Comparison of GaAs and DAST electro-optic crystals for THz time domain spectroscopy using 1.55 靘 fiber laser pulses

摘要

We report terahertz time-domain spectroscopy (THz-TDS) system based on Enfiber laser at 1.55 im wavelength that integrates an ion-irradiated Ino.53Gao.47As photoconductive antenna as an emitter and a DAST electro-optic sensor as a detector. DAST crystal cannot be used in traditional electro-optic sampling set-ups because of its high intrinsic birefringence. We propose here THz detection in DAST crystal by using an optical phase detection technique. The detected bandwidth is 5 THz. The performances of our THz-TDS systems based on electro-optic detection in a DAST crystal using optical phase detection is compared theoretically to the performance of a THz-TDS systems based on electro-optic detection in a GaAs crystal using traditional polarization rotation detection.