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Non-collinear generation of angularly isolated circularly polarized high harmonics



Justin M. Shaw, Daniel Hickstein, Franklin Dollar, Patrik Grychtol, Jennifer Ellis, Carlos Hernandez-Garcia, Ronny J. Knut, Christian Gentry, Henry Kapteyn, Margaret Murnane


We generate ultrashort pulses of angularly isolated, circularly polarized extreme ultraviolet (EUV) light through the first implementation of noncollinear high harmonic generation with circularly polarized driving lasers. The noncollinear geometry offers numerous advantages over other harmonic generation methods, including the generation of higher photon energies, the ability to separate the harmonics from the pump beam without filters or optics, the production of both left and right circularly polarized light at the same wavelength, and the capability to separate the generated harmonics without a spectrometer. We perform an x-ray magnetic circular dichroism experiment on a 20 nm iron film, demonstrating the high degree of circularity of the generated EUV light as well as the capability to perform measurements of femtosecond-resolved magnetic dynamics. The mechanism of circular harmonic generation is explained with intuitive analytical descriptions in both the photon and wave models. Advanced numerical calculations suggest that the noncollinear mixing process will enable the first generation of isolated attosecond pulses of circularly polarized light.
Nature Communication


high harmonic generation, extreme ultraviolet, lasers, ultra-fast, ultrafast optics, circular dichroism


Shaw, J. , Hickstein, D. , Dollar, F. , Grychtol, P. , Ellis, J. , Hernandez-Garcia, C. , Knut, R. , Gentry, C. , Kapteyn, H. and Murnane, M. (2015), Non-collinear generation of angularly isolated circularly polarized high harmonics, Nature Communication, [online], (Accessed June 23, 2024)


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Created September 21, 2015, Updated November 10, 2018