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Imaging of Optical Lattices via High Harmonic Generation

POSTER

Abstract

Noah Welikson and Andreas Becker

JILA and Department of Physics, University of Colorado, Boulder,

CO 80309-0440, USA

High harmonic generation (HHG) is a highly nonlinear process to upconvert laser light frequencies from the optical and near-infrared into the extreme ultraviolet and the soft x-ray regime [3]. HHG is understood through a process in which electrons are ionized from their parent nuclei by an intense laser pulse, picking up energy via the interaction with the laser field before recombining with the parent nuclei and releasing this energy in the form of radiation at multiples of the driver frequency [4, 1]. Recently, there has been much effort in applying such HHG sources for the use in high-definition imaging of materials [2]. We further explore the limits of these techniques by simulating the direct stimulation of HHG in an optical lattice. Thus far we have applied numerical solutions of the time-dependent Schr ̈odinger equation to calculate the microscopic harmonic spectrum emitted by atoms arranged in a lattice in a high intensity infrared laser field, and propagated this radiation into the far-field to generate a diffraction image. We show that certain phase reconstruction techniques used in coherent diffracting imaging can be applied to these diffraction data to generate high definition images of the lattice.

References

[1] P. B. Corkum. “Plasma perspective on strong field multiphoton ionization”. In: Phys. Rev. Lett. 71 (13 Sept. 1993), pp. 1994–1997. doi: 10 . 1103 /PhysRevLett.71.1994.

[2] Robert M. Karl et al. “Full-field imaging of thermal and acoustic dynamics in an individual nanostructure using tabletop high harmonic beams”. In: Science Advances 4.10 (2018), eaau4295. doi: 10.1126/sciadv.aau4295.

[3] Tenio Popmintchev et al. “Bright Coherent Ultrahigh Harmonics in the keV X-ray Regime from Mid-Infrared Femtosecond Lasers”. In: Science(New York, N.Y.) 336 (June 2012), pp. 1287–91. doi: 10.1126/science.1218497.

[4] K. J. Schafer et al. “Above threshold ionization beyond the high harmonic cutoff”. In: Phys. Rev. Lett. 70 (11 Mar. 1993), pp. 1599–1602. doi: 10.1103/PhysRevLett.70.1599.

Presenters

  • Noah Welikson

    University of Colorado, Boulder

Authors

  • Noah Welikson

    University of Colorado, Boulder

  • Andreas Becker

    JILA, JILA & Department of Physics University of Colorado, Boulder