Berlin 2015 – wissenschaftliches Programm
HL 57.3: Vortrag
Mittwoch, 18. März 2015, 16:45–17:00, EW 015
Giant Magnetic-Field-Induced Third-Harmonic Generation in Semiconductor GaAs — David Brunne1, •Walter Warkentin1, Victor Pavlov2, Roman Pisarev2, Anna Rodina2, and Dmitri Yakovlev2 — 1Experimentelle Physik 2, Technische Universität Dortmund, Dortmund, Germany — 2Ioffe Physical-Technical Institute, Russian Academy of Sciences, St. Petersburg, Russia
GaAs has the noncentrosymmetric crystallographic structure of zinc blend type (P.G. 43m) in which nonlinear optical process of third-harmonic generation (THG) is allowed in the electric dipole approximation. However, an external magnetic field on the order of 10 T gives rise to an enormous enhancement of the THG intensity by a factor of hundred. We observed a resonance in the THG spectra of GaAs in the vicinity of the 1s-excitonic state, which is related to the four-photon THG processes. The observed resonance is attributed to the intricate modification of polariton-excitonic structure in magnetic field mixing dark and bright 1s-excitonic states. Magnetic-field, rotational anisotropy and temperature studies allowed us to unambiguously confirm the magnetic-field-induced THG mechanism in GaAs. It is important that suggested mechanism of the THG enhancement can be valid for other semiconductors as well.