Coupled Mode Theory for Semiconductor Nanowires

TL;DR

This paper develops a coupled mode theory model for semiconductor nanowires that incorporates light-matter interactions and boundary conditions, enabling simulation of nanowire lasing and comparison with experiments.

Contribution

It introduces a novel coupled mode formalism combined with semiconductor Bloch equations for modeling nanowire lasing, including boundary effects and material dynamics.

Findings

Successfully simulates emission characteristics of CdS and ZnO nanowire lasers.

Shows good agreement with FDTD simulations and experimental data.

Analyzes how cavity design and relaxation times affect lasing behavior.

Abstract

We present a model to describe the spatiotemporal evolution of guided modes in semiconductor nanowires based on a coupled mode formalism. Light-matter interaction is modelled based on semiconductor Bloch equations, including many-particle effects in the screened Hartree-Fock approximation. Appropriate boundary conditions are used to incorporate reflections at waveguide endfacets, thus allowing for the simulation of nanowire lasing. We compute the emission characteristics and temporal dynamics of CdS and ZnO nanowire lasers and compare our results both to Finite-Difference Time-Domain simulations and to experimental data. Finally, we explore the dependence of the lasing emission on the nanowire cavity and on the materials relaxation time.