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Title: Helicity-selective phase-matching and quasi-phase matching of circularly polarized high-order harmonics: towards chiral attosecond pulses

Phase matching of circularly polarized high-order harmonics driven by counter-rotating bi-chromatic lasers was recently predicted theoretically and demonstrated experimentally. In that work, phase matching was analyzed by assuming that the total energy, spin angular momentum and linear momentum of the photons participating in the process are conserved. Here we propose a new perspective on phase matching of circularly polarized high harmonics. We derive an extended phase matching condition by requiring a new propagation matching condition between the classical vectorial bi-chromatic laser pump and harmonics fields. This allows us to include the influence of the laser pulse envelopes on phase matching. Here, we find that the helicity dependent phase matching facilitates generation of high harmonics beams with a high degree of chirality. Indeed, we present an experimentally measured chiral spectrum that can support a train of attosecond pulses with a high degree of circular polarization. Moreover, while the degree of circularity of the most intense pulse approaches unity, all other pulses exhibit reduced circularity. Lastly, this feature suggests the possibility of using a train of attosecond pulses as an isolated attosecond probe for chiral-sensitive experiments.
 [1] ;  [2] ;  [2] ;  [2] ;  [2] ;  [3] ;  [1] ;  [2] ;  [2] ;  [2] ;  [2] ;  [2] ;  [1]
  1. Technion, Haifa (Israel). Solid State Inst. and Physics Dept.
  2. Univ. of Colorado, Boulder and National Inst. of Standards and Technology (NIST), CO (United States). Dept. of Physics and JILA
  3. Technion, Haifa (Israel). Solid State Inst. and Physics Dept.; Ort Braude College, Karmiel (Israel). Dept. of Physics and Optical Engineering
Publication Date:
Grant/Contract Number:
SC0002002; 225/14
Published Article
Journal Name:
Journal of Physics. B, Atomic, Molecular and Optical Physics
Additional Journal Information:
Journal Volume: 49; Journal Issue: 12; Journal ID: ISSN 0953-4075
IOP Publishing
Research Org:
Univ. of Colorado, Boulder, CO (United States)
Sponsoring Org:
USDOE; USA–Israel Binational Science Foundation (BSF); Israel Science Foundation; German Research Foundation (DFG)
Country of Publication:
United States
74 ATOMIC AND MOLECULAR PHYSICS; circularly polarized high harmonic generation; phase matching; ultrafast chiral physics; attosecond pulses
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1254067; OSTI ID: 1435718