Characterization of the second- and third-harmonic optical susceptibilities of atomically thin tungsten diselenide.

ABSTRACT: We report the first detailed characterization of the sheet third-harmonic optical susceptibility, ?⁽³⁾_s, of tungsten diselenide (WSe₂). With a home-built multiphoton microscope setup developed to study harmonics generation, we map the second and third-harmonic intensities as a function of position in the sample, pump power and polarization angle, for single- and few-layers flakes of WSe₂. We register a value of |?⁽³⁾_s|?? 0.9?×?10^-28?m³ V^-2 at a fundamental excitation frequency of ???=?0.8?eV, which is comparable in magnitude to the third-harmonic susceptibility of other group-VI transition metal dichalcogenides. The simultaneously recorded sheet second-harmonic susceptibility is found to be |?⁽²⁾_s| ? 0.7 × 10^-19?m²?V^-1 in very good agreement on the order of magnitude with recent reports for WSe₂, which asserts the robustness of our values for |?⁽³⁾_s|.

SUBMITTER: Rosa HG 

PROVIDER: S-EPMC6030073 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature