Strong-Field Terahertz Control of Plasmon Induced Opacity in Photoexcited Metamaterial

TL;DR

This paper demonstrates ultrafast terahertz control over plasmon-induced opacity in a photoexcited metamaterial, revealing complex interactions between photocarriers and plasmon oscillations with potential for high-speed plasmonic applications.

Contribution

It introduces a method to manipulate plasmon resonances in metamaterials using intense terahertz pulses, showing dynamic control of plasmon-induced opacity.

Findings

Terahertz pulses transiently restore plasmon resonances

Photocarriers reduce mobility via intervalley scattering and tunneling

Ultrafast terahertz control enables potential ultrahigh-speed plasmonics

Abstract

A terahertz metamaterial consisting of radiative slot antennas and subradiant complementary split-ring resonators exhibits plasmon induced opacity in a narrow spectral range due to the destructive interference between the bright and dark modes of the coupled oscillators. Femtosecond optical excitations instantly quench the mode coupling and plasmon oscillations, injecting photocarriers into the metamaterial. The plasmon resonances in the coupled metamaterial are transiently restored by intense terahertz pulses. The strong terahertz fields induce intervalley scattering and interband tunneling of the photocarries, and achieve significant reduction of the photocarrier mobility. The ultrafast dynamics of the nonlinear THz interactions reveals intricate interplay between photocarriers and plasmon oscillations. The high-field THz control of the plasmon oscillations implies potential applications to ultrahigh-speed plasmonics.