Influence of temperature on resonant properties in terahertz subwavelength metal structures

By using terahertz time domain spectroscopy(THz-TDS), the transmission and resonance properties of terahertz subwavelength metal structures at different temperatures were studied. The transmission of U- and E-shaped structures decreased gradually with temperature increasing from 80 K to 380 K. Meanwhile, the low resonance frequency showed a slight red-shift. Through the study of temperature-dependent transmission spectra at resonance and non-resonance regions, the phenomenon of transmission decreasing was attributed to the increasing of carrier concentration in GaAs substrate. The weakened resonant strength originated from the resonate quench by temperature-generated carriers in substrate. The red-shift was due to the increase of refractive index. The investigation could provide some meaningful guides in pratical application of terahertz functional devices.