Electrically tunable liquid crystal terahertz phase shifter driven by transparent polymer electrodes

The use of DMSO-doped-poly (3,4-ethylenedioxythiophene):poly (4-styrenesulfonate) (PEDOT:PSS) thin films produced by spin coating as transparent electrodes for a liquid crystal terahertz (THz) phase shifter is reported. The transmittance of these newly proposed transparent electrodes is as high as ∼90%. The phase shifter provides continuous tunability, full electrical controllability, and low-voltage operation at THz frequencies. A maximum phase shift of 129.4° at 1.17 THz is achieved in a 500 μm-thick cell when the driving voltage is as low as 6.7 V (rms).