Ultrafast Switching in Terahertz Metamaterials using Ion Implanted Silicon on Sapphire

TL;DR

This paper demonstrates ultrafast terahertz metamaterial resonance switching achieved by optically exciting ion-implanted silicon, enabling control within a few picoseconds, which is promising for ultrafast terahertz devices.

Contribution

It introduces a novel method for ultrafast resonance switching in terahertz metamaterials using ion-implanted silicon, with experimental and simulation validation.

Findings

Resonance switches OFF in 4 ps and ON in 20 ps.

Electric field at the resonator gap disappears upon optical excitation.

Ultrafast free carrier recombination enables rapid switching.

Abstract

We demonstrate ultrafast resonance switching of terahertz metamaterials through optical excitation of radiation damaged silicon placed in the gap of single split gap ring resonator. We observe the dynamic switching OFF of the fundamental resonance mode on a time scale of 4 picoseconds (ps) followed by the switching ON of the same resonance after 20 ps. Electric field distributions in the metamaterials unit cell derived through numerical simulations clearly support our experimental observations, showing that the high electric field at the resonator gaps, responsible for inductive-capacitive resonance (LC), completely disappears and switches OFF the resonance after being optically excited. The ultrafast switching of the metamaterial resonance is attributed to the generation of free carriers in ion-implanted silicon and their recombination at an ultra-short time scale. Such silicon based active control of metamaterials can lead to the ultrafast terahertz metadevices.