We report direct measurement of hot-electron temperatures and relaxation dynamics for peak electron temperatures between 3400 and 11000 K utilizing two-pulse-correlation femtosecond (fs) thermionic emission. The fast relaxation times ( &1.5 ps) are described by extending RT characterizations of the thermal conductivity, electron-phonon coupling, and electronic specific heat to these high electron ternperatures.Hot-electron relaxation dynamics In the femtosecond laser intensity regime utilized here, the e1ectmn emission is dominated by the thermionic process which is strongly space charge suppressed.
We demonstrate fourth-harmonic generation from a GaAs(001) surface by using femtosecond pulses well below damage threshold. Our data reveal a strong fourfold anisotropic surface-specific polarization that is not present in second-harmonic generation and is nearly as strong as the bulk polarization.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.