Negative terahertz conductivity in remotely doped graphene bilayer heterostructures

TL;DR

This paper demonstrates that remote doping in graphene bilayer heterostructures enhances negative terahertz conductivity, enabling more efficient THz lasers at room temperature by surpassing intraband absorption.

Contribution

It introduces remote doping as a method to increase interband photon generation and negative THz conductivity in graphene bilayers, improving THz laser performance.

Findings

Remote doping enhances interband photon generation.

Negative THz conductivity achieved at room temperature.

Potential for higher THz gain in doped GBL heterostructures.

Abstract

Injection or optical generation of electrons and holes in graphene bilayers (GBLs) can result in the interband population inversion enabling the terahertz (THz) radiation lasing. The intraband radiative processes compete with the interband transitions. We demonstrate that remote doping enhances the indirect interband generation of photons in the proposed GBL heterostructures. Therefore such remote doping helps surpassing the intraband (Drude) absorption and results in large absolute values of the negative dynamic THz conductivity in a wide range of frequencies at elevated (including room) temperatures. The remotely doped GBL heterostructure THz lasers are expected to achieve higher THz gain compared to previously proposed GBL-based THz lasers.