Magnetic field effect on terahertz emission from InAs surface excited by femtosecond laser pulses

Terahertz generation by means of optical lasers

“…When illuminated by femtosecond visible laser pulses, most semiconductor surfaces emit stronger or weaker electromagnetic transient with characteristic frequency in the THz range [54]. After photoexcitation of the carriers to the conduction band, surfaces of bulk semiconductors generate THz radiation due to ultrafast charge transport and resonant optical rectification [55][56][57][58][59][60][61][62][63][64][65][66]. The charge transport can be driven by the intrinsic surface electric field of the semiconductor [57,58] or by a difference in the mobilities of the electrons and holes (photo-Dember effect [59,60]).…”

“…The drift current due to the surface field is dominant for GaAs and InP, photo-Dember effect is dominant for narrow-gap semiconductors such as InAs and InSb. Terahertz pulse generation from InAs surface can be enhanced several times by a magnetic field [61,62] (Table 1, line 5). Additional continuous-wave laser illumination was found to be effective for THz radiation from the surfaces of semi-insulating GaAs and InP [63].…”