Affiliation:
1. University of Ottawa
2. SLAC National Accelerator Laboratory
Abstract
Nanostructured optical surfaces allow exquisite control over linear and
nonlinear light interactions, where the surface actively creates new
frequencies up to high-order harmonics of an intense infrared driving
laser field. The function and performance of these surfaces depend
sensitively on the distribution of the high-harmonic fields in and
between the nanostructured elements, as the high-harmonic wavelength
becomes comparable to the nanoscale features of the surface. Imaging
the nonlinear response at the active surface with nanometer resolution
would greatly benefit the optimization of the metasurface's function.
Here we demonstrate an approach to lensless imaging of extreme
ultraviolet high harmonics that resolves the amplitude and phase of
nonlinear polarization at the active nanostructured surface of an MgO
crystal. Imaging the near-field distribution of high harmonics is the
gateway to optimized functional high-harmonic metasurfaces and the
integration of high harmonics on a chip.
Funder
Joint Center for Extreme
Photonics
Defense Threat Reduction
Agency
Air Force Office of Scientific
Research
Natural Sciences and Engineering Research
Council of Canada
W. M. Keck Foundation
Subject
Atomic and Molecular Physics, and Optics,Electronic, Optical and Magnetic Materials