Tunable Terahertz Metamaterial with Electromagnetically Induced Transparency Characteristic for Sensing Application

Abstract

We present and demonstrate a MEMS-based tunable terahertz metamaterial (TTM) composed of inner triadius and outer electric split-ring resonator (eSRR) structures. With the aim to explore the electromagnetic responses of TTM device, different geometrical parameters are compared and discussed to optimize the suitable TTM design, including the length, radius, and height of TTM device. The height of triadius structure could be changed by using MEMS technique to perform active tunability. TTM shows the polarization-dependent and electromagnetic induced transparency (EIT) characteristics owing to the eSRR configuration. The electromagnetic responses of TTM exhibit tunable characteristics in resonance, polarization-dependent, and electromagnetically induced transparency (EIT). By properly tailoring the length and height of the inner triadius structure and the radius of the outer eSRR structure, the corresponding resonance tuning range reaches 0.32 THz. In addition to the above optical characteristics of TTM, we further investigate its potential application in a refraction index sensor. TTM is exposed on the surrounding ambient with different refraction indexes. The corresponding key sensing performances, such as figure of merit (FOM), sensitivity (S), and quality factor (Q-factor) values, are calculated and discussed, respectively. The calculated sensitivity of TTM is 0.379 THz/RIU, while the average values of Q-factor and FOM are 66.01 and 63.83, respectively. These characteristics indicate that the presented MEMS-based TTM device could be widely used in tunable filters, perfect absorbers, high-efficient environmental sensors, and optical switches applications for THz-wave optoelectronics.

High-Performance Quality Factor Based Sensor With Diagonal Cylinder Metasurface of the Bound State in the Continuum

“…As high-Q resonance has wide prospects in many fields, including narrowband filtering [1], microwave and optical filters, thin-film sensing [2], and guided-Mode resonant gratings [3]. The high-Q resonance based on high-index dielectric nanoparticles [4], electromagnetic induction transparency (EIT) [5], and surface plasmon polaritons (SPPs) [6] has been reported in previous studies. Recently, a class of asymmetric metasurfaces with high-Q resonance based on the bound states in the continuum (BIC) phenomenon has attracted wide attention.…”

Tunable MEMS-based metamaterial nanograting coupler for C-band optical communication application

“…Metamaterial has extraordinary electromagnetic characteristics that originates from the specific geometric structure arranged artificially and its subwavelength configuration [1]. By changing the geometrical parameters and material structures of metamaterial, a strong electromagnetic response covering the range from visible light [2][3][4][5], infrared (IR) wave [6][7][8][9] to terahertz (THz) frequency [10][11][12][13] can be realized. It has been proved that metamaterial can achieve unique optical characteristics, such as negative refractive index [14], strong transmission [15], perfect absorption [16][17][18][19], and holographic imaging [20], due to its exotic permittivity and permeability.…”

Reconfigurable Split Ring Resonators by MEMS-Driven Geometrical Tuning

“…Reconfigurable devices, circuits and metamaterials are a major trend in current research in physics and engineering [ 1 ] with applications ranging from ICT [ 2 ] to sensors and monitoring technologies [ 3 ]. In this respect, metamaterial-inspired architectures [ 4 ] and split ring resonators (SRRs) attracted large interest [ 5 , 6 , 7 ]. On one side, their response can change as a function of an external condition, and this is relevant for the implementation of sensors exhibiting high performances and ultimate sensitivity [ 8 , 9 , 10 ].…”