Figure 4
From: Broadband tunable liquid crystal terahertz waveplates driven with porous graphene electrodes
Device characteristics. (a) Schematic set-up for transmittance polarization analysis. The apparatus consists of three metal wire grid polarizers (P), where P1 and P3 are fixed in a parallel orientation (defined as 0°), thereby allowing only TM-mode waves to be transmitted to the cell, whereas P2 can rotate between the 45° and –45° states. (b) Voltage-dependent temporal spectra of ordinary and extraordinary THz waves transmitted through the cell. (c) Frequency-dependent phase retardation calculated from the curves presented in b for different operating voltages. (d) Polarization evolution at 2.1 THz: linearly polarized at 0 V, elliptically polarized at 6 V, circularly polarized at 8.8 V, elliptically polarized at 20 V and linearly polarized at 50 V (orthogonal to the polarization at 0 V). THz, terahertz; TM, transverse magnetic.
