Tunable terahertz fishnet metamaterial

Abstract

A tunable fishnet metamaterial (TFMM) was designed and fabricated to prove its potential in controlling terahertz radiation (0.1 THz~10THz). A model to retrieve refractive index of single layer fishnet metamaterial (SLFM) was developed and applied to study the tunable frequency range of TFMM. Reference planes that define the material boundaries of SLFM and multilayer fishnet metamaterial (MLFM) were investigated to show that the material property of fishnet metamaterial is a function of layers. The issue of applying current model to MLFM was discussed.The TFMM infiltrated with a voltage-controllable polymer dispersed liquid crystal (PDLC) was fabricated and tested by terahertz time domain spectroscopy (THz-TDS). An encapsulating technique that covers PDLC with a polyimide layer (skin layer) was applied to prevent volatile liquid crystal from escaping the PDLC and enable the deposition of metal layer. Concept of tuning TFMM infiltrated with PDLC (PDLC-TFMM) was proven by measuring the frequency shift in the reflection coefficient. The negative refractive index of PDLC-TFMM was achieved. The reliability issue of current PDLC-TFMM was discussed.II

Metacomposite characteristics and their influential factors of polymer composites containing orthogonal ferromagnetic microwire arrays

“…This is reminiscent of the recent studies either by restricting liquid crystal in the certain periodic structure, 21,22 or employing resistor network based on transformation optics theory to electrically tune the metamaterials. 23 However, disadvantages of complexity in manufacturing and the burden of extra DC power source in these studies cannot be ignored.…”

Electrically Tunable Critically Coupled Terahertz Metamaterial Absorber Based on Nematic Liquid Crystals

“…This way, notable modulation depths in transmittance [6,7,[9][10][11] or reflectance [5,8,12,13] have been reached even for deeply subwavelength cell thicknesses.…”

“…A promising approach towards more compact and faster LC-tunable terahertz components [5][6][7][8][9][10][11][12] has been to infiltrate the LC into a resonant metamaterial structure and utilize the ensuing large electric-field enhancement to strengthen the interaction between the incoming field and the LC. This way, notable modulation depths in transmittance [6,7,[9][10][11] or reflectance [5,8,12,13] have been reached even for deeply subwavelength cell thicknesses.…”

Liquid-crystal tunable fishnet terahertz metamaterials

“…They have been long used as the active element in electric field-actuated photonic devices [4], and recently their use has been extended into the field of THz science and metamaterials [5][6][7][8]. LC-tunable devices show extremely low power consumption, combined with large refractive index modulation and polarization control features.…”