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Title: Air nonlinear dynamics initiated by ultra-intense lambda-cubic terahertz pulses

We report on the measurement of the instantaneous Kerr nonlinearity and the retarded alignment of air molecules CO{sub 2}, N{sub 2}, and O{sub 2} triggered by an intense, lambda-cubic terahertz pulse, a diffraction- and transform-limited single-cycle pulse. The strong-field, impulsive low-frequency excitation (3.9 THz) leads to field-free alignment dynamics of these molecules thanks to the terahertz-induced transient dipole moments in the otherwise non-polar molecules. The strong coupling to the terahertz electric transient results in the excitation of coherent large amplitude long-living rotational states at room temperature and ambient pressure. Beyond fundamental investigations of nonlinear properties in gases, our results suggest a route towards field-free molecular alignment at laser intensity well below the ionization threshold.
Authors:
 [1] ;  [1] ;  [2]
  1. SwissFEL, Paul Scherrer Institut, 5232 Villigen PSI (Switzerland)
  2. (Switzerland)
Publication Date:
OSTI Identifier:
22398991
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 18; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; AIR; ALIGNMENT; CARBON DIOXIDE; DIFFRACTION; DIPOLE MOMENTS; ELECTROMAGNETIC PULSES; EXCITATION; KERR EFFECT; LASERS; MOLECULES; NONLINEAR PROBLEMS; ROTATIONAL STATES; TEMPERATURE RANGE 0273-0400 K; THZ RANGE; TRANSIENTS