Figure 1
From: Broadband tunable liquid crystal terahertz waveplates driven with porous graphene electrodes
Tunable THz waveplate. (a) The cell is composed of a front fused silica substrate covered with a subwavelength metal wire grid and a rear fused silica substrate covered with porous graphene. Both substrates are spin coated with SD1 alignment layers, and 250-μm-thick Mylar is used to separate the two substrates. NJU-LDn-4 LCs are capillary filled into the cell. Also shown are the frequency- and polarization-dependent transmittances of (b) the subwavelength metal wire grid (a photograph of the grid is presented in the inset) as well as (c) pristine, UVO-treated and then SD1 spin-coated CVD-grown few-layer graphene films. CVD, chemical vapor deposition; LC, liquid crystal; SD1, sulfonic azo dye; TE, transverse electric; THz, terahertz; TM, transverse magnetic; UVO, UV/ozone.
