Three Dimensional Broadband Tunable Terahertz Metamaterials

TL;DR

This paper demonstrates optically tunable 3D terahertz metamaterials with a 30% resonance frequency shift, enabling magnetic response control for advanced applications like switching, modulation, and polarization management.

Contribution

It introduces a novel fabrication of 3D array structures with tunable magnetic responses at terahertz frequencies using multilayer electroplating and photoexcitation.

Findings

Achieved a ~30% tuning of resonance frequency from 1.74 THz to 1.16 THz.

Transition observed from magnetic to bianisotropic response.

Demonstrated potential for dynamic control in terahertz applications.

Abstract

We present optically tunable magnetic 3D metamaterials at terahertz (THz) frequencies which exhibit a tuning range of ~30% of the resonance frequency. This is accomplished by fabricating 3D array structures consisting of double-split-ring resonators (DSRRs) on silicon-on-sapphire, fabricated using multilayer electroplating. Photoexcitation of free carriers in the silicon within the capacitive region of the DSRR results in a red-shift of the resonant frequency from 1.74 THz to 1.16 THz. The observed frequency shift leads to a transition from a magnetic-to-bianisotropic response as verified through electromagnetic simulations and parameter retrieval. Our approach extends dynamic metamaterial tuning to magnetic control, and may find applications in switching and modulation, polarization control, or tunable perfect absorbers.