All-dielectric terahertz metamaterial with polarization switching characteristic

Abstract

All silicon dielectric metamaterial (SDM) composed of two outer symmetric semi-circular rings and two inner symmetric split-ring resonators (SRRs) is presented. The electromagnetic responses of SDM device with different structure heights in transverse electrical (TE) and transverse magnetic (TM) modes are studied by numerical simulations and experiments. By increasing structure height of SDM device, the resonances of the SDM devices exhibit red-shift and the resonant intensities become stronger. The shifting ranges of resonances are 0.36 THz in TE mode and 0.27 THz in TM mode. Furthermore, the SDM device with structure height of 100 μm demonstrates great resonant intensity, and two extra resonances are generated at 1.60 THz and 2.26 THz in TM mode. By further investigating the polarization characteristics of SDM device with structure height of 100 μm, there are two linear trends for the polarization switching function at 1.60 THz and 2.10 THz. The corresponding correction coefficients are 0.99608 and 0.99726 and the modulation depths are 74 % and 74.5 % for the resonance at 1.60 THz and 2.10 THz, respectively. This SDM design paves the way to the strategy of the development of frequency filtering, polarization switching, and resonance modulation characteristics in the THz-wave applications.