Avner Fleischer

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Circularly-polarized extreme ultraviolet and X-ray radiation is useful for analysing the structural, electronic and magnetic properties of materials. To date, such radiation has only been available at large-scale X-ray facilities such as synchrotrons. Here, we demonstrate the first bright, phase-matched, extreme ultraviolet circularly-polarized high(More)
Christopher A. Mancuso,1 Daniel D. Hickstein,1,* Patrik Grychtol,1 Ronny Knut,1 Ofer Kfir,2 Xiao-Min Tong,3 Franklin Dollar,1 Dmitriy Zusin,1 Maithreyi Gopalakrishnan,1 Christian Gentry,1 Emrah Turgut,1 Jennifer L. Ellis,1 Ming-Chang Chen,4 Avner Fleischer,2,5 Oren Cohen,2 Henry C. Kapteyn,1 and Margaret M. Murnane1 1JILA and Department of Physics,(More)
We demonstrate experimentally sparsity-based super-resolution of coherent diffraction imaging (CDI) with extreme UV radiation. We also present the first experimental CDI of a practically one-dimensional object, overcoming the well-known ambiguity problem in onedimensional phase retrieval. OSCI: (190.2620) Harmonic generation and mixing; (070.0070) Fourier(More)
Phase-retrieval problems of one-dimensional (1D) signals are known to suffer from ambiguity that hampers their recovery from measurements of their Fourier magnitude, even when their support (a region that confines the signal) is known. Here we demonstrate sparsity-based coherent diffraction imaging of 1D objects using extreme-ultraviolet radiation produced(More)
We propose and numerically demonstrate a method for obtaining high-harmonic radiation with desirable elliptical polarization. Atoms are shined by a combination of a strong linearly-polarized laser field and an additional weak field, which is elliptically polarized in a plane perpendicular to the polarization direction of the strong field. The strong driver(More)
We predict and investigate the emission of high-order harmonics by atoms that cross intense laser hot spots that last for a nanosecond or longer. An atom that moves through a nanometer-scale hot spot at characteristic thermal velocity can emit high-order harmonics in a similar fashion to an atom that is irradiated by a short-duration (picosecond-scale)(More)
Phase matching of circularly polarized high-order harmonics driven by counter-rotating bichromatic 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(More)
We theoretically explore a scheme for generation of bright circularly and elliptically polarized high-order harmonics by bursts of linearly polarized pulses with a rotating polarization axis. Circularly polarized harmonics are formed if the bursts are comprised of N pulses that uphold an N-fold rotational symmetry, for N > 2. Rotating the polarization axes(More)
We propose a scheme for producing attosecond pulses with sophisticated spatio-spectral waveforms. The profile of a seed attosecond pulse is modified and its central frequency is up-converted through interaction with an infrared pump pulse. The transverse profile of the infrared beam and a spatiotemporal shift between the seed and infrared pulses are used(More)