Long-lasting field-free alignment of large molecules inside helium nanodroplets

Molecules with their axes sharply confined in space, available through laser-induced alignment methods, are essential for many current experiments, including ultrafast molecular imaging. For these applications the aligning laser field should ideally be turned-off, to avoid undesired perturbations, a...

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Bibliographic Details
Published in:Nature communications 2019-01, Vol.10 (1), p.133-133, Article 133
Main Authors: Chatterley, Adam S., Schouder, Constant, Christiansen, Lars, Shepperson, Benjamin, Rasmussen, Mette Heidemann, Stapelfeldt, Henrik
Format: Article
Language:English
Subjects:
140/125
639/638/440/94
639/766/36/1121
639/766/36/1124
Alignment
Environmental effects
Field ionization
Helium
Humanities and Social Sciences
Ionization
Lasers
Molecular rotation
multidisciplinary
Oligomers
Science
Science (multidisciplinary)
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Summary:Molecules with their axes sharply confined in space, available through laser-induced alignment methods, are essential for many current experiments, including ultrafast molecular imaging. For these applications the aligning laser field should ideally be turned-off, to avoid undesired perturbations, and the strong alignment should last long enough that reactions and dynamics can be mapped out. Presently, this is only possible for small, linear molecules and for times less than 1 picosecond. Here, we demonstrate strong, field-free alignment of large molecules inside helium nanodroplets, lasting >10 picoseconds. One-dimensional or three-dimensional alignment is created by a slowly switched-on laser pulse, made field-free through rapid pulse truncation, and retained thanks to the impeding effect of the helium environment on molecular rotation. The opportunities field-free aligned molecules open are illustrated by measuring the alignment-dependent strong-field ionization yield of dibromothiophene oligomers. Our technique will enable molecular frame experiments, including ultrafast excited state dynamics, on a variety of large molecules and complexes. Strong molecular alignment without a laser field present is important for fundamental experiments in molecular science, but so far this has not been obtained for complex molecules. Here the authors use a shaped laser pulse to demonstrate field-free alignment of complex molecules in helium droplets.
ISSN:2041-1723
2041-1723
DOI:10.1038/s41467-018-07995-0