Ultracompact Electro-Absorption Modulators Based on Novel Materials (I): Epsilon-Near-Zero Material and Electro-Absorption Modulation Based on Indium-Tin-Oxide.

摘要

Indium-tin-oxide (ITO) is widely used as transparent electrode in solar cells and displays. Recent work showed that ITO and other transparent conducting oxides can work as novel metamterials supporting highly confined surface plasmons. In this project, based on ITO we demonstrated a novel optical material with refractive index significantly smaller than unit, namely epsilon- near-zero (ENZ), which may find numerous applications. We also investigated the applications of ITO for electro-optic modulation. When applying gate voltage through electrolyte gel on an ITO-based structure, electric double layers are formed at the interfaces of ITO and electrolyte gel, which can significantly alter the optical properties of ITO. Two different structures are investigated, and modulation depth up to 38.8% has been achieved in the attenuated total reflection configuration. Preliminary result is presented for the real time response of an ITO/electrolyte gel/doped Si modulator.