[21a-211A-1~11] 3.6 Ultrashort-pulse and high-intensity lasers

△ [21a-211A-7] High harmonic generation in reflection from GaAs and the propagation effects

〇Peiyu Xia¹, Changsu Kim¹, Faming Lu¹, Nobuhisa Ishii¹, Teruto Kanai¹, Hidefumi Akiyama¹, Jiro Itatani¹ (1.ISSP, the Univ. of Tokyo)

Keywords:solid high harmonic generation, nonlinear propagation effects, semiconductor

We demonstrate high harmonic generation (HHG) in GaAs in both transmission and reflection geometry, achieving up to the 15th harmonic (5.3 eV) in reflection well beyond the bandgap (1.4 eV) of GaAs. We find that the HHG process is significantly influenced by nonlinear effects during the propagation through GaAs with a thickness of tens of micrometers. HHG in reflection geometry is extremely free from propagation effects, opening a general approach in high harmonic spectroscopy.