SKM 2023 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 37: Poster: Ultrafast Electron Dynamics at Surface and Interfaces II

O 37.3: Poster

Dienstag, 28. März 2023, 18:00–20:00, P2/EG

Second harmonic spectroscopy of Cu(001) surfaces — •Newsha Vesalimahmoud, Jinghao Chen, Mahendra Kabbinahithlu, Ping Zhou, Uwe Bovensiepen, and Andrea Eschenlohr — University of Duisburg-Essen, Faculty of Physics and CENIDE, Lotharstr. 1, 47057 Duisburg, Germany

The nonlinear optical technique of second harmonic generation (SHG) is a surface- and interface-sensitive tool in centrosymmetric materials, which is used to study electron dynamics at metal surfaces. We characterize the polarization and wavelength dependent SHG on a Cu(001) surface using a fundamental beam in the wavelength range of 500 - 700 nm. Polarization dependent measurements show the p-P SHG yield is almost a factor of 1.5 larger than s-P SHG, because more non-zero susceptibility tensor elements are involved in the former and the intrinsic absolute value of χ_zzz⁽²⁾ is much larger than the only relevant component χ_zxx⁽²⁾ in the latter. We also measure the spectral dependence of the SHG intensity, which shows an increase up to a maximum at 2.33 eV. Since the 3d band peak of copper lies about 2.3 eV below Fermi level, a fundamental beam at this photon energy can resonantly excite 3d electrons to the Fermi level, which largely increases the overall probability of SHG processes. Moreover, we discuss electron dynamics analyzed through pump-probe SHG at on and off-resonant photon energies.