Watching the Real-time Evolution of a Laser Modified Atom Using Attosecond Pulses

ORAL

Abstract

In the presence of even moderately strong laser fields, atomic states are heavily modified and develop rich structure. Such a laser dressed atom can be described using the Floquet theory in which the laser dressed states called Floquet states are composed of different Fourier components. In this work we use XUV attosecond pulses to excite a He atom from its ground state to near-infrared (NIR) laser dressed Floquet states, which are ionized by the dressing laser field. Quantum interferences between Fourier components of these Floquet states lead to oscillations in He ion yield as a function of time-delay between the XUV and NIR pulses. From the ion yield signal we measure the quantum phase difference between transition matrix elements to two different Fourier components as a function of both time-delay (instantaneous NIR intensity) and NIR pulse peak intensity. These measurements along with information from time-dependent Schrodinger equation simulations enable us to observe the real-time evolution of the laser modified atom as the dominant Floquet state mediating the ionization changes from the 5p Floquet state to the 2p Floquet state with increasing NIR intensity.

–

Authors

  • Niranjan Shivaram

  • Young-Yeal Song

    Brigham Young University, Colorado School of Mines, Colorado State University, Yale University, Department of Physics and Astronomy, Brigham Young University, Department of Mechanical Engineering, University of Utah, JILA, NIST and University of Colorado, University of Arizona, MIT, National Institute for Materials Science, Japan, Department of Mechanical Engineering, Brigham Young University, University of New Mexico, Iowa State University, Los Alamos National Lab XCP-2, Utah State University, Weber State University, New Mexico State University, College of Optical Science, University of Arizona, University of Nebraska, Lincoln, J.A. Woollam Co., U.S. Naval Research Laboratory, Arizona State University, BYU Nuclear Physics Group, Brigham Young University Physics and Astronomy, Los Alamos National Laboratory, University of Tsukuba, Japan, Colorado State University, NSF ERC for EUV science and technology, Center for Functional Nanomaterials, Brookhaven National Laboratory, University of Wisconsin, Madison, Utah Valley University, Argonne National Lab

  • Young-Yeal Song

    Brigham Young University, Colorado School of Mines, Colorado State University, Yale University, Department of Physics and Astronomy, Brigham Young University, Department of Mechanical Engineering, University of Utah, JILA, NIST and University of Colorado, University of Arizona, MIT, National Institute for Materials Science, Japan, Department of Mechanical Engineering, Brigham Young University, University of New Mexico, Iowa State University, Los Alamos National Lab XCP-2, Utah State University, Weber State University, New Mexico State University, College of Optical Science, University of Arizona, University of Nebraska, Lincoln, J.A. Woollam Co., U.S. Naval Research Laboratory, Arizona State University, BYU Nuclear Physics Group, Brigham Young University Physics and Astronomy, Los Alamos National Laboratory, University of Tsukuba, Japan, Colorado State University, NSF ERC for EUV science and technology, Center for Functional Nanomaterials, Brookhaven National Laboratory, University of Wisconsin, Madison, Utah Valley University, Argonne National Lab

  • Young-Yeal Song

    Brigham Young University, Colorado School of Mines, Colorado State University, Yale University, Department of Physics and Astronomy, Brigham Young University, Department of Mechanical Engineering, University of Utah, JILA, NIST and University of Colorado, University of Arizona, MIT, National Institute for Materials Science, Japan, Department of Mechanical Engineering, Brigham Young University, University of New Mexico, Iowa State University, Los Alamos National Lab XCP-2, Utah State University, Weber State University, New Mexico State University, College of Optical Science, University of Arizona, University of Nebraska, Lincoln, J.A. Woollam Co., U.S. Naval Research Laboratory, Arizona State University, BYU Nuclear Physics Group, Brigham Young University Physics and Astronomy, Los Alamos National Laboratory, University of Tsukuba, Japan, Colorado State University, NSF ERC for EUV science and technology, Center for Functional Nanomaterials, Brookhaven National Laboratory, University of Wisconsin, Madison, Utah Valley University, Argonne National Lab