Date of Degree

9-2022

Document Type

Dissertation

Degree Name

Ph.D.

Program

Physics

Advisor

German Kolmakov

Committee Members

Gabriele Grosso

Roman Kezerashvili

Oleg Berman

Yuri Lvov

Subject Categories

Condensed Matter Physics

Keywords

Dipolaritons, Exciton-polaritons, Optical transistor, Transition metal dichalcogenide, Optical computation

Abstract

The need for advances in optical computation leads us toward the investigation of novel methods of re-routing light in optical circuits. The behavior and properties of electrically driven exciton-dipolaritons in van der Waals transition metal dichalcogenides are investigated as a platform for realizing working elements of a polaritronic transistor. In this work, we consider exciton-dipolaritons, which are three-way superposition of cavity photons, direct excitons, and indirect excitons in a bilayer semiconducting system embedded in an optical microcavity. We start by providing motivation for our study of polaritons and then survey the fundamental properties of exciton-dipolaritons. We also survey the basic properties of emerging materials known as van der Waals transition metal dichalcogenide heterostructures and review the properties that make them promising materials to use for polaritronic switching devices.

Next, using the Langevin equation for dipolaritons, we study the room-temperature dynamics of dipolaritons in a transition-metal dichalcogenide (TMDC) heterogeneous bilayer. Specifically, we consider a MoSe2-WS2 heterostructure, where Y-shaped and Ψ-shaped channels guide dipolariton propagation. By quantifying the propagation of dipolaritons in both Y-shaped and Ψ-shaped channels guides, we demonstrate that polaritronic signals can be redistributed in the channels by applying driving voltages in optimal directions. We conclude by surveying applications of polaritons from scientific literature. Our findings open the route towards the design of efficient room-temperature dipolariton-based optical transistors and provide motivation for further inquiry into the study of dipolaritons and polaritronic devices.

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