Liquid Crystal-Based Terahertz Metamaterials

Liquid crystal–based terahertz metamaterials exploit the electrically reconfigurable anisotropy of liquid crystals (LCs) to achieve active control over electromagnetic waves in the 0.1–10 THz band. By embedding a thin LC layer within or atop subwavelength resonant structures, the effective permittivity and magnetic response of the composite can be tuned under modest voltages. This permits dynamic modulation of amplitude, phase and polarisation as well as frequency‐selective absorption, beam steering and lensing functionalities. Advances in transparent electrode technologies, patterning methods and LC formulations with high birefringence and low loss have enabled compact, low‐power devices operating at room temperature. Such reconfigurable components promise to underpin next‐generation terahertz systems for high‐speed wireless links, adaptive imaging, spectroscopy and sensing, offering both rapid switching and wide tuning ranges in a lightweight, planar format.

Research from Nature Portfolio

Investigations of fishnet‐style metamaterial cavities incorporating nematic LCs have demonstrated voltage‐driven tuning of magnetic resonances by over 150 GHz. A submicrometre LC layer sandwiched between perforated metallic meshes forms a cavity whose resonance frequency shifts in response to molecular reorientation under low bias. The resulting metamaterial exhibits fast switching speeds—several orders of magnitude quicker than bulk LC devices—while preserving high quality factors in the terahertz range. Such structures validate the concept of electrically reconfigurable metamaterial elements for dynamic control of wave propagation, paving the way for switchable filters, modulators and phase‐shifting components in terahertz platforms.

Liquid Crystal-Based Terahertz Metamaterials publication trend

The graph below shows the total number of articles in liquid crystal-based terahertz metamaterials across all publications each year (not limited to Nature Index journals).

Technical terms

Liquid crystal: A soft matter phase exhibiting long‐range orientational order of rod‐like molecules, whose dielectric tensor can be reoriented by electric fields.

Metamaterial: An engineered composite with subwavelength structural units designed to yield electromagnetic properties not found in natural materials.

Terahertz: The portion of the electromagnetic spectrum spanning frequencies roughly between 0.1 and 10 THz, bridging microwaves and infrared.

Birefringence: The property of an anisotropic medium to exhibit two distinct refractive indices depending on the polarisation and propagation direction of light.

Metasurface: A two‐dimensional array of resonant or gradient‐phase elements that imparts spatially varying amplitude, phase or polarisation changes to an incident wavefront.

Geometric phase: A phase shift introduced by spatial variation in the orientation of anisotropic elements, independent of frequency and arising from polarization evolution.

References

1. Tunable terahertz fishnet metamaterials based on thin nematic liquid crystal layers for fast switching. Scientific Reports (2015).
2. Broadband large-angle beam scanning with dynamic spin energy distribution based on liquid crystal cascaded bilayer metasurface. Nanophotonics (2023).
3. Liquid crystal integrated metalens with tunable chromatic aberration. Advanced Photonics (2020).