Voltage-controlled 2π liquid-crystal terahertz phase shifter with indium-tin-oxide (ITO) nanowhiskers as transparent electrodes

Phase shift exceeding 2π at 1.0 THz with high transmittance was achieved in liquid-crystal THz phase shifters of three different designs. Indium-tin-oxide (ITO) nanowhiskers (NWhs) were employed as transparent electrodes. The driving voltage required for a 2π wave plate is as low as 5 Vrms.