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Title: Probing the origin of elliptical high-order harmonic generation from aligned molecules in linearly polarized laser fields

Journal Article · · Physical Review. A
 [1];  [2];  [1]
  1. Department of Chemistry, University of Kansas, Lawrence, Kansas 66045 (United States)
  2. Department of Physics, St. Petersburg State University, St. Petersburg 198504 (Russian Federation)

A recent experiment [Phys. Rev. Lett. 102, 073902 (2009)] has demonstrated that elliptically polarized high-order harmonic generation can be produced from linearly polarized driving fields for aligned molecular systems. In order to reveal the underlying physical mechanisms of elliptical harmonics, we present fully ab initio and high-precision calculations and analyses of the amplitude, phase, and polarization state of the harmonic radiation from molecular hydrogen ions with arbitrary orientation. We find that high ellipticity arises from molecular orbital symmetry and two-center interference effects. Our ab initio exploration and findings lead to a general rule that the ellipticity becomes high for molecular orbitals represented by a symmetric combination of atomic orbitals, whereas it becomes low for molecular orbitals represented by an antisymmetric combination. This finding also applies to the general case of aligned linear molecules.

OSTI ID:
21452604
Journal Information:
Physical Review. A, Vol. 82, Issue 4; Other Information: DOI: 10.1103/PhysRevA.82.043829; (c) 2010 The American Physical Society; ISSN 1050-2947
Country of Publication:
United States
Language:
English