Third-order-harmonic generation in coherently spinning molecules

We explore a pure optical method for enantioselective orientation of chiral molecules by means of laser fields with twisted polarization. Several field implementations are considered, including a pair of delayed, cross-polarized laser pulses, an optical centrifuge, and polarization-shaped pulses. We show that these schemes lead to out-of-phase time-dependent dipole signals for different enantiomers, and we also predict a substantial permanent molecular orientation persisting long after the laser fields are over. The underlying classical orientation mechanism common to all of these fields is discussed, and its operation is demonstrated for a range of chiral molecules of various complexity: hydrogen thioperoxide (HSOH), propylene oxide (CHCHCHO), and ethyl oxirane (CHCHCHCHO). The presented results demonstrate generality, versatility, and robustness of this optical method for manipulating molecular enantiomers in the gas phase.

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“…FIG. 10: Illustration of polarization shaped pulse [36,37]. Here the field twists in the clockwise direction (ϕp = 0), see equation 6.…”

Section: Enantioselective Orientation By Polarization Shaped Lasermentioning

confidence: 99%

Selective Orientation of Chiral Molecules by Laser Fields with Twisted Polarization

Tutunnikov

Gershnabel

Gold

et al. 2018

J. Phys. Chem. Lett.

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“…Typical rotational period of molecules is on the picosecond timescale, whereas the period of the circular polarization for an optical pulse is of the order of femtosecond. There are several types of twisted-polarization laser fields that have been demonstrated to induce UDR, including the double-pulse kick scheme, [53][54][55] the chiral train of ultrashort pulses, 56,57 the polarization-shaped pulse, 58,59 and the optical centrifuge. [60][61][62][63][64] Although these are very different fields, they all orient the molecular averaged angular momentum vector.…”

Section: Laser Fields With Twisted Polarizationmentioning

confidence: 99%

“…[44][45][46][47][48][49][50][51][52] Using sophisticated polarization-shaped laser fields, it is possible to orient the averaged angular momentum, thus preparing a unidirectionally rotating (UDR) molecular ensemble. The types of field combinations capable of initiating UDR include a pair of cross-polarized (typically at π∕4) time-delayed pulses, [53][54][55] chiral trains of short pulses, 56,57 polarization-shaped pulses, 58,59 and the optical centrifuge originally introduced almost 20 years ago [60][61][62][63][64] and improved more recently. 63,64 So far, much of the work involved small linear molecules.…”

Section: Introductionmentioning

confidence: 99%

Spatiotemporal rotational dynamics of laser-driven molecules

Lin

Tutunnikov

et al. 2020

Adv. Photon.

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Molecular alignment and orientation by laser fields has attracted significant attention in recent years, mostly due to new capabilities to manipulate the molecular spatial arrangement. Molecules can now be efficiently prepared for ionization, structural imaging, orbital tomography, and more, enabling, for example, shooting of dynamic molecular movies. Furthermore, molecular alignment and orientation processes give rise to fundamental quantum and classical phenomena like quantum revivals, Anderson localization, and rotational echoes, just to mention a few. We review recent progress on the visualization, coherent control, and applications of the rich dynamics of molecular rotational wave packets driven by laser pulses of various intensities, durations, and polarizations. In particular, we focus on the molecular unidirectional rotation and its visualization, the orientation of chiral molecules, and the three-dimensional orientation of asymmetric-top molecules. Rotational echoes are discussed as an example of nontrivial dynamics and detection of prepared molecular states.

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“…The theoretical model, described in ref. [34], allows computing molecular rotational dynamics for any polarization of the excitation pulse. The values of the alignment factor

⟨ \cos^{2} θ ⟩ > 1 / 3

signify the preferential alignment of the molecular axis along the polarization direction of the field.…”

Section: Conceptmentioning

confidence: 99%

Optical Imaging of Coherent Molecular Rotors

Bert

Prost

Tutunnikov

et al. 2020

Laser & Photonics Reviews

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Short laser pulses are widely used for controlling molecular rotational degrees of freedom and inducing molecular alignment, orientation, unidirectional rotation, and other types of coherent rotational motion. To follow the ultrafast rotational dynamics in real time, several techniques for producing molecular movies have been proposed based on the Coulomb explosion of rotating molecules, or recovering molecular orientation from the angular distribution of high harmonics. The present work offers and demonstrates a novel nondestructive optical method for direct visualization and recording of movies of coherent rotational dynamics in a molecular gas. The technique is based on imaging the time-dependent polarization dynamics of a probe light propagating through a gas of coherently rotating molecules. The probe pulse continues through a radial polarizer, and is then recorded by a camera. The technique is illustrated by implementing it with two examples of time-resolved rotational dynamics: alignment-antialignment cycles in a molecular gas excited by a single linearly polarized laser pulse, and unidirectional molecular rotation induced by a pulse with twisted polarization. This method may open new avenues in studies on fast chemical transformation phenomena and ultrafast molecular dynamics caused by strong laser fields of various complexities.

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Third-order-harmonic generation in coherently spinning molecules

Cited by 18 publications

References 38 publications

Selective Orientation of Chiral Molecules by Laser Fields with Twisted Polarization

Selective Orientation of Chiral Molecules by Laser Fields with Twisted Polarization

Spatiotemporal rotational dynamics of laser-driven molecules

Optical Imaging of Coherent Molecular Rotors

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