High-efficiency optical terahertz modulation of aligned Ag nanowires on a Si substrate

Abstract

High-efficiency optical modulation of a terahertz pulse transmitted through aligned silver nanowires on a silicon substrate is demonstrated. Without optical excitation, the terahertz pulses mostly pass through the silver nanowires. However, an optically excited sample significantly modulates the transmittance compared with an excited silicon substrate. The enhanced modulation efficiency is explained by the redistribution effect of photo-carriers due to the nanowires. The simple structure of metal nanowires on a semiconductor substrate could be useful in implementing optically tunable terahertz wave modulators. Published by AIP Publishing.