Influence of Anisotropic Liquid Crystal Polymer Films on Electromagnetic Resonance of Metasurface-Imbedded Liquid Crystal Cells

Liquid crystal polymer (LCP) films have been widely used as an alignment layer in liquid crystal (LC) cells due to their anisotropic properties. This work uses anisotropic LCP films to increase electromagnetic resonance shifts in metasurface-imbedded LC cells. The influence of the anisotropic LCP films on the electromagnetic resonance is investigated by fabricating metasurface-imbedded LC cells without and with LCP films. The LC cells without LCP films, with single LCP films, and with double LCP films have single LC layers, double LC layers, and triple LC layers, respectively. The double LC layers with thicknesses <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$D_\text{d}$</tex-math></inline-formula> have larger resonance frequency shifts than the single LC layers with thicknesses <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$D_\text{s}$</tex-math></inline-formula> as their thicknesses of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$D_{\mathrm{d}} = 2D_{\mathrm{s}}$</tex-math></inline-formula>. The result reveals that the LC molecules in the double LC layers have more homogeneous orientations than in the single LC layer due to the alignment and birefringence of the anisotropic LCP film. A large resonance frequency shift of 48 GHz is achieved in the triple LC layers with thicknesses <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$D_{\mathrm{t}} = 3D_{\mathrm{s}}$</tex-math></inline-formula>, indicating the double LCP films have a more significant effect on the resonance frequency shift of the triple LC layers. LCP films utilized in metasurface-imbedded LC cells have potential applications in terahertz communication, terahertz sensing, and terahertz imaging.