Sunday, August 30, 2015
Abstract-Angular dependence of terahertz emission from semiconductor surfaces photoexcited by femtosecond optical pulses
Ryotaro Inoue, Kazuhisa Takayama, and Masayoshi Tonouchi
In this paper, the angular dependence of terahertz (THz) emission from semiconductor surfaces photoexcited by femtosecond optical pulses is reported. Time-domain waveforms of THz emission from (100) surfaces of semi-insulating gallium arsenide andp-type indium arsenide are measured at various angles after careful suppression of the nonlinear optical rectification effect. THz emission angle-frequency patterns under focusing conditions of the excitation beam are regarded as radiation from an electric dipole moment located on the semiconductor surface. Based on the experimental results in the magnetic field parallel to the semiconductor surface, we discuss the ultrafast carrier dynamics on the surfaces of both semiconductors.