Research on dielectric properties of gallium arsenides by using THz-TDS

By using terahertz time domain spectroscopy (THz-TDS) system, the terahertz dielectric properties of various gallium arsenides were tested in the frequency range extending from 0.2 to 1.5 THz. The power absorption coefficient and refractive index of various resistivity gallium arsenides were measured and compared. The refractive index of the high resistivity and ultra-high resistivity GaAs are equal to be 6.53 and 5.9, respectively. The variation of the refractive index of the GaAs was less than 1%, ranging from 0.2 to 1.5THz, but the absorption coefficient of the ultra-high resistivity GaAs showed very different frequency-dependent behaviors, ranging from 0.02cm−1 to 2.21cm−1, within the investigated frequency range. The results show that the ultra-high resistivity GaAs will be a good candidate material for terahertz transmission waveguide.