Redshift in the Optical Absorption of ZnO Single Crystals in the Presence of an Intense Midinfrared Laser Field

Shambhu Ghimire, Anthony D. DiChiara, Emily Sistrunk, Urszula B. Szafruga, Pierre Agostini, Louis F. DiMauro, and David A. Reis

Phys. Rev. Lett. 107, 167407 – Published 14 October 2011

Abstract

We report time-resolved electroabsorption of a weak probe in a $500 μ m$ thick zinc-oxide crystal in the presence of a strong midinfrared pump in the tunneling limit. We observe a substantial redshift in the absorption edge that scales with the cube root of intensity up to $1 TW / {cm}^{2}$ ( $0.38 eV {cm}^{2 / 3} {TW}^{- 1 / 3}$ ) after which it increases more slowly to 0.4 eV at a maximum applied intensity of $5 TW / {cm}^{2}$ . The maximum shift corresponds to more than 10% of the band gap. The change in scaling occurs in a regime of nonperturbative high-order harmonic generation where electrons undergo periodic Bragg scattering from the Brillouin zone boundaries. It also coincides with the limit where the electric field becomes comparable to the ratio of the band gap to the lattice spacing.

Received 30 April 2011

DOI:https://doi.org/10.1103/PhysRevLett.107.167407

Authors & Affiliations

Shambhu Ghimire^1,*, Anthony D. DiChiara², Emily Sistrunk², Urszula B. Szafruga², Pierre Agostini², Louis F. DiMauro², and David A. Reis^1,3,†

¹PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California, 94025, USA
²Physics Department, Ohio State University, Columbus, Ohio, 43210, USA
³Departments of Photon Science and Applied Physics, Stanford University, Stanford, California, 94305, USA