Towards On-Chip Plasmonic Amplifiers of THz Radiation

Introduction

Thirty years ago, Dyakonov and Shur opened a new field in solid-state physics and electronics - plasma-wave electronics. They theoretically predicted that:

1. In nano-transistors, plasma waves may oscillate at THz frequencies far beyond the devices’ cut-off GHz frequencies.
2. THz radiation can be detected by plasma nonlinearities.
3. The current flow can lead to the generation of THz radiation.

Current Status of THz Plasmonics

The detection part of the “plasmonics promise” was proven, and nowadays THz plasmonic detector arrays are widely used. In the case of emitters, the task turned out to be considerably more complicated.

Only recently (PRX 10, 031004, 2020; with my team’s participation), room temperature, current-driven amplification of incoming THz radiation has been demonstrated in innovative double grating gate structures based on graphene, one of the most promising materials for plasmonics.

Implications of Breakthrough Results

These breakthrough results indicate that existing models of plasmonic systems should be reconsidered. Using new 2D materials or their heterojunctions with innovative geometries may lead “Towards on-chip plasmonics amplifiers of THz radiation,” which is TERAPLASM’s main objective.

Experimental Methodology

The experimental methodology will involve:

• Fabrication and THz spectroscopy studies of graphene.
• Alternative-to-graphene unique HgTe and GaN-based systems with a high mobility 2D electron gas.

This will allow for the identification of the physical mechanisms responsible for the observed THz plasmonic amplification and the selection of the optimum systems for THz devices.

Theoretical Research

In parallel, theoretical research will develop physical models of THz plasmonic amplification studied in the experimental part of the project.

Project Goals

By conducting extensive technological, spectroscopic, and theoretical research, TERAPLASM will aim to answer the old basic physics and electronics questions on the feasibility of on-chip plasmonics amplifiers of THz radiation. This has important potential applications in:

• Wireless telecommunication
• Biosensing
• Security
• Others