Terahertz Metamaterial Modulator Based on Phase Change Material VO2

Abstract

In this paper, a new type of terahertz (THz) metamaterial (MM) modulator has been presented with bifunctional properties based on vanadium dioxide (VO2). The design consists of a VO2 resonator, polyimide substrate, frequency selective surface (FSS) layer, and VO2 film. Based on the metal-insulator transition (MIT) of VO2, this structure integrated with VO2 material can achieve the dynamic modulation on both transmission and reflection waves at 2.5 THz by varying the electrical conductivity value of VO2. Meanwhile, it also exhibits adjustable absorption performance across the whole band from 0.5–7 THz. At the lower conductivity (σ = 25 S/m), this structure can act as a bandpass FSS, and, at the high conductivity (σ = 2 × 105 S/m), it behaves like a wideband absorber covering 2.52–6.06 THz with absorption A > 0.9, which realizes asymmetric transmission. The surface electric field distributions are illustrated to provide some insight into the physical mechanism of dynamic modulation. From the simulated results, it can be observed that this design has the capability of controlling tunable manipulation on both transmission/reflection responses at a wide frequency band. This proposed design may pave a novel pathway towards thermal imaging, terahertz detection, active modulators, etc.

Realization of multifunctional transformation based on the vanadium dioxide-assisted metamaterial structure

“…This transition property of VO 2 from an insulating state to a metallic state provides a feasible solution for achieving controllable multifunctional switching structures in metamaterials. [15][16][17][18][19][20] Y. N. Pei et al designed a composite metasurface consisting of VO 2 and dielectric materials. 21 By controlling the conductivity of VO 2 , they achieved flexible switching between absorption and polarization conversion functionalities.…”

A Thermally Controlled Multifunctional Metamaterial Absorber with Switchable Wideband Absorption and Transmission at THz Band

“…When the temperature is about 340 K, the conductivity of VO 2 will have a significant mutation of five orders and can realize the transition between insulator and metal. Based on this characteristic, VO 2 thin films have been widely used to design wideband absorbers, absorption–polarization converters, and wideband–narrowband conversion absorbers [ 25 , 26 , 27 ]. Recently, some researchers use VO 2 thin film to realize photonic crystal metamaterial−based sensors [ 28 , 29 , 30 ].…”

Tunable Terahertz Wavefront Modulation Based on Phase Change Materials Embedded in Metasurface

“…GeSbTe (GST) alloys as typical phase change materials have been used for many years in optical disk storage [ 17 , 18 ] and have been introduced to reconfigurable photonic devices recently. Compared to phase change material VO 2 [ 19 ], GST [ 20 ] has greater advantages in stability, conversion rate [ 21 ], and non-volatility [ 22 ]. GST can be converted between two states (usually amorphous and crystalline state) or the intermediate states by external excitation (such as thermal [ 23 ], electrical [ 24 ], and optical excitation [ 25 ]).…”