55th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Monday–Friday, June 3–7, 2024;
Fort Worth, Texas
Session G10: High Harmonic Generation
10:30 AM–12:30 PM,
Wednesday, June 5, 2024
Room: 204AB
Chair: Mette Gaarde, Louisiana State University
Abstract: G10.00005 : Solid-state high harmonic generation spectroscopy of quantum materials in complex environments*
11:36 AM–12:06 PM
Abstract
Presenter:
Michael Zuerch
(University of California, Berkeley)
Author:
Michael Zuerch
(University of California, Berkeley)
Solid-state High Harmonic Generation (sHHG) spectroscopy offers significant potential for the characterization of nanomaterials and 2D quantum materials with sensitivity to lattice and electronic dynamics, including correlated phenomena and properties such as topology. sHHG spectroscopy is particularly promising for studying material properties and dynamics in challenging sample environments, including liquid-phase and high-pressure diamond cells, where traditional tools of condensed matter physics fail. In this presentation, I will discuss our recent work where we explore the sHHG polarization anisotropy in monolayer MoS2, specifically examining how it varies with the crystal's orientation relative to the polarization of the mid-infrared laser field. Our experiments, conducted across several laser wavelengths, revealed a notable angular shift in the parallel-polarized odd harmonics at energies above approximately 3.5 eV. We determined that this shift is linked to differences in the recombination dipole strengths that involve multiple conduction bands. This finding is not only specific to the material in question but also augments the angular dependence dictated by the dynamical symmetry properties of the crystal in interaction with the laser field. Expanding on these results, we incorporated a diamond anvil cell (DAC) into our setup to investigate pressure-induced phase transitions in MoS2. Our high-pressure experiments on MoS2, both in bulk and at the monolayer limit, revealed a structural phase transition at approximately 25 GPa, characterized by significant changes in symmetry and a closure of the bandgap, indicating a transition to a metallic phase. These results underscore the versatility and efficacy of sHHG spectroscopy in probing quantum materials in complex environments. Finally, I will briefly discuss recent advancements, including sHHG on resonant dielectric metasurfaces for efficient optical harmonic generation, ellipticity-dependent high-order harmonic generation in ZnO, size-dependent suppression of high-order harmonics in CdSe quantum dots, and the observation of momentum-dependent electron-phonon scattering as predominant mechanism for dephasing in sHHG.
*Funding by the National Science Foundation (NSF-DMR 2247363) is acknowledged.