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Strong Field Ionization of Atoms Irradiated with Two-Color Circularly Polarized Femtosecond Laser Fields: Rescattering in a Whole New Dimension

Event Details

Event Dates: 

Friday, June 17, 2016 - 1:30pm

Seminar Location: 

  • JILA X317

Speaker Name(s): 

Christopher Mancuso

Speaker Affiliation(s): 

JILA/Kapteyn-Murnane Group
Seminar Type/Subject

Scientific Seminar Type: 

  • JILA Thesis Defense

Event Details & Abstract: 

High-harmonic generation driven by two-color counter-rotating circularly polarized laser fields was recently demonstrated experimentally as a breakthrough source of bright, coherent, circularly polarized beams in the extreme ultraviolet and soft-x-ray regions. However, the conditions for optimizing the single-atom yield are significantly more complex than for linearly polarized driving lasers and are not fully understood. In this thesis, I present a comprehensive study of strong-field ionization–the complementary process to high-harmonic generation–driven by two-color circularly polarized fields. First, I describe a new experimental method that allows for the reconstruction of three-dimensional photoelectron angular distributions generated with two-color circularly polarized laser fields. Second, I present the first measurements of electron-ion rescattering in these fields, showing that the process can be systematically controlled by changing the parameters of the driving lasers. Finally, I present the first observation of nonsequential double ionization in two-color circularly polarized laser fields, showing how to optimize the yield of electrons that return to the parent ion at high energies. These findings help build an understanding of the single-atom physics behind high-harmonic generation. Additionally, since electrons ionized in two-color circularly polarized laser fields can be driven in two-dimensional trajectories before retuning to the parent ion, these findings will help inform the next-generation of experiments studying molecular dynamics on the ultrafast time scale.