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"Generating bright circularly-polarized high harmonics from the extreme ultraviolet to the soft x-ray range"

Dr. Patrik Grychtol
JILA, University of Colorado, Boulder


Circularly polarized light in the extreme ultraviolet (EUV) and soft x-ray regions of the electromagnetic spectrum is extremely useful for exploring chirality-sensitive light-matter interactions. Specifically, magnetic circular dichroism (XMCD) makes it possible to extract element-specific information about the magnetic state of matter and its interaction with phononic and electronic degrees of freedom on fundamental scales in space and time. To date, circularly polarized EUV and soft x-ray beams were mostly restricted to large-scale electron acceleration facilities, such as synchrotrons and free electron lasers. However, in a recent breakthrough, it was shown that two-color counter-rotating circularly-polarized laser fields can enable the generation of circularly polarized attosecond pulse trains that are bright enough for applications using high harmonic generation (HHG). Besides presenting key findings of our HHG studies on ultrafast spin dynamics, I will introduce a simple setup which allows for the efficient generation of bright circular harmonics up to photon energies of 180eV. In addition, I will present the results of the first study on strong-field ionization of atoms in two-color circularly polarized fields, uncovering the mechanisms behind the generation of circularly-polarized high harmonics. Our results not only stress the universality of our approach that will enable its extension into and beyond the water-window, but also point they towards the remarkable potential for controlling HHG waveforms.

Wednesday, November 11, 2015
IQSE 578, 12:30 Noon
Mitchell Physics Building

Institute for Quantum Science and Engineering
Texas A&M University

(Pizza, salad, and soda to be served at 12:00 noon)

Host: Dr. Marlan Scully