Carrier-induced modulation of radiation by a gated graphene

TL;DR

This paper theoretically investigates how gating graphene can modulate near-IR and mid-IR radiation by altering interband transitions, achieving over 10% modulation depth depending on wavelength, gate voltage, and substrate properties.

Contribution

It provides a theoretical analysis of carrier-induced optical modulation in graphene on various substrates, highlighting potential for high-efficiency electrooptical modulators.

Findings

Modulation depth exceeds 10% depending on parameters.

Effective modulation in near-IR and mid-IR ranges.

Substrate choice influences modulation performance.

Abstract

The modulation of the transmitted (reflected) radiation due to change of interband transitions under variation of carriers concentration by the gate voltage is studied theoretically. The calculations were performed for strongly doped graphene on high-K (Al_2O_3, HfO_2, AlN, and ZrO_2) or SiO_2 substrates under normal propagation of radiation. We have obtained the modulation depth above 10% depending on wavelength, gate voltage (i.e. carriers concentration), and parameters of substrate. The graphene - dielectric substrate - doped Si (as gate) structures can be used as an effective electrooptical modulator of near-IR and mid-IR radiation for the cases of high-K and SiO_2 substrates, respectively.