Abstract

Physical and optical characteristics of GaAs crystal in terahertz radiation are detected by asynchronous electro-optic sampling spectroscopy. In this experiment, we have obtained the refractive index and absorption rate of GaAs crystal in 0.1THz to 2.5THz radiation. The experimental results show that the average refractive index of GaAs crystal is 3.6. The mutation of refractive index and negative absorption rate occur in 1.12 THz, 1.66 THz and 2.20 THz. By analyzing the kinematics characteristics of transverse optical phonon of GaAs crystal in terahertz spectrum, we find that the coupling between terahertz wave and transverse optical phonon is the reason for the sudden change of refractive index and negative absorption phenomenon.

© 2014 Optical Society of America