Photoconductive Detection of Ultrabroadband Terahertz Radiation from Semiconductors

Abstract

Broadband detection of terahertz radiation with a photoconductive (PC) antenna fabricated on low-temperature-grown GaAs (LT-GaAs) is reported. The detection of up to 60 THz with an LT-GaAs PC antenna gated with 15 fs laser pulses is demonstrated. The spectral response of the PC antenna is compared with that of electro-optic sampling technique. The frequency response of the PC antenna is found to be determined by the temporal profile of the carrier number. The detectable bandwidth of the PC antenna is investigated in terms of the gating pulse width. The potential bandwidth of the PC antenna is found to be broader than reported before even with the gating pulse width of 45 fs.