation paths. The passage through resonance does not ...

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“…Enhancement of ladder-climbing processes in down-chirped laser fields have been reported in the mid-IR around 5 μm [29,30], corresponding to a fundamental vibrational transition in the molecules of interest. The experiments of this work have been performed around 800 nm corresponding to photon energies of 1.5 eV, much larger than the energy gaps between adjacent vibrational states.…”

Section: Comparison Of Molecules and Atomsmentioning

confidence: 99%

“…An illustrative picture for the interpretation of the sigmoidal function is the ladder-climbing model depicted in Figure 9, a common explanation of anharmonicity effects [29]. Ultrashort laser pulses comprise a broad spectrum and therefore consist of photons with different wavelengths and energy, respectively.…”

Section: Comparison Of Molecules and Atomsmentioning

confidence: 99%

Photoionization Yields in Intense fs-Laser Fields – A Systematic Investigation of Chirp Effects

Reusch

Griebe

Karges

et al. 2015

Zeitschrift Für Physikalische Chemie

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Abstract:The femtosecond laser ionization of several small hydrocarbon molecules (methane, ethane, propane) has been investigated as a function of the second order spectral phase (linear chirp) of laser pulses centered at = 807 nm.Ion yields are demonstrated to depend markedly on the linear chirp parameter. At laser intensities exceeding 5 × 10 14 W/cm 2 the ionization characteristics resemble an intensity-driven process, i.e. the largest ion yield is observed for a close to transform-limited laser pulse. For smaller laser intensities a pronounced sign effect in the chirp dependence appears, i.e. the maximum ion yield is observed for a negative linear chirp parameter of several hundred to thousand fs 2 . We suggest that this sign effect is connected to the anharmonicity of the electronic potentials involved. This suggestion is supported by the fact that basically no sign effect in the chirp dependence is observed for the noble gases argon, krypton and xenon. We further suggest that the electronic polarizability and structure plays some role as methanol does not show a marked sign-dependent chirp effect.

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Vibrational ladder climbing in NO by (sub)picosecond frequency-chirped infrared laser pulses

Cited by 127 publications

References 23 publications

Coherent vibrational climbing in carboxyhemoglobin

Coherent vibrational climbing in carboxyhemoglobin

Observation of Coherent Transients in Ultrashort Chirped Excitation of an Undamped Two-Level System

Photoionization Yields in Intense fs-Laser Fields – A Systematic Investigation of Chirp Effects

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