Comparison Study of Gold Nanorod and Nanoparticle Monolayer Enhanced Optical Terahertz Modulators

This is the authors' abstract. We don't add key points for this paper.

Nanostructure modified semiconductors show enormous potential for the optical terahertz (THz) spatial modulation due to their enhanced modulation depth along with their inherent broad bandwidth, small insertion loss, and fast modulation speed. As a result, it is necessary to explore the mechanism of the performance enhancement by the interface modification. Here, the self-assembled monolayer of gold nanorods and nanoparticles was coated on silicon to enhance the optical modulation depth of THz wave. Comparison experiment and the finite-difference time-domain simulation have been performed between the self-assembled monolayer of gold nanorods and nanoparticles to understand the mechanism for improving the light modulation of THz wave. We found that the modulation depth and the speed of THz wave were mainly determined by the light resonance frequency of gold nanoparticles/nanorods and the area with enhanced light intensity on silicon surface. Our results provide a guide for the light-controlled THz modulator based on the nanostructure modified semiconductor.