Controlling the Orientation of Polar Molecules with Combined Electrostatic and Pulsed, Nonresonant Laser Fields

Sakai, Hirofumi; Minemoto, Shinichirou; Nanjo, Hiroshi; Tanji, Haruka; Suzuki, Takayuki

doi:10.1103/physrevlett.90.083001

Cited by 248 publications

(126 citation statements)

References 20 publications

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“…As suggested by Friedrich and Herschbach a decade ago [16,17], and later demonstrated experimentally [10,[18][19][20][21], orientation can be added to alignment by combining the strong laser field with a weak static electric field. Therefore, we use 1D orientation to denote 1D alignment and, simultaneously, a preferred direction of the permanent dipole moment.…”

Section: Introductionmentioning

confidence: 99%

Laser-induced 3D alignment and orientation of quantum state-selected molecules

Nevo

Holmegaard

Nielsen

et al. 2009

Phys. Chem. Chem. Phys.

109

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A strong inhomogeneous static electric field is used to spatially disperse a rotationally cold supersonic beam of 2,6-difluoroiodobenzene molecules according to their rotational quantum state. The molecules in the lowest lying rotational states are selected and used as targets for 3-dimensional alignment and orientation. The alignment is induced in the adiabatic regime with an elliptically polarized, intense laser pulse and the orientation is induced by the combined action of the laser pulse and a weak static electric field. We show that the degree of 3-dimensional alignment and orientation is strongly enhanced when rotationally state-selected molecules, rather than molecules in the original molecular beam, are used as targets. 36.40.Wa

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Section: Introductionmentioning

confidence: 99%

Laser-induced 3D alignment and orientation of quantum state-selected molecules

Nevo

Holmegaard

Nielsen

et al. 2009

Phys. Chem. Chem. Phys.

109

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“…To scale this technique to still larger molecules, it may be necessary to employ longer wavelength laser fields to avoid loworder resonances, ensuring that the Stark interaction with the molecular polarizability is dominant. With the addition of half-cycle terahertz fields [13], it may also be possible to produce field-free 3D orientation [2,14].…”

Section: Fig 2 (Color Online)mentioning

confidence: 99%

Field-Free Three-Dimensional Alignment of Polyatomic Molecules

et al. 2006

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We experimentally demonstrate field-free, three-dimensional alignment (FF3DA) of polyatomic asymmetric top molecules. We achieve FF3DA in sulfur dioxide gas using two time-delayed, orthogonally polarized, nonresonant, femtosecond laser pulses. Our method avoids the use of rotational revivals and is therefore more robust to temperature. The alignment is probed using time-delayed coincidence Coulomb explosion imaging. FF3DA will be important for all molecular imaging, dynamics, or spectroscopy experiments for which random alignment leads to a loss of information. DOI: 10.1103/PhysRevLett.97.173001 PACS numbers: 33.15.Bh, 33.55.Be, 33.80.ÿb The random alignment of gas phase molecules generally reduces the information content of a measurement made in the laboratory frame. The situation is analogous to the well-known case of powder, as opposed to crystal, x-ray diffraction. To ameliorate this situation, it is necessary to define the direction of the molecules in the lab frame prior to making a measurement. Polyatomic molecules are generally asymmetric rotors with three distinct axes of rotation. Three-dimensional alignment, i.e., the alignment of all three molecular axes, was achieved in the presence of an aligning laser field [1,2], but this field strongly perturbs the system, distorting the electronic and vibrational structure of the molecule [3] and preventing the measurement of innate molecular properties. Field-free one-dimensional alignment, i.e., alignment of a single molecular axis, was achieved using a short laser pulse [4,5], and by the rapid turn off of an adiabatic strong laser field [6]. In these experiments, maximal alignment is produced after the pulse [4,7] when the molecule is field-free, followed by periodic revivals of the rotational wave packet [4]. The rotational energy level spacings for asymmetric tops are much less regular than for linear and symmetric top molecules. This complicates the rotational wave-packet evolution for asymmetric rotors, reducing alignment at revivals. The degradation of alignment worsens at elevated rotational temperatures due to the incoherent contributions of thermally populated rotational states which can lead to complete obfuscation of the rotational revival structure. This is a challenge for experimentalists since rotational cooling is often compromised in order to produce sufficiently dense molecular beams.Here we report the experimental demonstration of a general, flexible, and robust method for producing fieldfree, three-dimensional alignment (FF3DA) of polyatomic molecules. This method makes use of the prompt alignment occurring just after the laser pulse and is much more robust with respect to temperature effects than is an earlier proposal for FF3DA at rotational revivals [8]. This technique is broadly applicable and we demonstrate it here for the asymmetric top molecule SO 2 .Our method is based upon the use of two time-separated, perpendicularly polarized, nonresonant, femtosecond laser pulses. The first laser pulse produces postpulse 1D alignment of the...

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“…Targets of molecules lacking an inversion center (i.e., polar molecules) must, in addition to having their axes confined, possess a directional order of their dipole moment, i. e., the molecules must be oriented as well as aligned [14]. One approach to efficient orientation and alignment is through the combined action of a laser pulse and a weak static electric field [18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Ionization of one- and three-dimensionally-oriented asymmetric-top molecules by intense circularly polarized femtosecond laser pulses

et al. 2011

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We present a combined experimental and theoretical study on strong-field ionization of a three-dimensionallyoriented asymmetric top molecule, benzonitrile (C 7 H 5 N), by circularly polarized, nonresonant femtosecond laser pulses. Prior to the interaction with the strong field, the molecules are quantum-state selected using a deflector and three-dimensionally (3D) aligned and oriented adiabatically using an elliptically polarized laser pulse in combination with a static electric field. A characteristic splitting in the molecular frame photoelectron momentum distribution reveals the position of the nodal planes of the molecular orbitals from which ionization occurs. The experimental results are supported by a theoretical tunneling model that includes and quantifies the splitting in the momentum distribution. The focus of the present article is to understand strong-field ionization from 3D-oriented asymmetric top molecules, in particular the suppression of electron emission in nodal planes of molecular orbitals. In the preceding article [Dimitrovski et al., Phys. Rev. A 83, 023405 (2011)] the focus is to understand the strong-field ionization of one-dimensionally-oriented polar molecules, in particular asymmetries in the emission direction of the photoelectrons.

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Controlling the Orientation of Polar Molecules with Combined Electrostatic and Pulsed, Nonresonant Laser Fields

Cited by 248 publications

References 20 publications

Laser-induced 3D alignment and orientation of quantum state-selected molecules

Laser-induced 3D alignment and orientation of quantum state-selected molecules

Field-Free Three-Dimensional Alignment of Polyatomic Molecules

Ionization of one- and three-dimensionally-oriented asymmetric-top molecules by intense circularly polarized femtosecond laser pulses

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