Comparison of terahertz time-domain spectroscopy based on photoconductive antenna and electro-optic sampling and the optical parameter measurement of GaSe nanofilm in THz band

Abstract

Due to the advantages of THz wave in nondestructive examination (NDE) of materials, terahertz time-domain spectrometer (THz-TDS) has become a mature device for THz detection. Thus, improving signal-to-noise ratio (SNR) and reliability of THz-TDS are considered as the vital work. In this paper, photoconductive antenna (PCA) and electro-optic sampling (EOS) were used to measure the intensity of THz wave. Under the same laser conditions, the residual pump laser and probe laser polarization in THz-TDS were studied for influence on the SNR of THz wave. The experimental results demonstrated the significance of the existing THz-TDS. In THz band, the refractive index of GaSe nanofilm varied from 3.3 to 4.1 with the frequency range from 0.3 THz to 0.6 THz.